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Chapter Text

It was afternoon on New Year’s eve. The air was still, and it was not snowing anymore, but the sky was blotted out by dark grey clouds.

Tanjirou sat at the end of the table, eating his food, talking happily with the other members of his family. Rokuta, Shigeru, Hanako, Takeo, Nezuko, and Kie sat next to him, their scents mixing into a cocktail of contentment.

It was always these moments that he savoured the most. A family united by the strongest of bonds, all loving and helping each other… And all happy, despite the poverty of the family sometimes not even allowing for everyone to eat their fill.

And all happy, even if Father wasn’t with them anymore… The hole left by his absence could not be filled, but it could be recognised. Tanjuurou would never be forgotten, as long as they lived. He would have wanted them to be happy, to live on unburdened, and so they would live. Tanjirou would dance his kagura in a few hours. That was proof enough of his mark.

And yet, masked by the scents of happiness, a horrible stench had started filling the air. A stench not only of blood, but also of flesh and decay.

And with it, came the scents of intense feelings.

Anticipation. Malice. Hatred. Fear.

Fear?

In any case, the owner of the scent was foreign, dangerous, and human. Or maybe just human enough to feel.

Tanjirou excused himself.

“Mom, someone’s coming. I’ll take the door, it might be dangerous.”

He walked over to where the axe was secured on the wall, the sword still left outside, and just as he wrapped his hands around the handle, a knock rang out.

Tanjirou, walked over, axe in hand.

“Who is it?”

“A weary traveller.”

“I’ll step outside. Please just wait a second.”

As Tanjirou opened the door, he was greeted with a man dressed in a Western suit. The man practically oozed the scent of malice. Rather than regular pupils, this man’s eyes appeared as vertical slits, like a cat’s. (Was this a demon?)

And even with the door open just a crack, the visitor seemed to have seen something. His pupils constricted so much they were no more than lines amid the glowing reds of his irises.

The scent of malice turned into real violence.

What looked like tentacles erupted from his back. Tanjirou dodged to the side, but the man blurred into the building and continued his assault, blending into the darkness that seemed to pour in from the shredded door.

The startled voices of his family told Tanjirou that he needed to do something, fast.

Though he was more used to a sword’s grip rather than an axe’s, he swung his weapon at the enemy.

Instead of connecting with the target, the axe flew out of his hands as he crashed through a wall into the next room, where his family was getting up from their knees. Kie tried to shelter her children against the mysterious man, whose eyes now shone and whose tentacles now extended through the large hole in the wall. Crashing against another wall was enough to stop Tanjirou’s momentum, and he slid down to the floor, the air knocked completely out of his lungs, spots dancing in his blurry vision and blood swimming up his throat.

He could only watch as the man took the lives of the people he held most dear. What happened in a second felt like it took minutes. Long, agonising minutes in which an atrocity took place.

Kie lost her head, her blood coating the wooden floor and the faces of her children.

Shigeru and Takeo got their torsos diced, and laid on the floor, bleeding out.

Hanako got cut straight down the middle, the tentacle laying bare her organs, which spilled out with nothing left to hold them in place.

Just as the tentacles reached for Nezuko and Rokuta, Tanjirou finally managed to breathe, and he shot up, grabbing a knife on the table and slashing the intruder’s neck with a blade that wasn’t red a second ago.

The demon’s head held on by a thread, as blood gushed momentarily from the wound before the two sides reattached completely. The spilled blood pooled in the food Tanjirou’s family had been eating. It stained the rice, collected in the empty pot at Kie’s end of the table, and splattered all over Tanjirou’s clothes. It only added to the growing pools on the floor.

The attacker’s rage, which had been climbing for the whole encounter, climaxed. He shot out two tentacles which wrapped around Tanjirou, shoving Tanjirou to the ground with one. A wet squelch came from behind the boy.

“Your sister will eat you, sun breather.”

The man’s tentacle snapped at the back of his neck, and his consciousness blanked out, the image of red slitted eyes and the scent of fear burning themselves into his mind.

…

Sun breathing.

-

He remembered the day he learned about sun breathing.

Tanjuurou laid on his death-bed. It was obvious to everyone, even if nobody wanted to accept it. His breath had always been even, but now it was broken, whistling like the wind against an abandoned house.

He had been the family’s foundation and support, but as his chronic sickness worsened, he started passing on his duties to Tanjirou.

His first son sat by the bed.

Tanjuurou was still speaking. The words were ripping themselves from his vocal cords, and it was doubtless anyone else would have passed out from the pain. Still, red eyes stayed open resolutely. “Tanjirou. I know you will grow to be an admirable man.”

He broke into a coughing fit, but there was still fire in his eyes.

When he recovered: “I keep a book… passed on from our ancestor Sumiyoshi inside a false wall in the kitchen. Please find it and read it. I leave that, my sword, and our kagura, to you.”

His whole family sat gathered around their pillar.

Tears coated every face.

“Please, live on…”

The light faded from his eyes.

-

Tanjirou’s eyes snapped open.

He saw Nezuko’s eyes as pink blurs above him.

“Don’t… Move, Ne… zuko. You’re… injured.”

He felt an iron taste in his mouth. As his vision returned, he noticed that Nezuko’s clothes looked blood-stained, but she did not look injured. The hole in her kimono led to undisturbed skin.

Her eyes were slitted, just like the ones of that man. And from them leaked a stream of tears. Blood stained her jaw and the fangs in her mouth.

In her hands, which now bore claws, she held the bloody iron pot. She was tipping the liquid inside into Tanjirou’s mouth. He didn’t have enough strength yet to protest.

As he regained his senses, he noticed the pain in his right shoulder. From the pressure on it, he could tell that it was wrapped in some sort of bandage. He could feel more bandages around his body, no doubt soaked with his blood. He would probably bleed out soon. No doctor was close enough to this mountain to treat his wounds in time.

Tanjirou regained control of his muscles just as Nezuko put the pot back down onto the floor. As he got up to his knees, almost losing consciousness from the blood rushing away from his head, Nezuko, who had been kneeling next to him, wrapped him in a tight hug. She rose to her feet, supporting Tanjirou by his armpits.

Tanjirou wobbled on his legs a bit, but eventually stabilised.

“I’m fine, Nezuko.”

The sun had almost set. The grey clouds were losing their last vestiges of brightness, gaining a slight orange tint.

Nezuko stared at Tanjirou in concern, as the latter registered each of the corpses in the room, the blood on every surface, and the pool of saliva where Nezuko had fallen. She moved her mouth as if to speak, but all that came out were some vowels and low growls. Was she mute?

Tanjirou’s eyes fell on the neatly folded robe used for the family’s Hinokami kagura. He remembered that it was still New Year’s eve, and that the sun hadn’t set.

“Nezuko. Do you think I should do the kagura this year?”

She seemed to ponder a bit. Slowly, her tears were drying.

She wiped them away with her bloody sleeve. Tanjirou’s sister gave him a once-over before nodding, humming lightly.

His sense of smell slowly returned to him, not only exposing the terrible scent of blood but also the concern and sadness Nezuko felt, as she looked at him.

Tanjirou gingerly donned the robe, and walked out through the shreds of wood that once were a front door. He would do the kagura. He was going to die anyway. Already, the clouds seemed dimmer, and his feet were swimming on the too-uneven ground. At least his sister should be happy.

Instead of the ceremonial staff, he picked up his father’s sword from behind the house.

And he danced.

Determination allowed him to push through the first few cycles, as he lost himself to the movements despite feeling like he was going to collapse, but as his breathing stabilised Tanjirou fell into the familiar rhythm he had practised every day since his father’s condition deteriorated for the last time.

That had been a bit more than two years ago. Last year Tanjirou had attempted the Kagura but failed after the fifth hour. This time he would either finish or die dancing, on his feet.

He was not even close to ready to give up now. (Was this how Tanjuurou felt in his last year?)

This was no longer a dance. It was sun breathing. It was everything Sumiyoshi had written in his book. And it was one of the few things Tanjirou had left.

As the night went on, Tanjirou found new strength in his body. He found his movements becoming more fluid than they had ever been before.

If not for his complete dedication to the dance and the face-mask he wore, he would have noticed the fire dancing from his sword, melting the snow in an ever-increasing radius, reaching the house more than twenty paces away and melting the snow off the trees surrounding the clearing.

He would have noticed Nezuko flinch on the slashes from the first cycles, before she laid down and rested, basking in the heat the dance emanated.

(He would have noticed the reason why he wasn’t dead yet.)

…

Every hour, Tanjirou felt his steps grow surer. He removed the unnecessary movements he noticed, managing to feel ever more attached to the dance, as if it flowed through him like a burning memory.

He only noticed the sun’s rays touching his skin after doing ten full cycles in broad daylight. The clouds had cleared somewhat, and the dawning sun’s light shone across the landscape.

Tanjirou finally stopped.

Taking off his mask, he realised that Nezuko was gone. Still, he smelled her loud and clear, and, standing still, pinpointed her location exactly through a wall.

As he sheathed his sword, he realised that his hands had gained claws. A quick run of his tongue across his teeth revealed that he had fangs as well. Was he…

As he re-entered the house, the corpses of his family greeted him as they had fourteen hours before. They still smelled like blood. And there was a tiny voice telling him to eat. Tanjirou had become a demon too.

Eat his family. Eat his family, eat Kie, eat Rokuta, eat-. no.no. don’t salivate. don’t look. don’t think.

He hurried over to Nezuko’s sleeping form, hugging her for a minute before grabbing the shovel and starting work on burying the bodies of the people he held dear for his whole life.

Though his determination had not faded, and tears had yet to make their way out of his eyes.

After all, he was the oldest brother. He couldn’t cry. He could only move on, could only leave his family behind.

It’s what they would have wanted.

Chapter Text

Tanjirou was a demon. So was Nezuko. Among the two, it seemed like only Tanjirou could still speak. But Nezuko was still there, she could think, and she had hummed when he told her that they should kill each other if the other ever ate flesh. There could be no excuse for that.

Nezuko still slept. She had shrunk considerably, now only about the size of Rokuta.

Tanjirou managed to clear the house of bodies and blood fairly quickly, and put everything still intact where it used to be, burning everything else in a bonfire outside the home as he prayed for his lost family.

As he was cleaning, he had noticed some small shreds of twine, as if a rope had been torn to shreds and scattered across the floor. He remembered feeing some pain around his wrists and ankles when he had woken up, aside from his bloody wounds. He might have been bound, served as a meal on a platter to be eaten alive by his sister. This man wanted him to suffer at her hands.

Tanjirou was never one to get angry, or to hate.

He was tolerant as could be. He did not even particularly hate people who harmed others, because they could have a reason, some justification, some way they were still human. He was more motivated by the desire to protect.

He was none of that. The image of that man stayed in his mind, as the one person he did truly hate.

How could a person kill a whole family and not bat an eye? How could they hope the survivors were tortured until they died? Tanjirou had always thought of a person as somebody who could choose to do something. This man had chosen his own bloody path, with none to push him. How could he not hate him?

And all-… most of his demons, created from his blood, killed people too. He had seen all the evidence he needed in Sumiyoshi’s book… about how demons had been around Japan, killing people in the thousands since centuries ago, all created by that man. Tanjirou resolved that not only did he need to protect those who could not protect themselves, but also work towards killing him, so that the suffering he caused may not continue.

Nezuko’s struggle was not lost on him. By now he had realised that the first action Nezuko had taken was to bite his shoulder and suck his blood. Though she seemed to regret it later, as Tanjirou could tell by the tears on her face when he had woken up. He was glad that she hadn’t fallen to the curse.

Using his charcoal basket as a container for Nezuko (since she would probably still burn in the sun), Tanjirou set off with nothing more than the clothes on his back, his father’s nichirin katana, and the basket containing his only family.

He did not need to sleep.

In fact, he could not. Not only because it was impossible, but also because every time he shut his eyes he saw the vision of his family dying as he struggled to fill his lungs with air, where he couldn’t do anything, the same way he couldn’t do anything if someone were to harm Nezuko while he slept comfortably, completely unaware. He could not betray her.

So he ate nothing and did not sleep a wink.

And yet he never felt tired.

-

Tanjirou had always felt at ease under the sun.

“Mom, why does the sun feel so good? It’s so warm and nice… I don’t like it when it’s gone!”

“Tanjirou… The sun feels good because it is the source of everything in this world. Every plant, every animal, even every vast sea, owes its existence to the sun. It is why we are grateful to it. Without the sun, we could not live.”

-

Now, every time he walked under the sun, wandering in search of more demons to kill, his body ate the light. This went beyond depending on it indirectly; Tanjirou was sure that without the sun, he would die.

Ironic for a demon.

…

Tanjirou went around, killing demons on sight. His sun breathing and demonic strength alone was enough to slice most demons’ heads off without using any forms.

He could smell demons from miles away. Every time he did, he would run, his still-sleeping sister on his back, reaching the target in less than a minute and ending the job.

He felt much less remorse than he thought he should have.

When a demon kills your family in front of you, something within you snaps.

Every time Tanjirou looked at the slit eyes of a demon, they reminded him of that man.

And so, even though he couldn’t hate those people who hadn’t made the choice of bloodshed for themselves, Tanjirou decapitated them as swiftly as he could, almost like a way to get back at him while still saving them from as much pain as possible.

He still practiced. He danced the kagura every day for at least an hour. Except that instead of dancing, he swung his sword every time with the full intent to kill, leaving felled trees and ground scarred from boiling temperatures in his wake.

…

Six months went by.

Six months in which he did not use a single breathing form against a demon.

Six months in which Nezuko still slept in her basket, her form totally unresponsive but not dead. Hibernating, perhaps?

Months in which Tanjirou honed his skills, to be able to kill demons faster every time he traced their scent; in which Nezuko’s scent shifted slowly, the sourness added by the demonic transformation slowly disappearing as a more flowery scent replaced it.

Months in which the most human contact he had was a blur of colours in his peripheral vision, as he passed by to take out a demon.

He stuck to the forests and mountains, never heading anywhere he could sense humans but no demons.

As he was climbing another mountain, he felt the most foul demonic scent he had ever experienced. It was as if someone had stuffed a rotting corpse under his nose. Nothing compared to his scent, but to his much stronger demonic sense of smell, it might as well have been.

The problem was that mixed in faintly with it was the much sweeter smell of humans. This was urgent. His legs carried him where he needed to go.

------------------------

The group of five slayers made their way up the mountain known as Mount Natagumo.

Their crows had assigned them all the same mission. Made sense, since they had stuck together and bonded for a while before. The group had a perfect track record, but they hadn’t yet faced any big hurdles.

As such, they were inexperienced, despite their years on the field.

The forest started a little ways up the mountain, so before entering, the group stopped and waited a bit to discuss a course of action.

Though as they talked about separating, groups, contingencies and such, and the night deepened, the member of the group with a teal haori noticed a demon walking some distance away.

He called out to the group, and was met with encouragement: “Go on Momoto, lead us!”

They all immediately chased it. It understood that it was in danger, so it increased its pace from a walk to a desperate scramble. Most of the slayers had no trouble keeping up with it, though there was one member of the group who had been injured pretty badly and was still recovering, leading him to fall a bit behind. They could not wait for the straggler.

The demon slowly but surely lost ground, and the slayers were hot on its tail.

Finally, the demon stopped before a house, cornered due to the little room left for it to manoeuvre. The slayers stopped too, for a different reason.

They noticed a second demon, taking the form of a boy with white hair and skin, perched on top of the house. It had a commanding all the way up there, but for the moment they thought they were safe. Wasn’t it five against two?

“Hey. Do you want to be saved?” it asked. “If I help you, will you do what I ask of you?”

“Yes, please save me! I’ll do what you want!” responded the demon waiting in the clearing. Momoto was getting impatient. He readied his blade again.

“Join my family.”

“Yes! I’ll do it!”

Momoto interjected: “What are they talking about? Say your prayers, demon.”

But before he could even move, silver threads of spider silk whipped across the clearing in front of the house. The slayers had no time to react, but a green and red blur presented itself. It whipped through the clearing, severing every thread.

When the blur came to a stop, behind the demon on the house, all eyes turned to face it.

It was a man… no, a boy, no, a demon? with a green and black checkered haori and a basket on his back. A mark resembling flames was on the top-left of his face. His eyes and hair were both a deep red, and his eyes seemed to glow in the night’s darkness. A sheath was strapped to his waist, and a sword was held firmly in his hands.

The new participant spoke: “Leave now, slayers. I don’t want to put you in danger.”

Before any of them could react, the white-haired demon shouted: “Family! Come out!”

The other demon left on the floor was decapitated by Momoto, who then led everyone back warily. It was obvious that the demon had called for support (however unlikely it was that demons were working together). This could well be what killed them. Every member knew the risk.

The sound of running, some steps light and others much heavier, reached the clearing. Soon, seven more demons, most of them with similar patterning to the one on the roof, burst into vision.

The boy with the checkered haori vanished, leaving a trail of red-orange flames leading down to the centre of the clearing, keeping everyone’s attention.

“Well, well, well. What do we have here?” one of the other demons remarked.

The boy stayed silent. He made a stance, back turned to the group of slayers.

The demons pounced.

The boy weaved between the blows, slicing an arm off the bulkiest demon. As the boy stopped, the battle fell to a standstill again.

The roof demon jumped down from where they were standing, and made their way over to the bulky demon. And slapped him. “Father! You cannot lose. Protect our family! It is the duty of the eldest to protect the younger ones.”

The boy finally spoke again: “What is the value of a family to you?”

Everyone fell silent.

The roof demon responded first: “Every member of a family must protect the ones younger than them, and everybody must care for each other.”

“If you are family and care for each other, then why are the only feelings I smell from this group intimidation and desperation? Your bonds are fake!”

With that, the boy launched himself back at the group, fire in his eyes.

Sun Breathing, Ninth Form: Sun Halo Dragon Head Dance.

His trail, presenting as a red streak, avoided every attack, and was only stopped by a grid of bright red threads blocking his passage to the demons. The roof demon’s blood demon art, probably.

The attack terminated early, and the boy switched to a different form.

Fourth Form: Burning Bones, Summer Sun.

The webs were mostly cut, but the boy dodged out of the way of a stray few, retreating towards the watching slayers.

He prepared for another attack.

Though, as he did this, several things happened simultaneously:

1. A headless beast holding two blades burst into the clearing.

2. One of the demons, the one that looked like a spider with a man’s head, spit some purple liquid at the boy.

3. The largest demon started shedding its skin.

4. Several large spider-like creatures with human faces charged at the boy.

The moment the boy took a single step forward, red threads seemingly rained from the sky.

Sun Breathing, Eleventh Form: Parahelion Rainbow.

Every attack sliced at thin air, as the boy seemingly vanished.

He reappeared on the other side of the clearing, with his back to the house.

The attacks kept chasing him, but he nearly effortlessly dodged, still getting blocked by red threads every time he so much as tried to approach an enemy.

And then the unthinkable happened.

“I should better get rid of these pesky slayers, hmm?”

Red threads shot out towards the slayers, who immediately turned and ran.

They caught a blur of green and red out of the corner of their eyes.

------------------------

He had done it.

Why had he targeted the bystanders? Why did he abuse Tanjirou’s kindness

Time seemed to freeze, as Tanjirou beelined for the slayers, cutting straight through the group of demons.

The roof demon was too far to attack directly, so the only choice was to take out the threads themselves.

Sun Breathing, Sixth Form: Solar Heat Haze.

Tanjirou knew too well that even the extended range of the attack would not be enough. He focused entirely on willing the form to go further, even if just by a little bit.

As red threads touched the hair of the running slayers, and several attacks got aimed at Tanjirou and the basket on his back, he still tried to reach.

It was the only thing he could do.

Hope that he could save these people.

It wasn’t always possible. This wasn’t his first failure.

Chapter Text

It had been another day and night of travelling since the last mission, during his fifth month since the atrocity.

Tanjirou had smelled a demon and a human, in close proximity. In the same house, even.

He had found them near a cabin in the woods next to a small town.

Trusting his speed, he had decided to watch the event from a tree nearby.

A brother and a sister (by the similarity of their scents) sat together, in a clearing. They were talking. The boy was a demon, while the girl was human.

Judging by his scent, the boy was not a strong demon, maybe having eaten just enough to regain his original intelligence.

Tanjirou watched and listened to the two, as they laid down and watched the stars together.

Maybe the bond was genuine. Maybe after becoming a demon the boy still understood and loved his sister. The smell wafting through the air was one of quiet contentment, from both sides.

Were they like Nezuko and me?

But this demon had eaten. He decided to continue watching.

Thirty minutes passed, mostly filled with silence, as the two siblings stared up at the sky. It was truly peaceful.

Then, a demon slayer showed up.

“Demon! Get away from that human!”

And Tanjirou watched the child get up and walk towards the demon slayer, as the demon took position across from them.

As soon as the demon slayer’s attention was fully focused on the demon, the girl, without missing a beat, slipped a long knife through the slayer’s ribs, and pushed, presumably puncturing the heart.

A reminder of man’s cruelty towards man.

Even as Tanjirou jumped to save them, it was too late.

The slayer had swung their green blade at the sister in a heartbeat, decapitating her. And the slayer himself had collapsed onto the floor, his heart irreparably damaged.

Tanjirou made it an instant too late to stop the wind breather.

And now two people had died.

He stood facing the brother.

“I know that your relationship with your sister is true. But I cannot forgive you both for the tragedies you have caused.”

Tanjirou disappeared, and the brother’s head fell to the ground with a dull thump.

Behind him, Tanjirou put his hands together and muttered a prayer for the three souls who had perished that day.

He had failed to save two people.

But was the sister one to be saved?

She killed, too. Did she deserve any more compassion than the demon, who needed human meat to survive?

It’s easy, as a demon slayer, to forget that humans can commit evil too, since it’s not their job to prevent it. Too easy.

------------------------

Tanjirou did not notice as Nezuko stirred in his basket for the first time in six months.

As she came to her senses, she peeked out and saw the battle. Tanjirou’s desperate run, the attacks set to destroy them both, and the red threads heading for the slayers.

And she saw Tanjirou trying his best, sacrificing himself to protect others.

In that instant, she wanted nothing more than to help her brother save people. She saw the bad red threads, and wished that they’d burn.

As attacks hit her brother and both their bloods were spilled, it finally clicked, how she could do it. How she could help him.

Blood Demon Art: Blood Burst!

Despite the large distance left to cover, Nezuko, burning nearly a third of her body’s blood, managed to reach the threads.

Though some got through and scratched the slayers, they were mostly fine.

And Nezuko was not the only one who had become a bloodied mess while trying to save the slayers.

Tanjirou had lost his head in a slash from the back, and his left arm had turned to mist from a punch from the fully-recovered ‘father’ demon, who sported a larger form now that his transformation was complete.

Except that instead of falling to the ground, his head floated in the air, connected to his body with a stream of bright red blood. His grip on his blade only got stronger.

Some poisoned liquid shot from the spider brother hit his torso, burning it. Tanjirou pushed through.

He could not give up now.

The attack had been stopped, but the battle was not yet won.

His own attack completed, Tanjirou whirled around to parry each blow that continued to come his way, his head slowly reconnecting to his body and his arm’s bleeding stopping.

He eventually was pushed out of the range of all of his enemies, suffering a few more hits due to his severed arm.

The basket destroyed, Nezuko stood next to her brother, completely drained but still on her legs due to sheer rage.

How dare they hurt my brother?

Tanjirou stood prone, watching as the sun peeked out behind the mountains, lightening up the sky.

The spider ‘family’ immediately ran as they noticed, tripping over themselves as they entered the house or scattered into the woods.

Tanjirou grabbed his sister and took her to a cave he had seen on the way there, leaving the slayers behind. Nezuko was sheltered from the sunrise. She collapsed on the stone floor, asleep.

------------------------

The siblings had by no means come out of the battle unscathed. Tanjirou’s haori was ripped in several places where he had let attacks through, and his shirt was dripping blood onto the floor, not to mention his severed arm.

At least his wounds were slowly healing. All his bleeding had already stopped, and the skin on his torso started covering the muscles exposed due to the acid attack. Nezuko’s injuries were still very bad, but she had not lost any limbs, only blood. From how pale she looked, Tanjirou was surprised she had even been able to stand. Her skin was deathly white, the veins under it not showing any colour at all.

As Nezuko slept in the cave, Tanjirou walked back out, drinking up the sun’s rays and feeling his cuts and bruises close up, the weight on his left side slowly increasing.

As for Nezuko’s blood demon art…

She seemed capable of controlling the target of the pink flames that had erupted from her wounds. Tanjirou had not seen her activate it, but he knew enough about blood demon arts and that battle to reason that it could not have been anyone else who did it.

The slayers had been targeted because the other demon had realised that the sun was coming up. He needed to end the battle soon, so he had elected to cut his losses against Tanjirou and make a move on the bystanders.

It had worked better than the demon had expected. After all, he had not known of Tanjirou and Nezuko’s desires to protect others, even to the point of sacrificing themselves.

As Tanjirou lay down in the sun, he smelled the slayers approach again. Looking down at his feet, he saw all five of them, cuts on their faces from the red threads, come closer, step by step. He stared back up at the blue sky.

“He can walk in the sun?” was the first thing he heard.

Then, “What do we do with him? He’s a demon, we should kill him. But he helped us…”

Without warning, a blade slashed from his left side, decapitating him from his side that had no defences. His own blade had been left in its bloody sheath back at the cave. It was the slayers’ choice to make. The only regret he had was that Nezuko would be left alone.

His neck was severed painlessly, as he laid down in a grassy field, staring peacefully up at the sky. The attack’s blue trail, signifying a water breathing swordsman, faded away in the light breeze.

At least he would not die failing to protect someone.

Except that he did not burn. His head simply reconnected.

“HUH?”

The slayers erupted into a cacophony of noise.

Over the next minute or so, Tanjirou managed to fully regenerate, save for his left hand, which was still missing.

He got up.

“Hey there!”

Reminding him of the scene at the house, all eyes snapped to him, and silence fell.

“You’re demon slayers, right?”

“Guys, I don’t think we can do anything against this demon, so we might as well hear it out,” decided the boy in the teal haori.

“I’m Kamado Tanjirou! Nice to meet you! The one who made the pink fire is my sister, Nezuko!”

“Since you’re a demon, I want to ask: Why are you killing demons? Why are you protecting us? Most demons would have attacked us by now.”

Tanjirou faced the man with the teal haori. “I have a personal grudge against the demon progenitor. He killed my family… My sister and I were the only survivors. I wanted to protect others from similar tragedies. Neither of us has tasted flesh, and we never will. Do you trust us?” Please do…

The boy replied quickly. “I don’t. But I will agree to never talk of it, since it seems you are doing good. Goodbye.”

The slayer turned away.

“Thank you.” Tanjirou bowed.

They walked off, and Tanjirou waved at their shrinking forms. He laid down on the soft grass, savouring the sunlight once again.

Chapter Text

Tanjirou should have thought of disguising himself sooner. Sometimes he really was forgetful, especially without Nezuko to remind him…

It was pretty obvious that he was a demon from his claws and fangs, and unlike his sister, whose eyes had returned to normal when outside of battle, Tanjirou’s were still slitted and glowed slightly. He washed the blood out of his clothes, looking at his reflection in a small stream, seeing how he had changed.

He would have to do something about his appearance, just in case he wanted to be in close proximity of humans. And if he wanted to continue killing demons, he would be guaranteed to see more slayers anyway.

He decided to rely on his other amplified senses, and closed his eyes. He could probably make up for his impaired sense of sight, but Tanjirou still felt the loss of perception badly, having neglected training with eyes closed back when he was human, even though his ancestor’s book had explained it. That would have been useful…

He also tightened his blue scarf around his neck, and pulled it up to cover his mouth. For his hands he could not do much, only hide them by balling them tightly until he could find a pair of gloves. He would have to go to town to get a new basket for Nezuko anyway. He would buy gloves while there.

He checked how he looked in the reflection on the stream, by opening one eye. Oops… he had forgotten about the tears in his clothes, he would need a needle to sew it, and for his purchases, he would have to pick them up with his clawed hands…

No, he would probably need a human contact to do the purchases for him, since his current look… would raise too many questions.

Returning to the cave, he tucked Nezuko into a corner, folded her haori, and set her head on it.

Grabbing his sword and the little money he had saved, he tracked the slayers down. They could probably help him.

Appearing next to the group of five, he spoke to the slayer in the teal haori: “Hey, could I ask a favour of you?”

The whole group jumped in surprise (was he being too silent?), and four swords were unsheathed. The boy in the teal haori had vacant eyes as he turned to face the newcomer. “Go on.”

“I can’t go around looking like this, so could you please go to town and buy some things for me? I hate asking for help, but I have to. I have the money.”

“Hmm…”

“I’ll give you all my money! Keep the change! I need a basket, a sewing needle, a spool of string, some white cloth, and a pair of large gloves. Is that OK? Sorry…”

“Fine, but only for the spare money.”

“Thank you very much.” Tanjirou bowed, gave him the money, and continued to follow the group.

“Is it OK if I stay with you until you make it to town? I could stop somewhere nearby, and wait for you.”

“No. It’s better if we part now, and meet later. I don’t want anyone seeing us with you.”

“Also fine! I can find you when you leave the town, just wait for me! Again, thank you for your help.” Tanjirou bowed again, and disappeared.

…

In the end, he managed to get everything he needed by sunset, and headed back with the supplies. The slayer he had talked to was pretty helpful, and really seemed not to care about him being a demon after their first interaction, even though everyone else had their swords drawn for the whole conversation. Tanjirou was grateful.

Once back in the cave, he immediately started work on mending the clothes, going out and washing any blood out then sewing up the cuts and holes.

Nezuko woke up halfway through the process, and started helping too. Her sewing was much slower than when she had been a human, since her hands shook as she handled the needle and thread, but she could manage.

By the end of the night, the clothes were mostly repaired. Nezuko had gone back to sleep, and Tanjirou was putting the finishing touches on their clothes. He was done by noon, and put Nezuko in the basket, ready to hunt demons.

------------------------

Kaigaku had managed to get to Final Selection. His cultivator had finally let him, after more than two straight years of training.

At least he had done it before his talented little brother that brat. Jigoro favoured him so much, yet all he did was whimper and whine. Kaigaku had no idea what the man saw in that idiot.

He was climbing the stairs together with a strange boy who walked with his eyes closed. He had a birthmark that looked like a red flame on the left side of his forehead. Kaigaku could not help noticing that it was very large and notable for a birthmark.

His scarf covered his lower face, and he wore large leather gloves, that were surely too big for his hands given his age. It seemed like he was trying to hide something… he wasn’t a demon, somehow. That much was obvious from his walking in the sun right between wisteria trees (if Jigoro were to be trusted).

As they both made it onto a platform full of more good-for-nothings like Zenitsu, who were quivering in their boots at the thought of the Final Selection, he looked back at the mystery boy, who had frozen in place and seemed like he was listening to what everyone was saying.

“My cultivator told me that I was ready, but… now that I’m here, I’m not so sure. Should I go back?”

“I’ve seen a demon before. Th- THEY’RE NOT SCARY, OKAY?”

“I don’t have what it takes to become a demon slayer.”

At that last statement, the boy seemed to relax. He sprinted down the steps. Maybe he chickened out too.

Kaigaku sighed. So much for having a single person with balls in this Selection. They would all die or get lucky. Not a single worthy slayer in the Corps these days… hadn’t he overheard that from Jigoro

…

The boy came back. Maybe his cultivator came and ushered him back up the mountain. Who knows.

…

Two children came into the clearing, standing in front of the gate leading up the mountain. They looked hauntingly similar: Their height, purple eyes, faces, body shapes, and purple clothes with green sashes were all the exact same… except that one had white hair and the other had black.

They spoke sometimes in perfect unison, and sometimes alternating, reciting a perfectly rehearsed speech:

“Greetings, candidates. Thank you for attending the Final Selection. Here on Mount Fujikasane, there are demons trapped by the Corps. They cannot descend the mountain. This is because wisteria, a flower demons cannot stand, blooms year-round on the mountain’s lower half. There is no wisteria beyond this point, so demons will be present. To pass the Final Selection, one must survive for seven days, and return to this point.”

“And now, be on your way.”

Kaigaku and the mystery person went through the gate first, followed by the other ‘candidates’.

The boy just… vanished without a trace.

No sound, no nothing. It was like he was never there.

A few seconds later, Kaigaku was ambushed by a demon.

…

After the first night, the number of demons he encountered steadily declined.

The first night had him fighting five demons. He ran away from three, and killed two.

The second night had two. He killed both.

The third night had zero.

Until the fifth night of the selection Kaigaku did not encounter even one other demon. He started wondering if the mountain had been completely emptied already.

That night, he found himself face to face with a large, grotesque demon. It was green all over, and seemed to be formed almost entirely of large hands.

He saw the demon consume a dead candidate with a single swallow.

This was a fight he could not win. Even the strongest warriors must understand when to cut losses, he thought.

“Ooh, another candidate? They just keep coming, don’t they?”

It reached out with six hands, four from the left and two from the right, trying to grab him. He almost failed to dodge, and the wind from the passing hands moved his hair. When he tried to run away, forcing his oxygen into his legs, he was blocked by several arms erupting from the ground, followed by a mess of flesh heading towards him. No no no no no-

“STOP! PLEASE, I’LL DO ANYTHING!” …

Sometimes it’s necessary to grovel to save one’s life.

The hand demon hesitated.

“I’ll do anything… I can send you the other candidates, I’ll feed them to you… just spare me, please!”

The demon seemed to have seen something in Kaigaku. Maybe it saw that Kaigaku was being perfectly sincere. After all, he would send the other candidates to their deaths without reservations, just as he had condemned his own family because they didn’t deserve to pass, and it was all the hand demon’s fault, none his…

“That would be acceptable,” the hand demon said, retracting its attacks.

“Yes. Thank you for sparing me.”

The demon reached out with several hands, surrounding him.

“Remember what happens if I don’t see more candidates. I’ll find you, and I’ll kill you.”

All the hands retracted.

“Alright, go ahead. Oh, also, if you see any little foxes, make sure to send them to me. I’ll stay here for a bit.”

Kaigaku walked off, relieved.

Could the hand demon actually catch him? Who the hell cared. He increased his pace and looked for more people.

It wasn’t long before he found some. Each of them he took with him, promising safety and protection.

A short boy with white hair and dark clothes. Kaigaku would probably see his face of absolute betrayal in a nightmare. Maybe.

A girl with a ponytail of black hair, with a pattern of stripes on her haori. She died fighting, as her sword got stuck in the demon’s neck, snapping in two with a loud crack before she was killed. Kaigaku didn’t bother to watch.

And then, the same boy as before, with a serene look on his face as he weaved through the trees.

“Hey there.”

“Hello!” A muffled but energetic voice replied.

This was the first time he had heard the boy speak. He stopped in front of Kaigaku.

His haori looked a bit scuffed, and on closer inspection, there were several seams where the cloth had presumably been torn and repaired, tracing claw patterns along the cloth. He didn’t seem to have any luggage whatsoever, so those repairs must have happened before.

Kaigaku hesitated. This person seemed at least fairly competent. The others he did not care about; they were worthless from the start. This one had probably survived injury by demon already.

But Kaigaku didn’t hesitate.

The way the boy’s eyes were closed while he still was fully aware reminded Kaigaku of Zenitsu.

He had seen it happen once. Kaigaku had hit Zenitsu on the neck with his blade during a sparring session. He should have fallen down, unconscious, but instead, he stayed on his feet, unwavering, in a perfect stance

Every trace of cowardice was gone from that idiot when he was in that state, and he had almost struck Kaigaku several times until he woke up.

Awe-inspiring Unacceptable.

Kaigaku was jealous of him He was probably a wimp too, behind those shut eyelids.

Putting on a facade of altruism, his smile not quite reaching his eyes, Kaigaku continued:

“I know of a place where the demons can’t go, it’s safe there. I set up a camp. Should I take you there?”

“Ah, don’t worry, if it will stress you I’m fine!”

Damn this kindness!

“Please, it will be OK. I want to look out for you, is all.”

“Thank you then! Hmmm… I’m Kamado Tanjirou. What’s your name?”

“Kaigaku.”

“No surname?”

Kaigaku nodded.

“Follow me.” They set off in silence.

…

“Hey… I smell a demon. It’s right up ahead. Should I take care of it? It could be threatening your camp!”

Smell a demon? Was his cover really blown this easily?

“Alright, I’m going!”

Whatever. He would die like the rest.

He disappeared again. This time, Kaigaku saw a flash of red.

Soon, a booming voice could be heard:

“Ah, look who we have here! Another puppy brought straight to me! I have to find a way to thank you later, Kaigaku!”

Kaigaku flinched.

A softer voice:

“I saw a demon and a human collaborating once.”

Some loud thumps were heard. Kaigaku slowly approached the pair.

“They were siblings, bound by blood.”

The clang of steel against rock (or an equally hard surface).

“The sister would lure slayers in, and kill them for her brother.”

Kaigaku got close enough to hear the gusts of air, but not see the attacks.

More clangs of metal sounded.

Then came the cracking of bones. Kaigaku almost winced.

He saw the battle take place in front of him.

The boy had been sent flying into a tree, and blood stained the floor beneath him, as he sank to his knees, his eyes still closed. Was he that strong Was he blind?

Another dead to the hand demon. Kaigaku really wondered why the weak would try to fight the strong.

The hand demon hesitated a bit, then picked up the fallen slayer, and threw him through another tree. He landed on the floor, but this time, picked himself up as if not injured.

“I forgave the brother more than the sister, but you are worse than both.”

A red flash came towards the demon, but stopped just short.

“Haha. You haven’t killed… me?”

The demon’s head fell forwards. Its body stayed upright, but started turning to ash.

Kaigaku thought he heard the word ‘hold’.

Tanjirou held one of the disintegrating hands.

As the demon completely disappeared, Tanjirou turned his head to look straight at Kaigaku.

His eyes were still closed.

Kaigaku did not know if he was imagining it, but Tanjirou’s birthmark seemed to have gotten slightly more intricate.

“Kaigaku.”

Kaigaku stayed silent.

“You helped him, Kaigaku, you killed people… I can’t kill you, I don’t know what to think. Bye.”

With that, he vanished again. Gone without a trace, like the dead demon whose ashes still floated on the wind.

He thought he heard Jigoro scold him again. ‘Beg for forgiveness, not mercy, Kaigaku.’

The time to change things was past. Kaigaku had made his choice the moment he stepped foot in the Final Selection arena. He didn’t need forgiveness.

Chapter Text

As the two children had said, surviving candidates had to make their way to the starting platform by dawn on the seventh day. Tanjirou could deal with the wisteria on the mountain in sunlight – his lungs regenerated fast enough that he didn’t feel significant pain.

However, at night…

Tanjirou was coughing constantly as he walked onto the platform. The six other people there, excluding Kaigaku, looked on in concern. Kaigaku looked at Tanjirou with what looked like derision.

Blood stained his scarf; he would have to clean it later. He had already cleaned the rest of his clothes in a nearby stream. Dawn would come in less than a minute, so Tanjirou was not too concerned.

Struggling to remain on his feet, Tanjirou tried to keep growling and hissing out of his voice as he continued to cough, his lungs slowly destroying themselves.

A girl came forward and asked if Tanjirou was fine.

He couldn’t say why he was coughing. Lying was wrong, he could not do it. Besides, he could not speak in this state anyway.

So he did not speak, sinking to his knees as his body’s reaction to the wisteria took its toll. Blood started dripping from his scarf.

Then the sun came up.

His coughing almost instantly ceased as the sun touched his skin. Tanjirou stood upright immediately, and waited for the selection to conclude.

The girl had an incredibly confused expression on her face, as she stepped away. Tanjirou thought that he might have accidentally exposed himself. However, she made no comment, and her scent did not carry much suspicion.

Just a few seconds later, the same two children as before emerged from the wisteria, went to their previous positions and gave another speech. Tanjirou realised that they had barely any scent at all; that, or they smelled a lot like wisteria.

“Welcome back. Congratulations. We are pleased that you have returned. First, you shall choose the ore used to forge your own nichirin blade.”

They removed cloth from a table, exposing several chunks of ore, telling the surviving candidates to choose one each.

Tanjirou sniffed the air, then chose the one that smelled a bit like charcoal. The scent was very faint, to the point that Tanjirou thought he was imagining it, but he had no real way to tell. They all looked mostly the same, anyway. The Transparent World did not exactly help classify rocks.

Speaking of the Transparent World…

-

Tanjirou relaxed in his room after a long night of training.

They had found the book Tanjuro had referred to, and read it together. It spoke of a man called Yoriichi Tsugikuni , the strongest demon slayer in history.

It mentioned how Sumiyoshi intended to pass down his technique, which was called Sun Breathing. Every form was described in meticulous detail, allowing for Tanjirou to refine the family kagura into something more resembling Yoriichi’s Breathing.

That day, he had read the segment that spoke of what Yoriichi had called the Transparent World.

How slayers with the mark had managed to see through skin like it was glass.

But he was not marked. He was not worthy yet.

So he trained.

…

When he entered the Final Selection accidentally, smelling demons mixed with the painful wisteria, he had resolved to always fight with his eyes closed and his regeneration turned off when he could.

Even though becoming a demon had improved his other senses, Tanjirou’s sight had guided him nearly totally. He had neglected that aspect of his training.

So why not start now?

It all worked fairly well, until he met that hand demon.

Tanjirou had realised that he was on the cusp of some grand revelation. He had already realised that the mark on his forehead resembled an illustration the book had of Yoriichi’s own. Yet he had this not because he deserved it, but because he was a demon.

So he focused on calming down, entering a state of battle-readiness and perceiving his surroundings as best he could.

He managed to parry several blows, but eventually got caught.

After all, his sight guided him.

As he got beaten up, he focused on seeing .

And he saw.

His own eyelids, followed by the demon’s skin, became transparent.

And all he needed was one strike. One form. Solar Heat Haze ended the battle.

Was it really a battle if he was holding back? Was it too easy ? Maybe.

-

Kaigaku went next, puffing up his chest a bit as he selected the ore closest to him.

The rest of the candidates went, one by one.

Once all the ore had been selected, uniforms were measured.

Tanjirou had to refuse to remove his gloves and scarf, for obvious reasons, but the ‘kakushi’ taking the measurements just remarked on it and let it be.

However, when it came to engraving ranks…

“Kamado-san, can you please remove your gloves? We need to give you a rank on the back of your hand.”

“Sorry… Could you do it somewhere else? Like on the forearm?”

“It’s not conventional… but there isn’t really a rule saying we can’t.”

The engraving of the rank itself was pure agony, since the active ingredient was concentrated wisteria, and it was being tattooed deep into his skin, mixing with his blood. Tanjirou was sure he shattered some of his teeth while trying not to scream. He willed his regeneration to stop, as the needle etched its mark on his skin.

After what seemed like an eternity, it was done.

Tanjirou did not allow the scratches to close, though he thought he couldn’t have even if he tried.

“Strange. The scratches are still bleeding. It should have at least clotted by now. Unusual… Anyways, to see your rank you just have to expose your ha- forearm and say ‘show me my rank’.”

He tried it and the kanji for ‘mizunoto’ flashed on his skin.

But it burned so bad.

Still, it was part of the process of being a demon slayer. He could not refuse.

Finally, everyone got their Kasugai crows, for communication and mission assignment.

Tanjirou got a pretty ‘normal’ crow, all things considered. Even though the female crow could talk, she was respectful, and he only noticed her presence when she made herself known. He decided to name her ‘Shou’.

------------------------

Nezuko woke up in a cave.

A small cave, all things considered. For protection from the sun, no more.

Tanjirou had told her to stay here for a week. She would.

So she sat and waited.

And waited.

It turned out that a week was a long time to sit around doing nothing. Nezuko did not have much to do anyway. The sewing kit was still with her, so she played with it a bit, since no clothes were left to mend.

She decided to sleep away the rest of the week, dozing off after about an hour.

…

She woke up.

Someone was patting her head.

As she opened her eyes, she recognised Tanjirou.

Finally!

She pulled him into a tight hug. However, she also smelled some blood, and noticed the scuffs in his clothing. Had he gotten injured?

He, sensing her concern, showed the inside of his scarf. He told her he was fine.

Nezuko bottled up her concern, but still worried for him. He could not go around getting hurt.

Apparently the stinging smell in the air was ‘wisteria’. He had walked through it, and it had destroyed his lungs without the sun healing them.

Nezuko’s own regeneration thankfully worked well at all times of day, but wisteria had a greater effect on her.

They left the cave behind. Nezuko had only really been aware for about two hours of her stay. She was not attached.

Tanjirou explained that he had gotten a crow, who now followed him and would direct him to demons, once he received his sword. It was very cute! Nezuko almost immediately grew attached to it, stroking its little head, limiting her immense strength to no more than a touch.

They set off to new horizons.

Chapter Text

Though it would have been nice to slay demons without concerns, Tanjirou knew that that man might have wanted to attack himself personally. After all, he was pretty sure that the demon progenitor had some sort of vendetta against sun breathers. It made sense, after what Yoriichi had done to him…

And now that he had shown himself…

If those spider demons had reported back, then that man might have sent more demons after him, or started tracking Tanjirou himself.

So he would have to stay vigilant.

Thankfully, his doubly enhanced sense of smell and the Transparent World would help significantly with that.

However, there was not really that much that Tanjirou could do to stop his being tracked.

Of course, this was all speculation. But Tanjirou did not want to become acquainted with him again.

He had already read about what had happened when Yoriichi and the Demon King had fought.

Tanjirou was no Yoriichi. Not yet, at least. And besides, the Demon King would have gotten stronger in the hundreds of years since Yoriichi’s death.

And yet, he had still been scared back at the Kamado house. The scent was unmistakable.

…

Tanjirou’s uniform and sword had to arrive for him to truly become a demon slayer. Then, he could also stop using the ancestral blade, and finally lay it to rest.

Though, considering Tanjirou’s nomadic wandering for the last six months, he doubted that whoever was delivering would be able to find him. Maybe his crow would have something to do with that? She had been following him for a while, so it would make sense.

So he camped out in a cave for a while, running patrols out of it, and getting a few demons here and there. Shou had eventually left, and returned about a day later. She just told him to stay put.

After nine days, his swordsmith arrived.

“Hello!” Tanjirou called out.

The swordsmith walked towards him, the wind chimes hanging from his straw hat making soft noises in the breeze.

At last, he arrived at the mouth of the cave.

“My name is Haganezuka Hotaru! This is a nichirin blade. I forged this blade for Kamado Tanjirou.”

“That would be me!”

“It is made from Scarlet Crimson Iron Sand and Scarlet Ore, materials only possible to obtain at the peak of one particular mountain.”

He rambled on for a bit, and since Tanjirou could not really provide accomodation for him, they just stood facing each other for the better part of three minutes (and Tanjirou learned a lot more about the swordmaking process than he thought he would ever know), and Tanjirou attempted frequently to interrupt him, but the swordsmith kept talking, until he suddenly looked up. He was wearing a wooden Hyottoko mask, which almost made Tanjirou giggle despite the circumstances.

“Oh? You might be a child of brightness. This is very lucky.”

“I’m the child of Kie and Tanjuurou, not of brightness.”

“That’s not what I mean. Whenever a child with red hair and eyes is born in a family that works with fire, they are called children of brightness, and are considered a good omen. Your hair is red, but your eyes…”

That would line up surprisingly closely with reality. Did this concept come from Tanjirou’s ancestors? Maybe even Yoriichi himself? He was not sure.

“Really? I didn’t know about ‘children of brightness’.”

“There is a good chance this blade will turn bright red.”

Tanjirou had seen just one mention of a bright red sword in the book. How a sword could turn bright red if it was hot enough, and enough battle spirit was being channeled through it. Could it be that he was referring to?

Haganezuka opened the box he carried, and removed a sword in a black sheath. The handle was black and red, and the handguard was composed of two concentric circles connected by thin strips of steel, like rays of sun.

Tanjirou accepted it and unsheathed the blade, feeling its weight and grip through his gloves.

The gray of the sword almost instantly turned pitch black.

“Curses! I won’t be able to see a bright red sword after all! Black swords are cursed!” Haganezuka started uttering a stream of nonsense about how Tanjirou would be cursed for the rest of his life, and inched himself closer to him, working himself into a rage.

It was not nice seeing this person in this state. It was childish, to say the least.

“Wait… How old are you?”

“37!”

He continued rambling, looking at Tanjirou’s legs and fidgeting.

Tanjirou thought that maybe he could make his sword bright red, by preparing Sun Breathing without using any forms. After all, he might have been marked. He was still not entirely sure.

As he breathed, he watched the base of his sword turn a bright red, slowly creeping up the blade.

“Haganezuka-san?”

He continued rambling.

Tanjirou tightened his grip.

“Haganezuka-san!”

He finally glanced up.

The swordsman froze. Through the Transparent World, he noticed that the swordsmith had stopped breathing too.

“FINALLY! MY LIFELONG DREAM!”

He stared in awe as Tanjirou stood perfectly still, his sword nearly half bright crimson.

His eyes started glazing over.

“Haganezuka-san, breathe!”

He collapsed. Tanjirou sheathed his still-red blade and caught his swordsmith by the armpits.

Okay…

…

Tanjirou had accomodated for the swordsmith in the cave, using his and his sister’s clothes as blankets. When he had woken up, he had been nearly in a frenzy, but Tanjirou had managed to calm him down, using some of the techniques that worked on his younger siblings. One of them was tickling. It had worked surprisingly well.

Thanking him for the sword as Haganezuka gave him the uniform still tucked in his luggage, he had seen his eccentric swordsmith off.

The first mission arrived by crow.

Slay a demon that had been sinking boats in a lake. He would be joined by two other slayers for the mission.

It was supposed to be mizunoto-level.

With Nezuko on his back, his new uniform worn under his haori, and his eyes still shut, he sprinted to the mission, which was straight west from where he had been.

…

As chance would have it, Kaigaku had been sent to the very same mission.

------------------------

Kaigaku had very nearly considered just never coming back from Final Selection, to be able to forget about that brown-haired brat Zenitsu for the rest of his life.

He still wanted to see his teacher again, if only to try his hand at the first form of Thunder Breathing for the ten thousandth time. Maybe Zenitsu could help him too

As he walked through the peach orchards he saw Jigoro coming towards him.

“Jii-san, wait for me!”

A blonde boy followed close behind.

Blonde?

Was Zenitsu blonde now?

Did it strike some sense into him?

“Hello, aniki! I was so scared for you! Thank goodness you’re back!”

Zenitsu’s eyes watered.

Still a wimp. Sad Disappointing. Dirt like him had no business living with Kaigaku and a former hasira. It was an embarassment.

“Aniki, I got struck by lightning! It was so scary! I thought I was dead! And then Jii-san saved me!”

Wish he hadn’t gotten hurt died. Oh well.

…

Two more weeks of spending time with hating Zenitsu. That’s what happened until his sword arrived and his first mission was set.

Three slayers. Mizunoto level.

No problem.

------------------------

Tanjirou shouted eastward: “Hey, Kaigaku!”

Through the Transparent World, Tanjirou saw him still deep in the forest, his previous, relatively happy disposition vanishing in an instant as he heard Tanjirou call his name.

It was already sunset at the bank of the lake. It was one of the best landscapes Tanjirou had seen. The surface of the fresh water was like glass, allowing for Tanjirou to see his own reflection for the first time in a long while. His mark had gotten a little bit bigger, and he could see a smaller mirror image of it peeking from below his chin, on his right.

A girl had already arrived. She had long black hair she tied into a ponytail. Her hair reminded him of Nezuko’s back when she was human.

They had talked for a bit.

She wore a blue haori to represent her use of water breathing. Appropriate, given the situation. Tanjirou knew that he would have to try harder to match her, since they were presumably going to fight in the lake.

She had not lost family, but had witnessed a demon attack and cowered and hid defencelessly until the sun rose and the demon ran away. She had wanted to fix her weakness.

Apparently her cultivator had been very secretive, and banned anyone from using their name. She had been the one at Final Selection who approached Tanjirou when his lungs were tearing from the wisteria. He had seen her behead a demon in the arena before that.

A capable slayer for this mission.

A demonic scent lingered over the whole lake, covering it like a blanket. It was not really possible to pinpoint the demon’s location exactly. Tanjirou decided to plan now, and wait until night to attack.

…

Kaigaku finally made it to the clearing.

“Oh. It’s you again,” he said.

“Kaigaku! I hope we can work well together, even if we’ve not been on the best relations so far.”

“Hmm… Girl, what’s your name?”

“Nakashima Natsuko. I use water breathing.”

“Figures. Want to use this boy here as bait for the demon?”

“N-no, why would-”

“Sure!” Tanjirou exclaimed.

“What? Why would you agree to that?” the two others said, nearly in unison.

“I don’t want to get others hurt, so I’ll offer myself. Don’t worry about me. I’ll swim near the shore and attract the demon. We can take them together from there.”

The girl worried: “And if you die because of us? I don’t want anyone to have to sacrifice themselves.”

“Please, don’t worry. I’ll be fine.”

As night descended, Tanjirou removed his haori and placed it on Nezuko’s basket. Beside it, he placed his own sword.

He had left his father’s sword, which had been passed down and maintained as an heirloom, close to his father’s grave, since the Kamado household was on the way. He had taken care to secure it tightly to the gravestone, and buried it under dirt.

He had also repaired some of the damage the house had received during the attack, clearing out the leaves and other litter that had accumulated since his departure and patching some holes. Tanjirou would have to come back later to maintain it, if not to visit his family’s graves. He couldn’t just abandon the Kamado residence in desrepair, it was an essential part of him, and his way to honour his family.

Crouching down, he whispered to Nezuko: “Please be silent, and don’t leave unless you’re in danger. I’m with slayers, they will want to kill you. I don’t want anything to happen to you. If they attack you, run away, and wait for me.”

A soft hum of agreement came from inside the basket.

Tanjirou rose from his crouch. Thankfully, it was not only overcast but also a new moon. Tanjirou could remove his scarf and gloves and people would be unlikely to notice due to the darkness. He placed these on the ground next to the basket.

He decided to keep his uniform and shoes, though. The rest of his clothes he would have time to wear once the monster was lured.

He waded into the water, and the other two watched.

Chapter Text

It wasn’t long before the demon noticed him. As they chased right behind him, he used some of his demonic strength to get to shore in a few seconds, then picked up his sword as he turned to the demon, who had exposed themselves to the air.

The other slayers approached, flanking the demon from both sides.

The demon laughed.

“Two more mizunoto slayers for me to devour. As for that demon…”

The demon looked up. The kanji for six was in their left eye. They looked to be female, and their skin was a light blue, with long dark blue hair running behind their head. Her irises were a very dark shade of aquamarine, to the point that they almost looked black.

“I will report him to Muzan-sama.”

The lake water started moving, quickly surrounding the demon. The water breather immediately started slashing, trying to create an opening, while the thunder breather hesitated.

“It uses water! Let’s leave it to the water breather!”

Tanjirou was thoroughly confused. As he rushed in to help Nakashima, Kaigaku looked at them in shock, still not helping the fight.

Sun Breathing, Seventh Form: Beneficent Radiance.

With the omnidirecional attack, he sent the water flying, and him and the water breather attacked the demon from both sides. She disappeared entirely, appearing some paces behind Nakashima.

“Haha! Stupid slayers. Always fall for this one.”

Tanjirou stepped to the side and slashed right behind his fellow slayer, protecting her from a jet of water the demon had used. She thanked him silently as they got back into their stances.

So far, it seemed as if the waning moon had two abilities: control of water and teleportation. There was probably more to the latter, because Tanjirou had neglected to observe it before he had moved to parry the water jet. The demon might have used the ground below themselves to transport herself. Or her body might have been made of water, and the lake was her domain, allowing for her to move at will.

In any case, to prevent teleportation, a fast Breathing style would be needed, for cutting a neck as fast as possible.

A fast style like Thunder Breathing. However, Kaigaku had started actively backing off from the fight.

As Tanjirou continued parrying the water, not making a move to attack yet, he called out:

“Kaigaku-san, I think thunder breathing can slash this demon’s neck!”

Kaigaku acted like he didn’t hear Tanjirou’s suggestion. He turned heel and ran.

The demon had started constructing walls of water between the slayers and herself, then attacking with jets of water from those walls. Tearing through the water was trivial; not getting wet, though, was nearly impossible. When water spray had first touched him, he had expected something terrible to happen, such as it burrowing into his flesh. However, he just got wet. That meant that this water could only be controlled if it was connected to the main mass.

This also meant that the main body should have been connected to this same main mass. Sure enough, there were several narrow streams of water connecting the demon to the lake. Tanjirou suspected that if one were fast enough, they could separate the main body from the water, nullifying the demon’s ability.

Of course, this was all assuming that the demon’s main body was what he thought it was.

Tanjirou decided to take action.

He stopped parrying, dodging back a bit as he readied a form.

Sun Breathing, Fourth Form: Burning Bones, Summer Sun.

Tanjirou’s slash cleared a path through the water.

Dashing through, he went for the demon’s neck. As he suspected, the demon made a move to defend it, delaying him a bit, but then… dissolved herself into the water.

This meant that the main body could move through the water.

However…

Sun Breathing, Eleventh Form: Fake Rainbow.

Tanjirou had faked the attack on the neck. His afterimage faded.

He slashed the small corridors connecting the demon to the lake. All the controlled water fell, revealing a bruised but not cut Nakashima. The transparent world revealed copious internal bleeding. This demon relied more on blunt-force attacks than cuts and slashes, it seemed…

“Keep the demon away from the water!” cried Tanjirou.

Sun Breathing, Twelfth Form: Flame Dance.

Tanjirou used the combo attack to catch the demon off-guard and pushed her back away from the water she needed to travel. Nakashima used a water breathing form that seemed to get faster and faster, not stopping.

The demon was taking hits now, losing a hand then an arm as she did not have a medium to move in anymore.

She liquified the other arm, and sent it as a jet towards the water breather. To allow her attack to continue unimpeded, Tanjirou parried it before it could get close. His wrist got sliced halfway by his teammate due to the unexpected parry, but it healed nearly instantly as the duo continued chasing the demon away from the lake, on the clear dirt near the water, into the forest. At this point, Kaigaku had completely disappeared from view. Tanjirou could not spare time to look for him.

Suddenly, the demon completely gave up on defending.

A slice to the neck revealed that the demon had escaped, leaving their clothing behind, floating on some water. The water fell to the ground as it was sliced.

Below where the demon had been was an inert puddle. It smelled faintly of demon, but the actual demon had already gone from the puddle by the time the slayers reached it. The soil around the puddle was wet, almost muddy. The waning moon might have escaped into the ground, and already been deep at this point.

Tanjirou noticed Nakashima’s rage spelled clearly on her face, and its scent overwhelmed his nose. It was mixed with a torrent of hatred.

“That demon… was the one to kill my family. I know it now. And it has the gall to run away? I will kill it.”

Her breathing started becoming more laboured, and the scent of rage intensified. And yet, Tanjirou could swear he heard cackling coming from the muddy ground they stood on.

He put a hand on the slayer’s shoulder, looking at her with bright red eyes filled with concern.

“Nakashima-san. The demon running away is not your fault. It’s not even really my fault. It’s the demon’s fault. As a demon slayer, one will always have to know to accept failure…”

She moved to push him away with a palm, but hesitated.

“What the hell do you know about failure? You’re so strong, the demon didn’t even nick you!”

Under Nakashima’s skin, blood pooled everywhere. She was almost falling to the ground with the sheer volume of blood she had dumped into other tissues. He had underestimated the extent of her injuries, even when he had looked at her with the transparent world before.

“Nakashima-san. I know about failure.”

She started crying a bit. Tanjirou could tell that her rage was directed more at herself than at anyone else. She gave off the bitter scent of self-hatred.

As if to make the situation worse, the demon emerged from the lake again.

“Cry about it. Pathetic. Loser. Someone like you can never decapitate me.” Tanjirou did not miss the slight waver in her voice.

He turned to look at the weakest moon.

“Demon! You’re the one who ran away. You’re a coward. You’re the one who can only fight on your own home turf!”

The demon had already gone.

Nakashima had doubled over from her injuries. With gentle hands, Tanjirou brought her head up to look at his face.

“Nakashima-san! You have to learn to move on from your self-loathing! Shou! Come here!”

Tanjjirou’s Kasugai crow flew down.

“Could you please report that this lake has a lower moon with good evasion abilities?”

“Sure.”

The crow flew straight back to headquarters. Tanjirou watched his bird for a bit, before turning to his other companion, who had by now stood back up on shaky legs and was looking at Tanjirou. He looked back.

First, Tanjirou waded back into the lake, to goad the demon back. The waning moon did not bite. She was completely gone.

They then walked back to Nezuko’s basket. Wearing his scarf and gloves, he shouldered the load.

“We should probably stand guard in the nearby town for the time being. We should assure them that even though the demon ran away, we can protect them. Hopefully the corps will send more slayers to cover the town, so that we can attack the demon and defend the town at the same time. Also, we can fetch a doctor…”

“Yeah.”

As for the third member of the group… Kaigaku had truly fled far. Tanjirou’s senses could not locate him, and people could die while the two remaining slayers chased after him. They decided to leave him be.

As they walked, Nakashima started asking some questions about Tanjirou.

“What did the monster mean when it mentioned ‘that demon’? Was that you or Kaigaku? Also, what’s in that bas-…” An open door appeared under Tanjirou.

It swallowed him whole. He was falling.

“ket…?”

Opening his eyes, Tanjirou shouted out from inside: “Protect the town!”

The door closed, disappearing.

Chapter Text

Tanjirou looked around him.

It was a completely illogical location he found himself in. Wooden buildings stood seemingly with no support, some sideways, some even coming down from the air. The only rule governing it seemed to be that everything sat at right angles to each other, which created a surprisingly orderly formation. It could almost be called a work of art.

Looking though the spaces between the buildings revealed yet more, stretching off into the distance until the air itself swallowed the light up.

Lanterns lit up each building and door with an orange light.

Rotating his head to look down, Tanjirou noticed seven demons below him. Some of them seemed to be bickering, while others sat among the ordered chaos. Tanjirou could not tell much more than that from this distance.

This space had to be created by a Blood Demon Art. There was just no other way a place like this could exist.

As he fell and got closer to the demons, he started catching some words through the rushing of air about his ears. “Akaza”, “waxing moon”, “five”…

Finally, Tanjirou landed on the platform, standing straight and looking around him warily.

Surrounding him on the platform were five demons. He sensed one more in a room closeby and the seventh on a staircase behind him. The closest one to him, who had rainbow eyes that read ‘waxing two’, opened his mouth to speak.

The sound of a biwa echoed through the halls. The platform teleported.

All the demons looked up to a higher platform. All that was visible from this angle was the head of a demon whose hair covered her face. This castle might have been this demon’s blood demon art.

She spoke.

“Welcome back to the Infinity Castle. Muzan-sama has declared that the demon with the hanafuda earrings should be captured. He will be returning in twenty-four hours. If you fail to capture him the punishment will be severe. Begin now.”

“We will not disappoint you, Muzan-sama!” the rainbow-eyed demon promised.

Every demon leaped on Tanjirou.

These were waxing moons. All of the waxing moons. Tanjirou probably did not stand a chance. Not with his current strength, at least.

Sun Breathing, Eleventh Form: Fake Rainbow.

Tanjirou appeared to fall to the floor, then disappeared, instead dropping onto one of the buildings jutting in from the sides.

Right behind him, Tanjirou felt a blade cleave through the air, and smelled something foul. He stuck his floor into the floor at an angle, pulling his upper body down to dodge the sword strike. He then swiped his sword back up with Setting Sun Transformation, blocking the small white crescent-like blades, probably this demon’s blood demon art. The demon locked eyes with him as the form’s backflip brought his head completely around.

The waxing moon had six eyes. The middle two read ‘waxing one’, signifying that he was the strongest demon after the progenitor himself, but his scent still had some vestiges of fear, just like the progenitor himself…

The waxing moon used a sword form to attack him, Tanjirou’s parry sending him in an arc through the air and straight into the ranks of other demons.

He knew that his best strategy would be to try to evade rather than fight, and then approach to threaten the demon on the raised platform. Tanjirou had already seen the biwa in her hands, and the biwa note seemed to hold significance here… It was the sound that was heard the moment the demons had teleported, after all. This meant that she would probably have the means to escape this place.

He dodged the waxing moons’ blows for the most part, gaining a scratch here and there as he dodged several attacks every second, passing and breaking through various rooms and hallways as he dodged backwards, slowly separating the demons such that he could fight them individually or in pairs.

Due to the sun’s absence, Tanjirou coninuted accumulating injuries which would not heal beyond their bleeding stopping. He would go down soon.

…

Two minutes or so later, Tanjirou’s basket lost one of its two straps. He noticed Nezuko stir.

“Nezuko!”

He parried some strikes from a demon who used obi, grunting as his feet slid on the floor against the other demon’s superior raw force.

“I’ll tell you when to come out!” he continued.

“Get the basket! There’s something in it!” shouted the sickle demon at the obi demon.

That backfired badly.

…

The second strap broke after ten more minutes. Tanjirou had gotten better for a few minutes as he got more warmed up, and some of his smaller injuries even healed, but this was counterbalanced by the sloppiness brought on by the basket weighing down one arm.

He was losing whole fingers now.

“Nezuko! Now!”

Nezuko leapt out of the basket, and having observed the events from the holes that were accumulating on it, she immediately jumped into action, kicking a demon with a large growth on his head away.

A horn had sprouted from the right side of her forehead, and green and red vines wrapped around her skin. This was her true demonic form.

“Nezuko! Try not to lose too much blood!”

Nezuko, who had been preparing to slit her wrist, hesitated.

The two continued being beaten back, step by step.

…

In Tanjirou’s opinion, the most annoying attacks came from a demon who could manifest large pots into existence, and teleport between them. The demon would always attack him from his blind spot, earning him lots of scratches, and a lost finger, between his numerous blood demon arts.

At this point, Tanjirou could barely use his left hand, with it only having two fingers left. Nezuko had started using her blood demon art, but only sparingly, usually to burn the floor to dodge attacks.

They were getting better.

But they were also being worn down and Tanjirou was getting injured.

Giving up all hope of attacking the enemy had gotten them half an hour of survival. Not a second more. And this was against one or two enemies at a time, who sometimes did not even use their blood demon arts at all.

Tanjirou was not strong enough. The waxing moons were just playing with their prey. They had had many openings so far, and all he could tell was that they were enjoying this in some sick way. Some of them were, at least.

Yet Tanjirou’s sword had not turned crimson. He was not fulfilling his potential either. He did not know if it was a question of mental state, tiredness, or something else… but he felt sluggish, and just could not force through his block.

Not yet, at least.

The six-eyed demon had ambushed them from the back while the siblings fought the demon with ice and fans. Waxing one had mostly been absent from the fights so far. Maybe it was because of that fear he sensed earlier.

It didn’t matter.

Nezuko was delimbed. Her arms and legs lay discarded on the floor, removed cleanly by one of waxing one’s sword forms.

The rest of the demons stopped, to watch Tanjirou’s reaction. After all, this was just a game to them. A spectacle.

Tanjirou caught her body, dropping his sword. Her mouth moved, and she started speaking for the first time since she became a demon. Both her voice and her scent were filled with determination.

“Consume… me.”

Huh?

“Absorb… me… onii-san.”

“Win… for… me.”

Tanjirou nearly hesitated as he willed his body to absorb his sister’s. He didn’t really know how this worked. He closed his eyes. The other demons still didn’t move.

When Tanjirou’s eyes opened again, the first thing he saw were his ten fingers. Ten.

All his injuries were closed.

He kicked up his sword, catching it and grabbing on tightly.

A voice spoke inside his head. A voice like Nezuko’s. Nezuko’s own voice, maybe? He had not heard it properly in so long…

Tanjirou, I know you can do this.

Giving himself a once-over using the Transparent World, he saw another heart and brain, in his right thigh and left shoulder respectively. He could guess that those were what was left of Nezuko.

There was no time to mourn.

Except that when he looked around him, the other demons were still frozen.

Not because they were letting him take his time, but because… time itself had crawled to a halt.

A hand laid on a hilt and two others on fans, as all three moved slower than an ant crawled.

Something in his head told him that he didn’t have long until time resumed.

His sword quickly turning bright crimson, Tanjirou bore a hole towards the biwa demon’s scent.

It was not difficult to find her, still on her platform, one hand on her pick and the other on her biwa.

He was not a second too early to rest his sword on her neck. Time almost immediately resumed.

“Let me leave.”

The biwa demon didn’t move. A banging sound from the surrounding hallways and rooms got louder and louder. The other moons would be here any second.

“Muzan-sama will torture me. You will kill me. I pick you.”

Her scent almost seemed content as he sliced her neck.

A one-eyed head fell to the floor. Tanjirou sheathed his blade.

Immediately, the carefully crafted Infinity Castle started falling to pieces. Tanjirou tried to move up as much as possible, whatever that meant in this place. The other demons had bigger concerns than capturing Tanjirou at that moment, while the Castle violently rumbled and seemed to shrink in size, ash dropping from melting walls and floors.

Soon enough, the whole construction had disappeared, and every demon within had been buried in a sea of dirt and rock.

Digging through the mass of earth with a combination of demonic strength, passive strength from Breathing, and Nezuko’s Blood Demon Art, Tanjirou finally managed to claw his way to the surface, immediately running as fast as his legs could take him (which, with his current condition, was very fast).

Behind him he left a huge mound of dirt in a forest, the other waxing moons probably getting out one by one.

He heard his sister’s voice again.

You did it! Now, get stronger, and continue fighting!

Even if just in his head, his sister was still alive.

And now that she was not at danger of death from Tanjirou’s missteps, he could finally approach the higher-ups of the Demon Slayer Corps with his newly-gained information. He knew it would be valuable.

Chapter Text

Tanjirou knew that his crow would probably have no idea where he was, so he sprinted towards and up a nearby mountain to situate himself, reaching the summit in about half an an hour.

He saw the sea closeby, and a bit further it curved into a bay.

From what he could tell from his few months of travel, he was at the west coast of Japan, but not much north or south of Tokyo. He could see a few familiar mountains from this summit, but not Mount Kumotori.

I love the view.

The vista was beautiful, and this was amplified by the sunrise peeking over the landscape. And Nezuko’s voice in his head…

He abandoned the summit immediately.

The sun both gave him strength and singed his skin as he jumped down entire cliff faces at a time, quickly reaching the forested base. He ran east, looking for wisteria.

…

Tanjirou smelled demons hiding in caves near him as he ran.

They all died nearly instantly by his blade, it taking less than a second between his detecting them and reducing the demon population by one. Absorbing Nezuko had helped him get much faster.

Eventually, he made it… somewhere.

Wisteria stretched on before him. He just had to step in. Easier said than done, since for some reason, the sun was not enough anymore to keep the wisteria’s pain at bay. Its very scent burned Tanjirou’s nose and lungs, and he soon started choking on blood. His eyes were irritated too, but to a lesser extent. Fusing with Nezuko had probably transferred her weakness to wisteria to him.

However, surrounding himself in Nezuko’s flame helped burn the offending flower before he could breathe it in. He had realised a while ago that his sister’s flame could target many things in broad categories, such as scents, demons, or metals. It could not target humans or animals, though.

He slowed his pace. Now, he just walked serenely among the wisteria. He was probably safe from the waxing moons at this point, and certainly from weaker demons.

Wow… so pretty! I wish you didn’t need my fire to walk here!

Wisteria was a beautiful flower when one could appreciate it rather than be repulsed by its mere scent. The fire distorted and discoloured the purple flowers, making them look red. He probably would not be able to see them again.

They look red? I see the flowers just fine.

Nezuko could read his thoughts.

“Wait, how?”

Haha… you can just talk in your head! This is our space, nobody can hear us this way.

Tanjirou narrated in his head: how do you… see fine?

I think I can see from the fire’s surface. It’s like… it’s a part of me. I think you can do the same.

Thank you, sister!

Tanjirou closed his eyes and the Transparent World, and saw a blur before his perception. Focusing on it revealed a full view of the wisteria around him, stretching all the way to his back and above his head. It was dizzying. Was this what Nezuko was subjected to, at all hours of the day? Could she even see at all when she wasn’t using the flame?

I can see just fine, silly! We share perception, but you control everthing on your own. I’m used to the ‘flame-vision’.

Tanjirou sighted a building ahead. He would probably have to stop using the flame.

He slowly turned it off. His lungs started burning again. However, the irritation of his eyes was manageable, and that was when they were open. Closing his eyes stifled the pain.

For his lungs, he could either hold his breath, which would become apparent to everyone pretty quickly, or burn the wisteria the moment it entered his body.

He set his lungs ablaze with Nezuko’s blood demon art, deciding to tolerate the burning in the rest of his airways for now, since he did not have fine enough control over the fire to cover those too.

You are a smart boy, you know! I don’t know what I’d be doing in your place!

Stuffing back the ‘it should have been Nezuko who survived’ back into the recesses of his mind, Tanjirou stepped out into the clearing near the house.

His ears picked up some sounds from within the house. His nose would have alerted him to any human presence much earlier, if it was not burning constantly.

He came face to face with a man in a half-and-half haori, the left half with green and yellow geometric patterns and the right half a solid red. He had striking blue eyes and messy black hair.

“What are you doing at my estate? You’re a lower ranked slayer, aren’t you?”

Tanjirou stopped and tilted his head a bit. The man had somehow sensed him from inside his home. He would probably be a very strong slayer, with those senses.

“I’m Kamado Tanjirou. Who are you?”

“I’m the water hashira. Now go away.”

“Hashira-san, I have important information.”

“I’ll repeat myself, get out.” The hashira’s expression and tone were completely flat, as they had been throughout the conversation, but his words were not.

“Could you show me someone who would accept it, then?”

“I dunno, go to Kochou-san or something. You look injured anyway. Don’t bother me.”

Oops. Tanjirou’s uniform was torn in many places, and had some blood stains. It would be reasonable to assume that.

“Could you please show me where that is?”

“Like that way.”

The water hashira pointed a finger in what looked to be a random direction.

“Thank-”

“Now scram.”

Tanjirou bowed, turned, and walked away. He heard a door slam behind him.

You should have roughed him up. He was acting annoying on purpose, maybe you could beat some sense into him.

Nezuko, I can’t just attack people.

He ran back out through the wisteria, and when he was far enough away, he turned off Nezuko’s flame and took a smell of fresh air. Tanjirou almost felt as if he was opening his eyes again. He had never felt so blind for so long before.

Keeping in mind the direction, Tanjirou sprinted, vanishing to the human eye.

…

It took all of five minutes to reach another forest of wisteria. It was not noon yet.

Entering with Nezuko’s fire as before, Tanjirou eventually made it to a much larger estate, which had many people relaxing in its large yards and gardens. Some of them had clear injuries, and tapping into the Transparent World revealed that many had cracked ribs, broken limbs, or internal bleeding. This was probably some sort of hospital.

For demon slayers only, by the looks of the wisteria surrounding it.

Stepping out of the forest, Tanjirou spotted a girl with two blue butterfly-shaped hair clips on either side of her long black hair. She called out to him.

“Hello Slayer-san! How may I help you?”

“Hello! I’m Kamado Tanjirou. Could I please speak with Kochou-san?”

“She’s busy at the moment, she will be ready in an hour or so. You can relax in the- are you sure you don’t need medical help?”

“I do not, thank you!”

“Feel free to tell me if you’re disturbed or in pain. I’m here for all slayers.”

“Thank you!”

Tanjirou walked to a tall tree surrounded by well-trimmed grass, and laid down to stare up at its branches and green leaves. It was still summer.

…

He had passed an hour ruminating on the events, and thinking of what exactly to tell this ‘Kochou’. He would have to pick his words carefully.

After he felt like an hour had passed, Tanjirou got up, and stood next to the entrance of the estate. Sure enough, the same girl as before emerged, bringing with her a young woman.

“Hello, Kamado-kun!” she exclaimed. “Come inside.”

She was smiling, but something about it made Tanjirou think that it did not belong on her face. He followed the woman inside.

“Ara ara, are you one of those slayers who gets injured and then avoids treatment? That would be bad, no?”

“I’m here to give some information, Kochou-san.”

She led them to a small room with a tatami floor, and invited him to sit.

“Now speak.”

“I have information on the waxing moons. I know all of their abilities and even some of their personalities. Should I relay these to you?”

“How did a lowly slayer like you acquire this information?”

Tell her you’re a demon.

“Hmm… I am a demon.” Tanjirou removed his scarf and gloves, then opened his eyes.

“Hmm? If so, since you’ve admitted and left yourself defenceless, I’ll let us be friends if you atone for your crimes! Does that sound right? How many have you killed, demon?”

She leaned threateningly over him, despite them being about the same height.

“Kochou-san… I have not killed anyone. The reason I am here is for giving information since I was nearly captured by Muzan.”

She paused for a second.

“Very well.”

You know that demons aren’t allowed by Muzan to say his name, right? They die a painful death if they do.

I didn’t know. She did know, right?

Lucky!

“Waxing six is two siblings. One of them wields a poisonous sickle, and the other can create and control obi like a snake. I heard another demon joke about the girl being a prostitute in Tokyo. Waxing five…”

…

“Two is a demon with rainbow eyes and light blonde hair. His attacks involve ice.”

Shinobu twitched a bit.

Even though his sense of smell was dulled to nearly nothing, Tanjirou noticed the scent of anger hanging around this woman like a veil. He stopped talking.

And yet her smile stayed on.

“Kochou-san, did you lose somebody to that demon?”

“No.”

Tanjirou was nearly certain she was lying, but decided to continue on to waxing one. It would do no good to provoke negative memories in someone else.

“Waxing one is a demon who wields a katana, and uses breathing forms. He might have been a demon slayer at some point. I saw him in action the least out of all of the demons. However, I can confirm that his blood demon art creates blades shaped like sickles, which fly unpredictably through the air.”

“Thank you!” She did not change her smile, but it had a small twitch, as if wavering. It would have been imperceptible if not for Tanjirou’s enhanced sight.

“Any information on Kibutsuji Muzan?”

“I did not see him… since I was turned. However, there was a location called the ‘Infinity Castle’ that he used. I think it allowed for him to hide away, since it was the product of a blood demon art and had no real-world presence. I killed the demon responsible for maintaining it.”

“Hmm… so this means that for some time Muzan and the waxing moons will be forced to be in the real world. So, when you saw him, what did Muzan look like?”

“Muzan… came to my house… and killed my family in front of my eyes. He was wearing a white western suit and white fedora. His blood demon art involved tentacles, I think.”

“The information is appreciated. As for you… I will send a letter to Oyakata-sama, but until he sends a response you must stay here. After all, you are the first sun-resistant demon, and possibly the only demon not under Muzan’s curse. Just wait in this room.”

She walked off.

Tanjirou laid down in the empty room, staring at a white ceiling.

Chapter Text

While waiting for Kochou to come back, Tanjirou decided to hold a conversation with his sister, something he had not truly done in a long time.

Nezuko, could you tell me what happened since you became a demon? I know that this will be painful. Sorry.

No problem, brother. When I woke up, I was furious at Muzan. That anger stayed with me even though I was a demon, and as I beelined my way to your unconscious body. I could tell you were losing blood. I could not resist the smell and the temptation of fresh blood at the time. Sorry.

No need to be sorry. I know I would not know too much about it, but demonic hunger is very strong.

Correct! I only had eyes for the blood. I think my resentment for Muzan and seeing your face as I shifted my position were what snapped me back to reality. Otherwise, I might have killed you. It really was a close thing. Who knows what I would be if that came to pass… Anyway. I saw the ropes with which he had tied you down. I got so mad at him, not only because he had killed our family and degraded us both, but also expected me to eat you, as if you were a meal on a platter. I shredded those ropes until I could not recognise their shapes anymore.

You know, he made a grand speech to me before I passed out, as if he was trying to make himself feel special to me. He told me that he would be my master, that I should never say his name, and that he had created me from his blood.

I fed you Muzan’s blood since you were dying. I wanted to save you, and had no other choice. And I was scared of you, when you were performing the Kagura. Some deep-seated thing in my mind told me to pull away. I think I only truly broke his curse when I stayed where I was, against my instincts.

I think I burned my own curse away. Maybe that is why Muzan is so scared of Sun Breathing… because it burns demons like the sun.

Probably…

After watching your kagura, I remember falling asleep in the house. My mind felt hazy, probably because I hadn’t nourished myself. I remembered nearly nothing. When I woke up while you fought against the spider demon, my last memory was of that night at the house.

In the time in which I was asleep, I relived my life.

Remembered our family whole before Father died. Remembered your absolute determination and how we had to pull you back from training to make sure you rested. Remembered the day when you were so frustrated at yourself for failing the kagura that new year that you worked for sixteen hours straight and collapsed.

I saw each of my siblings’ faces, remembered every intricate detail that was spoiled by Muzan. I relived the night of the tragedy several times in my dreams. I’m desensitized to it, at this point.

After I started waking up again, my mind was still foggy. I only really understood the world around me when I was dismembered, probably because my brain finally realised that we would die soon.

For all intents and purposes, I gained consciousness when I was already a part of you. Don’t worry, Brother, it’s not been sad. I like being here. It’s like basking in Father’s flames, but constantly, as if they surround you.

Nezuko, you’ve grown a lot since we last really spoke.

Glad to know it! I’ve had too much time to think.

Tanjirou would probably have to wait for many more hours. He did not want to antagonise the Demon Slayers, so he would stay put. He was missing the sunlight, though.

Come to think of it, he didn’t think he had managed to use his own blood demon art yet, even if he had used Nezuko’s so easily.

It’s because I was the one activating it! I read your thoughts. Thank me, Tanjirou!

… Thank you, Nezuko. I just want to ask, how does it feel to use the blood demon art?

I guess you just will it to work. I used mine when I had lost some blood, and was focusing on a use for it.

So if I cut my arm-

NO! Brother, you… nevermind, you have to do it, sorry.

Taking his gloves off, Tanjirou drew his claw against his arm, drawing some drops of blood. He did not have to focus hard to prevent the regeneration, since he was not in the sun.

He recalled the time he had been decapitated by the spider demons, but somehow had managed to keep his head connected to his body. Maybe he could solidify his blood?

Looking down at his arm, he saw the blood droplets freeze. He ordered them to become liquid again, and they complied.

Then, he tried something more complicated. He drew some more blood, and willed it to make a small clump. It complied and made a small ball on his skin. Maybe he had some form of blood manipulation?

Finally, he willed it to become a dagger. It nearly instantly complied again, the blood flowing into the shape of a blade. He flipped it into his hand, regenerating the scratches.

Hmm. This blood demon art seems more intricate than mine. Unfair! Why don’t I get something this cool? You can do so much with this, Brother!

I could use it for air mobility, by solidifying blood then pushing off. Or as a secondary attack. Can I use it when not bleeding? What about if it’s not touching my body?

…

Tanjirou answered most of his questions, and continued practicing the use of his technique.

It turned out that the only limit to his blood manipulation was how much blood he had, and he did have to be touching it to use it. He also learned that extracting blood from below his skin without a cut was difficult, but possible. He finally found out that disconnecting then reconnecting his blood to his body maintained his ability to manipulate it. This would mean he could store extra blood and use it. Maybe he could just sit in the sun and extract blood, then use it later?

Tanjirou was now focusing on external blood manipulation. He created threads, protruding from various areas in his body, and waved them around.

As he practiced using his blood manipulation, he focused on thinning the strands, moving them more accurately and quickly, and increasing their durability, testing the latter by using sword forms on them. He accidentally damaged the walls twice, but it would probably be okay. He would apologise, after at least trying to fix them. Any lost blood was easy to clean up, just by coating the floor in a thin layer of his blood and picking any excess back up.

He then tried infusing the threads with Nezuko’s blood demon art. The only change that made was that his blade turned red as it neared the strands, and that they would presumably inflict more damage, though Tanjirou was not in an environment to test that.

He was slowly tiring himself, though. Not being out in sunlight for so long had drained him of energy, and now the sun was setting. As he felt a bit lightheaded, he tried to push blood up to his brain. Surprisingly, it worked. He gained a brief respite from his tiredness.

Tanjirou then sat down and started trying to control his circulation more precisely. He already had some skill from using his Breathing, but he realised he could augment this base strength by several times by using the blood itself as a muscle.

Soon, however, Tanjirou was truly feeling tired. He laid down in a corner of the room, and closed his eyes. He trusted the people here. Even if he did not have his sense of smell to back that up, Tanjirou knew that he would be safe. This was a hospital.

Good night.

He drifted off to sleep for the first time in half a year.

------------------------

Shinobu had sent a crow to the Master about the existence of a sun-resistant demon who had broken free from the curse.

The Ubuyashiki mansion was far away. It would take time for her crow to return.

Meanwhile, she could think about the information provided by the demon.

It had personally witnessed waxing two. That did not help, though, considering it could be anywhere, roaming free, killing more people like Kanae, people with sisters like her, slayers who would help others…

That demon though… It had walked in the sun, broken the curse…

Shinobu somehow doubted that it could even be killed at all. She had let rationality take over, for once.

She had seen it stare straight through her gaze, as if it was looking behind her face, inside her body.

Despite its good manners, it was probably hiding something sinister within.

It was truth. Demons never changed.

…

Shinobu had continued studying in her laboratory when her crow flew in through the window, landing on her desk, which was yellow with lantern light against the inky black of the summer night sky.

She stared at the crescent moon outside, before turning back to the crow, who stood as silent as always.

Unfurling the letter from its leg, Shinobu read the letter.

Shinobu my child,

I would like to call a meeting of the hashira. I feel like the times are changing. We might make a breakthrough soon.

Bring the demon child with you. Make sure that they do not show their demonic traits. The meeting will begin as soon as everyone arrives.

Ubuyashiki.

As expected, he was much more tolerant than her in these matters. Though Shinobu knew somewhere deep in her heart that this demon could not be killed by conventional means, the other hashira did not, and would not be disturbed as much by the Master putting himself in this much risk.

Shinobu did not understand the man sometimes.

She went to the room she had left the demon in. She could not help but feel angry at this creature as if it had personally gone and killed her sister and tsugukos.

When she passed through the door, the demon seemed to be sleeping. Sure enough, it did not respond to her entrance, and continued laying down on the ground.

“Demon. Wake up.”

Its ears twitched at that, and it slowly pulled itself up, as if it needed to go so slowly. It still looked drowsy.

“You will go and meet with the hashira. Come with me.”

The demon agreed happily. It also started apologising.

“Sorry about the walls… I damaged them a bit. How could I repay you?”

Shinobu ignored the question. That seemed to shut it up.

She exited to the yard.

“Disguise yourself again. I will knock you out and take you to Headquarters.”

“Hmm… Okay!”

It pulled its scarf tighter around its mouth, and put on its gloves. Its eyes had not opened, even when it had woken up.

Embarassingly enough, Shinobu had to hit twice to knock the demon out. Nobody was left outside to witness it.

Chapter Text

Sanemi’s night had not started nicely. His day sleep was interrupted by his crow, who asked for his presence for a hashira meeting, outside of schedule.

Fuming a bit, Sanemi readied himself and left the wind mansion.

…

As far as he could tell, he was the first one there. So much for the rush. He still felt a bit of pride.

Soon after him, the other hashira started arriving. The Insect hashira had arrived last, carrying a boy on her back.

The boy… had every place a demonic feature could be covered. The eyes were closed, and the hands and mouth were obscured. A demon? … He (it?) was unconscious for now.

Shinobu’s small frame dropped the boy in front of the hashira, who had lined up in no particular order, in front of the engawa.

Sanemi immediately started speculating.

“Is this boy the reason we called this meeting? I can’t tell, but it might even be a demon. I should remove the gloves and check.”

Sanemi walked forward, uncaring of the concerned glances being shot at him, and approached the young boy.

He saw large tears in his uniform, but no cuts to go with them. The demon theory was getting stronger by the second.

Suddenly, the boy took a large breath and got to his feet. His eyes were still closed, but he looked straight at each hashira as though he could still see them.

“Hello hashira! I am Kamado Tanjirou. Nice to meet you!”

Sanemi had stopped in his tracks. The only response came from Kanroji. She was always too friendly for her own good.

“Oh, he’s so cute! Eyes closed like a baby, that birthmark…”

Sanemi took another look at the boy and saw the demon crest. At that point, there was not much confirming left to do.

He pulled out his sword, and aimed it at the demon.

“Hashira-san! No need for violence!”

Shinobu chimed in:

“Let us wait for the Master.”

Sanemi wanted precisely that not to happen. A demon, before the Master? Not on his watch.

“Boy. Are you a demon?”

“Yes,” he replied with surprisingly little hesitation.

Sanemi swung his sword to decapitate the demon. Only Kanroji moved to intervene, but she was too late. The sword sliced the demon’s head completely off, its still calm and… almost happy? expression remaining, unchanging. Kanroji fell back, letting out a gasp.

The demon’s head did not fall off, or turn to ash. Instead, it nearly instantly reconnected with its body, and the cut was invisible after a second.

This demon might have been unkillable by Nichirin.

Too confusing.

Amid the extremely tense atmosphere, Sanemi returned to the side of his coworkers, deciding to let more astute minds handle this.

The demon stood where it was, and seemed to suppress a grimace, muttering something like ‘Zuko, no.’ Who was it talking to?

Gyomei spoke: “Such a poor soul… It is possessed by a demon. We must put it out of its misery…”

None of the hashira made a move, though. Everything was at a standstill, save for the hashira’s thoughts.

Eventually, the Master walked through the door, and sat down. The demon, seeing everybody else kneel, knelt itself, as if it respected the master. Both of his eyes were glazed over, and his skin’s disease had spread even further down his face than the last time he had seen him.

“Oyakata-sama! I hope you are doing well!”

Rengoku, with his usual fiery spirit, greeted him.

“My children… it’s a fine night. I think the moon is a crescent… I come bearing some unexpected news, news that could change the tide of this war.”

“The demon which you see before you is immune to the sun.”

“Impossible!” Sanemi burst out, but he had already seen it withstand a nichirin blade. That was analagous to sunlight, in most cases.

Tomioka stayed quiet.

Gyomei was crying, counting his prayer beads.

Kanroji’s face had an expression of almost pleasant surprise.

Rengoku spoke too: “The demon has withstood the slash of a nichirin blade. But withstanding the sun is impossible!”

Tengen remarked: “I must admit that this demon is very flashy, acting like nothing happened after being beheaded. A demon of this flamboyance may be very useful as an ally!”

Muichiro stayed silent, looking up at the sky with empty eyes.

Shinobu also was silent, and had that smile on her face.

Iguro unsheathed his blade, but otherwise did not make a move.

The demon in question just nodded.

“My beloved hashira… This demon has broken free of Muzan’s curse, and has been friendly so far. In fact, he has also encountered and fought all six waxing moons.”

At that, the silence died.

Sanemi could not believe it. A demon of this potency, surviving against multiple waxing moons? Who knows how many humans it had eaten… It would be absolutely unforgivable to let it live.

“With all due respect, Master, this demon must have eaten thousands of people, to be able to survive against Muzan’s strongest servants, and escape them, if that is to be believed. We must find some way of killing it.” Sanemi maintained his stance.

The demon in question and the Master started talking at the same time.

“Wisteria works-”

“I ask you all to not harm this demon. He is a valuable ally, and has not killed or eaten any human.”

What​ ? The demon… had told them how to kill it? Though Sanemi very much doubted that it was telling the truth.

Rengoku: “We cannot spare a demon without concrete evidence it is working firmly for us.”

Sanemi put his blade to his arm. “I propose we test it against marechi.” He dragged the blade, releasing that blood that was so intoxicating to demons.

The demon tensed up a bit, but stayed in his original position, still kneeling.

Sanemi stabbed the demon. No reaction.

He slashed across the back of its torso.

At that, the demon turned around.

“Please stop that, you’re tearing my bro-… my haori! And tend to your wound! Idiot.”

The voice that came out was feminine. Huh?

But that did not stop the fact that this imbecile had called him an idiot.

How dare he?

The other hashira and the master watched as Sanemi slashed again at the demon’s throat. This time, the blade was caught with a strand of blood, and the demon opened its eyes.

Glowing pink, with slits in them.

The demon’s face had a new mark on it. One resembling… vines.

“My brother refuses to defend himself, so I will. He’s so damn reckless!”

All the hashira tensed, and a few swords were drawn. Even the normally stoic head of the Ubuyashikis seemed a bit spooked.

Soon, however, Sanemi lowered his sword, and the demon’s eyes shifted colour to a much brighter crimson, before closing again. It smiled to itself, and somehow seemed slightly flustered.

“Nezuko, please don’t do that again. Let them figure it out for themselves.”

Did this demon have more than one identity?

It kneeled again, its injuries nearly instantly disappearing. Did not eat any humans my ass.

The Master spoke again: “The demon cannot be killed by nichirin, yet he does not attack you, even with you being a marechi. Is this not proof enough that he is an ally?”

Sanemi still mistrusted it. “Shinobu, could you not try poisoning it with wisteria?” The ‘the demon suggested it itself’ went unsaid.

“I am against that, not because I do not want to kill the demon, but because it is a valuable asset. Think about it, Sanemi-kun… This demon can fight against upper moons with a nichirin blade. I will experiment on it to create a poison that could kill it if necessary, and it will travel with a hashira wielding that poison at all times. Does that sound right, Sanemi-kun?”

The demon was silent.

Sanemi grumbled a bit, but it was true that there could not be any other course of action. Everybody here was at the mercy of the demon, as long as some suitable poison did not exist.

The Ubuyashiki continued: “However, we cannot let the demon fall into Muzan’s clutches. If he does, then Muzan will truly be unstoppable. Though, considering he managed to escape his grasp once already, that should not be too much of a concern, especially with a hashira always travelling with him.”

The hashira did not show much reaction. They mostly seemed to accept that this monster would help them, though Sanemi was still stubborn.

“Since you have accepted this, the meeting is concluded. Shinobu, take the demon back to your estate.”

Shinobu departed first, taking the demon with her. Except that instead of going with her, the demon commited its first act of defiance since the meeting started.

“Oyakata-sama, could I ask something about your illness?”

The insubordination was not punished.

“Go ahead, child.”

“Is it caused by a demon?”

“Yes, but not by a blood demon art. It is a curse that every male in the Ubuyashiki bloodline has had for the centuries after producing Muzan.”

At that, the demon seemed to slump a bit, then thanked the Master for the audience and left.

Sanemi was just confused, as he left with the others. Their conversations with each other did not help him out at all.

A demon was now in the Demon Slayer Corps.

Chapter Text

Four months had gone by since the hashira meeting.

Tanjirou had started doing missions with the Flame hashira, but after showing his independence and not having any problems, he was sent off with a vial of extremely potent wisteria poison for suicide in case of capture. He was entirely ready to use it in that case.

He had been sent to Asakusa as his first mission since he was freed from the constant vigilance of the Corps. He actually missed Kyojuro’s presence a bit. He had started forging a friendship with the Rengoku after months of being together, and even coming with him to the fall hashira meeting, but he would have to start making himself more useful anyway.

The most remarkable encounter had been with a strong demon, probably almost at a level with the strongest spider demon, but it was not even a moon. Tanjirou felt like he should cover more ground, anyway, if the missions tended to be this easy.

He had now been handed a list of several average to difficult missions to complete and help with, since as a demon, he had the capacity to take no breaks during his work.

However, the difficulty of the mission was not the only thing Tanjirou had to worry about. For one, Asakusa was absolutely overwhelming.

It felt like day, even though it was night. Tanjirou could barely pick up the few demonic scents among the seas of people, some of which even had small cuts and incisions that gave off the tantalising scent of blood. Since absorbing Nezuko, his compulsion to eat flesh had increased, especially in the night, and he was almost tempted to pull someone aside and… eat them. Even this was only a fraction of the hunger Nezuko had resisted, though, so he had absolutely no excuse to lose control. He was not weak. He was a big brother.

As he walked the streets, mostly sticking to the edges and alleyways, he caught a scent that he had wished he had never become acquainted with.

Kibutsuji Muzan.

The other demon was walking with a human family​? along the street. Tanjirou ran off silently nearly immediately, since a confrontation in such a population center would lead to many deaths.

That man’s scent had radiated intense anger, and even held the residue of other people’s (demons’?) scents on him, mainly demarcating fear. Tanjirou could tell that there were six distinct residues. He could guess whose those were. But to be heartless like that, to punish your own subordinates, that was another level of low. As far as Tanjirou had witnessed in the Infinity Castle, the waxing moons were completely loyal to him, and the only reason Tanjirou had escaped was because of a completely unpredictable circumstance. It was not their fault. He almost pitied them…

Lost in thought, Tanjirou bumped into a woman who was walking the same alleyway as he was in.

He stopped and turned to apologise, only to see the hallmarks of a demon on her.

She was with a boy who looked to be of a young age, but who was also a demon.

The woman mouthed a nearly silent word: “Yoriichi?”

The boy opened his mouth to speak, but closed it as Tanjirou continued with his apology and unsheathed his blade. However, he hesitated, because the scent of the two held only traces of blood, not the full impact of rotten flesh like any other demon who had eaten recently.

“Wait! I don’t harm humans! I am Tamayo, a doctor, and this is my assistant, Yushiro. We wish to defeat Kibutsuji Muzan too.”

They’re free from the curse too!

Tanjirou sheathed his blade again, and approached the duo. He had smelled only sincerity, and a very faint scent of disinfectant.

Smiling, he opened his eyes, and looked at the two.

The boy was obviously startled. “You’re a demon too? You smell like… fire, not like a demon! How?”

“You two don’t smell like demons, or really… much of anything else, either. My name is Kamado Tanjirou. I’m resistant to the sun, that’s probably why I don’t smell like a demon.”

Both demons seemed shocked. Tamayo interjected: “Let’s talk this through at my place. We won’t be noticed there.”

“Good idea, I saw Kibutsuji Muzan walking the streets.”

The woman’s posture relaxed somewhat, even if her words would have indicated the opposite: “He’s here?”

------------------------

As Tanjirou followed Tamayo and Yushiro through the streets, Tamayo couldn’t help but compare this boy to Yoriichi. Both smelled pungently of fire, had the same birthmark (though Tanjirou’s could have been a demon crest), same earrings, same blade colour… Even their hair and eyes matched fairly closely. And yet, there were many notable differences too, such as Tanjirou’s glowing smile, his younger physical age, and, of course, his being a demon.

Tamayo slowed her pace as she smelled demons up ahead. Rounding the corner, she saw two of them, wide smiles on their faces, one nearly prancing while the other walked with his head held high. The female held a temari, and the male had his eyes closed and eyes in the centers of his hands.

They barely had time to react as their heads rolled off their heads to the slashes of a bright red blade. They immediately started turning to ash.

“Those smelled foul.”

Yori-… Tanjirou walked back to them with his blade turning back to a pitch black, but he kept it unsheathed, turning back to look at the two demons.

“You- You’re the demon Master talked about!” the male cried.

Suddenly, red arrows burst forth from his disintegrating hands. Tanjirou deflected them and stabbed the hands with his sword.

Surprisingly enough, the boy kneeled and brought his hands together in prayer before he returned to Tamayo.

…

When they eventually made it to Tamayo’s house, the atmosphere was dead quiet. Tamayo was the first to break the silence.

“You remind me of someone.”

“Yoriichi, right? I feel like I have heard that name before.”

“You two are so alike… He was the inventor of Breathing, from the Sengoku period, and the strongest demon slayer so far, even if you might surpass him…”

Tamayo trailed off, but her posture and expression were as relaxed as always.

“We should introduce ourselves! I am Tamayo, and I am a doctor. I help people to atone for my past sins. Yushiro is the only demon I have managed to turn within the last two hundred years of my research.”

“Two hundred years? How old are you?”

“Don’t ask a woman for her age, swine!” Yushiro snapped. Thankfully, he did not move.

“Please excuse my rudeness!” Tanjirou immediately rectified.

“It’s not a problem. I am over three hundred years old. After Muzan got weakened significantly from a battle with Yoriichi, I managed to break free from him by medical means, and stifle my hunger to require only tiny quantities of blood. Yushiro here can survive on even less. I am wholly dedicated to ending Muzan once and for all. I must make up for the dozens of people I killed and ate with my own hands and teeth.”

“I know you’re not lying. Thank you. Muzan is the only person on this planet that I truly hate. I would be honoured if I could help you take him down. Also, I feed off of sunlight, so I do not eat.”

“Hmm… There is not very much that is useful against Muzan, save for sunlight, since he is too powerful to be affected by poison for long, and does not die when decapitated. But your condition is so outlandish, that you might help our research significantly. Could you explain a bit how you are resistant to the sun?”

Tanjirou briefly explained what happened to his family that night, how he danced Sun Breathing’s forms despite his imminent death, how he survived. He apparently was only thirteen years old, much too young to be doing such work, though his line of work held little mercy for age.

When he finally finished, Tamayo asked: “What happened to your sister?”

Tanjirou’s voice shifted to a more feminine tone. “I’m still here. I sacrificed myself to free us from Muzan.”

Tamayo was incredibly surprised, to say the least.

Tanjirou’s voice switched back. “After I became a demon slayer, I fell into Muzan’s hideout, called the Infinity Castle. To escape it, I killed the demon whose blood demon art had constructed it. The situation was dire. Muzan himself was not there, but his subordinates were. My sister had to sacrifice herself to save us.”

“I’m sorry… Your case is extraordinary in every way. You are not only the first demon to conquer the sun, but also the only demon I know of that has two different consciousnesses.”

“Nezuko’s brain and heart are still intact, in my body. She can read my thoughts and use both of our blood demon arts, but I can only use my own, and can only hear her when she ‘speaks’ to me. Her blood demon art can burn anything that is not a human or an animal, selectively. My own is blood manipulation.”

“Very unique. Though I must ask, could I take a sample of your blood to analyse it? As I said, it could be very useful.”

“I would gladly. Thank you for letting me help you.”

Tanjirou bowed slightly from his sitting position. Tamayo asked Yushiro to retrieve a syringe, while the new boy stayed put, looking around him a bit.

“Ah, could I ask you something more, for the cure?”

“Go ahead!”

“I will need a lot of Muzan’s own cells for this, so could you retrieve some of the demon moons’ blood?”

“Sure! Do you have a syringe or something, or…”

“I have these.”

Tamayo handed Tanjirou some of the small automatically sucking syringes she had made for an experiment some years back. He accepted them.

“My cat, Chachamaru-”

The cat in question interrupted by jumping into Tamayo’s lap.

“-can turn invisible, from Yushiro’s blood demon art. Chachamaru will appear whenever you have collected blood, and return it to me.”

Yushiro returned with a large syringe, and they extracted Tanjirou’s blood. He then got up, thanked them for the hospitality and the opportunity, and left.

…

Tamayo was still studying the blood, days later.

It appeared that two different types of demon cells were living in harmony. This was already unheard of, but what was even more interesting was the symbiotic relationship the two seemed to have. When exposed to bright light, Tanjirou’s sun-resistant cells covered Nezuko’s more normal demon cells. However, otherwise, they seemed to completely ignore each other.

After leaving the samples in the sun over the day, the cells had multiplied significantly. Tamayo was glad she would be able to keep a sample of these cells this easily.

Aside from this, Tamayo finally had a working theory on why Tanjirou had become sun-resistant. It seemed to take metaphors too seriously, on first glance, but it would make sense if true: the sun flowed through the sun breather’s veins as he danced, forcing all of his demonic cells to adapt and evolve to benefit from it, to not be scorched and die. He had heard something about it from both Muzan and Yoriichi.

Muzan had told her once that Yoriichi was such a nuisance because he was made of sun. How his attacks hurt so much more because they infused the sun itself into demons’ blood.

Yoriichi had told her in one of their very few conversations about how he could not teach his own method to others, since their blood did not carry the sun like his did.

She had already resumed work on her weapon against Muzan. But Tanjirou was potentially as much a weapon as Yoriichi already. One could hope.

…

A few weeks of study passed quickly, and Tamayo received her first blood sample. What was odd was that there were two samples, and the syringes’ exteriors were also covered in blood.

Extracting the samples with care, she placed them under a microscope. Sure enough, there was an incredibly high concentration of Muzan’s blood. Maybe even waxing moon levels…?

Finally, something concrete to work with. Now progress would be made.

Chapter Text

Tanjirou knocked off tasks from his lists like an automaton. By a week since his meeting with Tamayo, he had already killed nine demons, and rescued some slayers from difficult situations.

However, he was starting to see a glaring issue with the Corps.

There were way too many slayers who somehow could not do Breathing forms properly. When he asked them what style they did, everybody responded, but when asked to demonstrate, a quarter could not do every form, and a third could not channel their battle spirits enough to create the effect of the breathing style they used. At least Total Concentration Breathing was something everybody knew; it was about the baseline for being able to change the colour of a sword. But being at the baseline was too dangerous.

And Tanjirou realised that he was almost contributing to the problem, by killing demons that other slayers could not. The others were simply not getting enough experience to kill demons reliably.

So Tanjirou made it a habit to bring some bandages with him, and wrap up the wounds of fellow slayers before training with each one or each group for a few hours before disappearing to his next mission. It was not much, but Tanjirou could see vast improvements in many of the slayers that he tutored for such a short amount of time. It warmed his heart.

Tanjirou had sent a crow to Master about Mount Natagumo, and the moon demon that resided there. He had responded that slayers were not going to be sent there for a bit, for a higher rank to handle them. Tanjirou had not paid much attention to the ranks, but last time he checked, he was a Kinoto, so he expected the mountain to turn up on his next list of missions. It did not.

No matter. Tanjirou found being in cities very unpleasant, but he did not mind it too much, because they were always also so magnificent looking back. He wanted to go back to Tokyo, because he did not get much chance to explore it before. He could even visit Tamayo again. So he went there exactly two weeks after he had left.

The scent of demons lingered in the air slightly, but Tanjirou could only detect one. However, their presence did not change, however much he moved around. He decided to ignore it for the time being, instead choosing to gape in wonder at the amazing technology that this place had. Tanjirou had not even dreamed of some of these inventions!

Tanijrou, you’re overreacting. …

There seemed to be some sort of carriage without horses, for example. And some large hunks of metal that moved on rails, carrying people around the city. He had always been a country boy, so this had impressed him probably too much for his own good.

Tanjirou, stop gawking, come on, kill demons!

Anyway, Tanjirou eventually could not ignore the constant scent of demon. It was the same scent all the time. He could not pinpoint its location, given the number of people, so he decided to walk through all the districts of the city.

Eventually, he made it to the Entertainment District. Speaking of which, he had heard the waxing moons joke about the Entertainment District…

The place smelled… terrible.

There was the mark of abuse… blood. He smelled way too much of it for his liking, disgusting him to the point that his demonic instincts did not come into play at all. It was mixed together with a large dose of liquids Tanjirou did not want to think about, and a more potent demonic scent. The demon was in this area. And not only that… but Tanjirou felt like he had smelled this scent before. Except that now, it was… different. He did not know how to explain.

And it was also everywhere. The demon had left their mark on the area deeply. But it seemed to concentrate on one particular house.

Kyogoku house.

Hold on. Let me handle this. Trust me…

Nezuko’s words were cryptic, but Tanjirou felt like he understood what she meant.

Will you infiltrate that house?

Yes, brother… don’t worry, I can lie.

I’m not that comfortable, but if it helps save lives, I am all for it.

Good.

Tanjirou walked into a dark alleyway, and Nezuko took over. She could change her appearance more freely, so she hid her marks and made herself look more like a girl. She also changed her hair and eye colour, so that she would not be recognised.

Conveniently, she could also retract her claws and fangs and fix her eyes’ slits and colour, giving her a much more human appearance, so that she would not need the gloves, scarf, or to close her eyes. If only she was still human… if only they were. But being a demon helped them protect people. Somehow Tanjirou was almost grateful that he had become a demon, even if… his family…

Brother, it’s okay to feel like this. Seriously, stop beating yourself up about how you feel. You are who you are. …

All that was left was Nezuko’s scent. Since Tanjirou recognised this demon, they probably recognised Tanjirou too, so something would have to be done to mask that too.

Tanjirou, I will go buy some perfume, and deposit your belongings somewhere safe. I’ll also get some new clothes. Don’t worry, I understand your concerns.

Thank you.

Nezuko being in control of his body felt… strange. He trusted his sister, though.

Soon, they found themselves employed at Kyogoku house.

Now the time came to pinpoint the demon and fight them.

------------------------

Being Warabihime was boring. Being an Oiran for so long meant that she was no longer interested in it. But her disguise paid well in blood. Her brother appreciated it too. All in all, it was a stable lifestyle.

And she could satiate her still-sizzling anger against the people of this district, even if she did not remember why she had it. Good.

A new servant had recently been employed. A young girl with brown hair reaching her lower back, and brown eyes that seemed hopeful for something. Unremarkable. She would fit right in.

…

Daki had killed a servant. She had been rude to her, so she had ripped off her head with her obi. She ate the rest with her obi.

She called another servant to the room, for her to clean the mess. It was a child of age seven.

She left to change her clothes.

When she came back, the poor excuse of a servant was whimpering. There was nearly no work done.

“Hmm, child? Do your work!”

The child continued to whimper. Daki held her by her ear, and started twisting.

“I said get to work.”

Suddenly, someone burst through the door. The… new servant. Her name had been… unimportant.

“Stop that!”

She held Daki’s arm with more strength than it looked like she had. That would not matter, though. This girl was angering her.

She threw the servant through the wall. The little girl who was not doing her work had esacped her grip, but was at least looking like she was trying. Daki almost felt pitiful.

Why would she feel like that?

Once the dust had settled, the girl she had thrown had disappeared completely, leaving behing no blood, no shred of cloth, nothing.

Suspicious.

------------------------

Nezuko was already concerned about the demon.

It was waxing six alright, but she had also drawn suspicion to herself. She would have left some blood behind, but its usefulness for Muzan’s conquering the sun was too much to risk him getting possession of it.

And now came the largest predicament: How could it be possible to fight this demon, if it was in the midst of such a large population center, without killing people? Sure, she could wait for the demon to make an outing, and follow her, but who knows how long that would take? More people would die in that time period. It was a losing game.

That did not mean she couldn’t continue investigating the house. Maybe she could save some people from the demon, since people were going missing around these parts. Even though they tended to be described as escapes…

Though this would be a lot more convenient if Tanjirou was here. Now they were implicitly connected, but with blood manipulation, maybe…

In an empty room, she extracted half the blood from her body, and formed it into the shape of her brother. Into it she placed her brother’s brain and heart, painfully extracting them from her body.

When she disconnected the form of her brother, she expected it to fall apart, but instead, his body remained roughly intact, albeit completely red.

Tanjirou, can you make yourself look normal? I know it’s a lot to ask, but…

I can try.

Somehow the mental connection was preserved too? This was perfect.

Tanjirou’s form started being covered in skin, before he stopped for a bit. He was thinking about clothes. Made sense.

Just as Nezuko reached for some clothes, she felt her brother feel satisfied. Looking back, she saw that he had managed to create clothes from his blood. Even she could not do that yet. She was happy for her brother.

Eventually, he managed to look like how he did previously. However, he had not stopped focusing. Soon, his form changed a bit more, hiding his mark and changing some more prominent features, until he looked like some random boy one would find on the street.

I can investigate a bit more like this, thank you! I smell lots of blood, and I am sure you do too. I will save anybody I find them in danger.

He started walking towards the window.

Brother, you also need the perfume!

------------------------

After applying the perfume, Tanjirou immediately started looking for the traces of blood. It smelled like injured people in this area too. Exactly what was happening?

He had been walking in an alleyway when he saw the first tunnel. It presented as a small but deep crevice in the wall, which twisted to go straight down.

It smelled of fear and… injured people.

But it was too small to go inside, and see what he could do. Except that Tanjirou, in his current form, was entirely made of blood. Could he change his shape freely now?

The answer was yes, yes he could. He could not change his brain and heart, though, so those would have to be handled with care.

Dissolving his human appearance, he became a large blob of free-floating blood.

He changed his form to become more long and thin, like a snake, and pushed himself through the hole. It was not tight at all; he easily snaked along its length in a matter of thirty seconds or so, deeper and deeper into the ground.

On the other side, he turned back into his human form, and looked around.

A sash snaked across a cavernous room. It was completely dark, so he could not tell much of the surroundings, even with his demonic sight.

What he could tell, though, was that the injured people were in this room, and that the sash was alive.

Chapter Text

Tanjirou looked around the forms of the sashes. He was seriously struggling to see.

Coming a bit closer, he let his eyes glow a bit. The sash became more visible. It had the same pattern as the obi demon’s sash, and the same smell too. He had seen these in the Infinity Castle as well.

Looking around a bit more, he saw what looked like a drawing of a person on the sash. Tanjirou could smell a person right there, though, and the Transparent World showed bones and muscles where they should be, though they were shoved into a very narrow form factor.

He began piecing together a theory of how this obi demon worked.

She abducted people into this area using tunnels, since the sash was small enough to fit through them. Then she would store them here to eat them later, though why she would wait to eat them he did not know. Still it would make sense.

Now, he had to save these people.

He had not been noticed yet. The sash was unmoving.

Nezuko. I found where the obi demon keeps her prey.

I can see through your eyes. Yes, you can save them, Brother.

Thank you.

Forming some of his blood into a sword, he went into a stance. It also started faintly glowing with Nezuko’s pink flame. Her blessing to his sword.

Sun Breathing, Ninth Form: Sun Halo Dragon Head Dance!

He shredded all the obi with a single attack, making sure not to touch the areas which had humans in them, using a combination of scent and the Transparent World.

He saw people emerge from the obi, as it fell to the ground. Suddenly, it all started flying straight up. Tanjirou turned his body back into a mass of blood, grabbing onto the retreating sashes with his blood manipulation.

Nezuko, I can’t destroy these sashes, could you please help out?

Anything for you!

The sashes he was holding onto flamed, then disappeared. Not one managed to escape. However, Tanjirou had used about a fifth of the blood in his body. Not good.

He reformed into his human form, which took much less time than before, and turned his attention to the victims.

Wait, sorry sister, could you give me some light? There’s quite a lot of people here, and I might have to treat them…

Tanjirou’s hand burst into flame.

About twenty people lay on the floor in front of him, and more behind, from what he could tell from the flame vision. Most were unconscious, but two of them were up. They were both women… but one of them seemed to be a child.

He recognised both their scents. How could that be possible?

Looking closer, he saw that one of them was Nakashima Natsuko from the lake mission. What was his luck, to run into her again like this? And he had used his blood demon art pretty obviously…

“It’s a demon! Kill it!”

The other woman called out.

However, neither of them had any nichirin on them at all. Nakashima seemed to work up some courage, and ran towards him, her fists in front of her.

“Nakashima-san, it’s me.”

She froze.

“What? You… fell into the floor, and became a demon?”

Tanjirou smiled sadly. “Not really. I was a demon all along.”

“You lied to me!”

At that, Tanjirou felt a pang of guilt. He really had hidden something important from everyone, for quite some time. He was guilty of working over his negative reaction and learning to lie. Changing something so deep about him felt wrong.

Brother, you never really lie! This was necessary! Come on, have some faith in yourself.

Tanjirou had looked to the other woman. She was approaching too, and held some stones in her hands. He finally remembered where he had smelled her scent before. It had been on the tall hashira who had talked about ‘flashiness’… he had not heard the hashira’s name, but she was surely affiliated with him.

“Wait, both of you are with the Corps, aren’t you?”

The other woman looked at him with narrowed eyes.

“What do you mean?”

“The Demon Slayer Corps. I am a part of it too. I was investigating the waxing moon here. You… know that hashira with the white hair and eye tattoo, don’t you?”

“You mean Tengen-sama? Yes.”

“Thank you for trusting me! But I must ask, how did you end up here?”

It turned out that the woman’s name was Hinatsuru, and she was Uzui (the Sound hashira)’s wife. She had been investigating the same house as him, and had been abducted by the demon after rousing her suspicion, then taken here.

Nakashima had not seen the lake demon again. Tanjirou had suspected that the demon had followed him and pinpointed his location, else the biwa demon’s blood demon art would have needed to be stronger than he knew it was – to be able to open a door beneath him wherever he was. In any case, she had moved on and gotten some mundane missions after that, but actually worried about him not coming back. For all she knew, the lake demon was still alive.

“Do you two want to fight the demon?”

“Yes, but we don’t have any weapons, I lost my sword…” replied the water breather.

“Hold on, I will try something.”

Tanjirou did something he had not tried before. He tried to create life. After all, his body was made of blood, and it was not disintegrating. He formed the shape of a tiny heart in his hand, made it beat, and covered it in more blood, making the shape of a sharp katana. He solidified it, and asked Nezuko to make it lightly burn.

With the heart in it, the blade retained its form, even when he was not touching it. It would take a few hours to run out of blood to burn, at this rate. He also decided to remove the sun-resistant cells from the blade, which was a surprisingly easy process. He tested this by using sun breathing with it. It got torn to shreds.

As the other two looked on in confusion, Tanjirou made two more blades, handing one to Nakashima, and the other to Hinatsuru. The latter refused, asking for kunai instead, as those were her weapons of choice. He changed the blade into multiple kunai, but he needed a way for the disposable weapons to not get captured. He resolved to add a small brain that detected when it had hit its target, and combust with Nezuko’s blood demon art accordingly. It worked surprisingly well for a first try, and after testing it out, he changed all of Hinatsuru’s weapons.

“These blades are made of my blood, but they can still kill demons. The blades will burn in the sun, though.”

The water breather tried a few forms, and, seeing the blade work well, she kept it. Her only complaint was that it was too light. She refused Tanjirou’s offer to fix it.

Meanwhile, Hinatsuru had taken to her weapons very well, thanking him for his help.

“Great! Let’s go!” Tanjirou said as he grabbed the other two and broke out through the ceiling.

They found themselves in the midst of a street. It was high night.

Nezuko, have you found any way to confront the demon without risk?

No. She seems to confine herself to her house a lot. We would be lucky if there were no casualties. –Oh… oh no. She’s onto me. Come, fast!

Sorry!

“Nezuko’s engaged the demon. Should I take you there?”

“No, point us in a direction and go!”

Tanjirou pointed to the direction of Kyogoku house, and vanished. He appeared behind a wall, watching a confrontation between her sister and waxing six.

He was only about a second too early, as right then, an obi snaked out from behind her and pierced her stomach.

She was quick to react, and jumped back towards Tanjirou.

ABSORB ME NOW!

ON IT!

Tanjirou was quickly sucked back inside his siblings’ body. Nezuko continued dodging attacks, as they destroyed more and more of the surrounding rooms. Now she was at a much faster pace, since she was no longer missing half her blood. She still opted to keep her disguise.

Nezuko, should I take over?

Go ahead.

The process took about a second, but in that small space of time, their body was impaled by two more sashes.

As Tanjirou recovered, he jumped straight up through the ceiling, breaking the roof tiles and landing again, a new blade clasped in his hands. He kept up his disguise, since it would not really hurt.

Waxing six followed him.

Taking a stance, Tanjirou ended the initial battle quickly.

Sun Breathing, First Form: Dance!

The demon’s head fell off, but did not disintegrate. As expected from waxing six. Her brother would have to be beheaded at the same time. Tanjirou had found that out the hard way. She had been the only demon he had managed to behead back at the Infinity Castle.

He whipped back as waxing six cried for her brother. He ran towards her body, but the brother had gotten out already. Such a simple attack could not kill him. After all, he was the reason why they were considered waxing moons.

He used Fake Rainbow to maneuver himself behind his enemy, then tried at an attack towards the demon’s neck. He repelled it fairly easily, using his two sickles.

The sister demon’s head was still off, but still not disintegrating. The brother put her head back on her head, as Tanjioru charged again. This time, however, he did not hit the male demon. Instead, he circled him as fast as possible, and released some of his blood, forming it into tiny shards. These he released at the demon. Nezuko made them explode on impact, such that the demon would be impacted. The attack worked fairly well, and goaded the demon into releasing his own blood demon art.

Tanjirou leapt back as he saw the flying sickles made of blood approach him. Instead of parrying, though, he let some of his own blood touch them, and then grabbed them. He could feel the poison inside them, but quickly broke it down as he absorbed it into his body.

He felt a boost of energy, and used Dance again. It was blocked by the obi demon this time, though he cut through the obi fairly easily. Then, he swiped up.

Sun Breathing, Fifth Form: Setting Sun Transformation!

This time, the sickle demon’s head fell off.

By now, Tanjirou had decided to let his disguise drop.

He swung at the obi demon, but was unable to decapitate her fast enough due to her turning her neck into a flexible obi. He retreated once more… and the other demons started running away, the sickle demon putting his head back on.

Tanjirou followed them.

But it was just a ruse. Sashes burst through the ground, as the brother demon unleashed his blood demon art once more. Tanjirou actually struggled slightly not to get hit by the flying sickles, and the forest of sashes that surrounded him was not convenient in the slightest.

However, he managed to push through, only to see a very angry waxing six nearly on top of him.

He parried six times in the one-second onslaught of blows, then witnessed a new blood demon art.

Cones of red seemed to erupt from the demon’s arms. Tanjirou jumped back, but was scratched slightly. He had not seen this art before, possibly due to how destructive it was. Even though the fight was still on top of a roof, many surrounding buildings were damaged badly, and many people still walking on the streets were gravely injured. Tanjirou had already failed to save many people.

But instead of getting mad, Tanjirou calmed himself completely. He entered his zone.

And the first thing he sensed was a thread leading straight to the sickle demon’s neck.

Chapter Text

Tanjirou let the thread guide his blade to its destination.

Sun Breathing, Second Form: Clear Blue Sky.

The sickle demon’s head fell off again.

Except this time, Tanjirou picked it up using his own blood demon art, surrounding it.

Nezuko! Now!

The large ball of blood collapsed inward, glowing pink intensely as it crushed the head within. It tried to bite the inside of the blood wall, but it was futile due to Tanjirou constantly shifting it.

Soon, the head was no more. However, the obi demon was still standing, and she was not backing down.

------------------------

The boy with the hanafuda earrings.

Right there, in front of her, without said earrings.

Her brother, without his head, behind him.

Daki was furious.

“Brother!”

That seemed to give this slayer a half-second of pause.

A third eye sprouted from Daki’s forehead. Gyutaro’s eye.

I’m here.

She felt her power grow exponentially. However, this slayer would not be possible to capture without the help of her brother. She would be powerless.

As her opponent struck fiercely, she dodged slightly slower. Parrying the blows dealt by a red sword was just impossible, so the only option was to dodge where possible and sacrifice limbs otherwise. Counterattack as a concept did not exist anymore.

She felt her brother coming back. Sure enough, across several roofs torn by relentless assault, stood her brother, with his head fully intact.

They were not holding back. They could win.

Daki used her Eight-Layered Obi Slash to give her brother an opening. Her obi made a dicing motion towards the slayer as a distraction, while Gyutaro snuck up from behind.

The slayer spun a full circle where he stood. Gyutaro’s head fell off again. And then she saw… the night sky.

Her head landed next to that of her brother. They looked at each other, as they started fading to ash.

The slayer climbed down, and looked at them both. Daki hated him at that moment, though something in her mind was wavering.

Another presence appeared, as Daki’s killer sank down to his knees.

It was the slayer’s sister. After the events of the Infinity Castle, she was still alive. She felt jealousy rise in her chest.

Her brother shouted out: “We were brother and sister! You understand! Why did you make us suffer?”

Memories started returning to Um- Da-ki?

A samurai asked for her services. He had given her a hair tie. She held it in her hand.

Gyutaro had told her that she had to defend herself, and not take things for granted, ever.

The samurai had that look in his eye.

Ume stabbed it.

“How dare you take my brother from me!” screamed Ume.

She was strapped to a log and staked into a pile of wood, which was then set on fire. She became numb to the agony of the roaring flames after less than a minute.

Next thing she remembered seeing was rainbow eyes with kanji on them.

She had her brother beside her. He looked… as he always did, just with fangs, claws…

They had been inseperable, through the terrors of life and the better times. They took out their revenge, felt powerdul. Daki had believed they would be together forever.

But Ume’s head laid on the floor, crying.

Yet still, they were together in death.

As she opened her mouth to speak again, she heard words muttered under the hanafuda earring boy’s voice.

“May you two be reborn in a better life.”

She hoped they would go to hell together, and be reborn together. Even if her and Gyutaro would have to endure every pain again, she hoped they could be together again.

Her eyes turned to ash, and darkness took over.

------------------------

Nezuko watched Tanjirou stand up and collect the two demons’ blood. Chachamaru was due to appear soon, if what Tamayo said was to be believed.

Though in an instant he froze.

Nezuko. Run.

It was a command.

From Tanjirou’s vision she saw blood tendrils splaying out over the corpses of the pair of demons.

Set them on fire!

Nezuko complied.

Her ears gave out, and her eyes saw nothing but the afterimage of a bright flash. Tanjirou’s vision was not much better.

As the ringing stopped, she had to reform her eardrums. Before her was Tanjirou, laid on the floor, his clothes absolutely shredded and blood leaking out of his unhealing wounds.

But he was alive. Just not moving.

What was not okay was the deep hole where the two demons had been, and the damage that had been done to Tanjirou. Nezuko could sense that he was unconscious. She reabsorbed herself back into him, and felt him gasp for air, his consciousness coming back.

Nezuko… are you alright? Is everyone alright?

Aside from hearing problems, nobody died from the explosion. Thank you, brother.

I still let people die…

It was not your fault.

Tanjirou stood up as he saw three people approaching him. Uzui, Hinatsuru, and Nakashima were here.

“Tanjirou! Long time, no see! I saw your fight, it was very flashy! But your flamboyance is ruined completely by your praying for demons! What was that about?”

Tanjirou was in a bad way. He had managed to generate new clothes for himself, as a kimono and haori, but… she could sense the hunger coming from him. It was getting stronger… and stronger.

This had not happened before.

This should never have happened.

He bared his teeth, and sank them into his arm. Nezuko felt him draw a lot of blood, but it was going nowhere but back inside himself.

He collapsed back onto the floor, writhing in a pool of his own blood. Nezuko tried to force a takeover, but her brother’s turbulent state of mind would not allow it.

She tried to coax him, telling him to calm down, that the sun would rise soon…

None of it got to him. Soon, he was back up, looking at the Sound Hashira with absolute hunger, fangs bared and arms tensed. The man he was facing almost looked scared. The hashira was getting ready to unsheath his blade as tentacles of blood burst out of Tanjirou’s hands, snaking around the surrounding buildings.

THINK, NEZUKO, THINK!

A tune came to her head.

Knock knock, little bunny on the mountain, why are your eyes so red? …

…

…

Tanjirou stopped.

I’m sorry.

He created a blade, and with a smooth motion, brought it to his neck. It was merely figurative, though. He could not die to sun blades, after all.

I don’t deserve to live… but you do not deserve to die. Take my body, sister. Make it yours.

Nezuko took back control. Right after, Tanjirou’s sense of self dimmed to nearly nothing. It was like he was trying to smother himself.

She looked at Uzui, retracting the blood that had gotten so close to innocent people. Their blood pooled back into their body. Her body…?

She changed to her own form. It was nearly exactly like she had looked while she was a human, but the tips of her hair were orange and her skin was covered in the red-and-green vine pattern all over.

Tanjirou’s flame mark had not entirely disappeared, instead presenting itself in isolated spots at the corners of her face.

Uzui spoke again.

“Who are you?”

“Kamado Nezuko. Tanjirou’s sister. He’s ashamed of himself for letting his hunger control him. We share a body, but he has given it up to me.”

“I was going to tell him that Oyakata-sama was willing to make him a hashira… It was a flamboyant proposition, and made sense given the flashiness of this battle, but… if he is not here, then I should leave. The kakushi should be coming soon. Come with me if you want to.”

After giving the blood samples to Chachamaru, Nezuko chose to follow the hashira.

------------------------

Makio, Suma, Hinatsuru.

He sent his wives to Yoshiwara to infiltrate the houses and investigate demonic disappearances.

Hinatsuru had stopped sending back letters one day. Uzui Tengen told the other two to leave, and went to investigate himself.

He arrived to the sounds of a battle and Hinatsuru running straight towards it with a random demon slayer.

Hinatsuru introduced the slayer and described Tanjirou as they ran together. He had seen the boy before, of course, but to think that he was fighting a powerful demon already…

As he made it to the scene, two demon heads rolled onto the floor. One with green hair like seaweed and black marks on its face, and the other with a flower mark and white hair fading to green at the tips. A slayer… Tanjirou knelt in front of them.

Suddenly, an incredibly loud explosion sounded, nearly bursting the sound hashira’s eardrums.

Tanjirou had been knocked unconscious, but a small figure next to him… disappeared? and he got back up.

When the slayer got back up, his previously solemn face turned into the vacant and hungry gaze of a newborn demon. Red threads snaked around the large crater that now separated the two parties.

They stopped.

Tanjirou created? his blade and brought it to his neck. He would surely not do something as lame as killing himself, would he?

Oh right, this demon could not be killed by decapitation.

The slayer’s appearance suddenly changed to that of a girl. Her eyes changed colour from red to pink.

…

Tengen was bringing the demon with him back to headquarters, accompanied also by the other slayer and his wife.

The demon girl had taken a short detour to get her brother’s uniform and blade. However, she had no use for them, not being a slayer using breathing. Not anymore, at least.

On the way, they encountered a demon with a blood demon art. Just as Tengen was moving to unsheath his blade, the demon girl already had a stranglehold on the demon, and her hand closed, decapitating the demon with a flash of pink flames. Somehow, the demon started turning to ash, despite there being no nichirin involved. Interesting…

Maybe this demon could still be a slayer.

…

They eventually made it. Tengen had left his wife and the other slayer in his estate. The blades seemingly made of blood were suspicious, but the kunai her wife had were surprisingly flashy, exploding in a flash of pink on impact, like a firework. Tanjirou might have made those. Such a powerful slayer, incapacitated of his own will…

…

The master had told him that Nezuko could, in fact, stay a slayer, and her rank could stay the same, according to Tengen’s assessment of her strength. She would also have to carry more vials of the wisteria poison, to kill herself in case of capture. But Tengen was still unsure if Nezuko would be able to defend herself against a waxing moon long enough to use the poison. He hoped she was. Hoped.

Chapter Text

Nezuko was depressed, to say the least.

Her brother was as good as dead, and though she had stayed a slayer, she still felt hollow inside, like something more was missing of her, as if her brother’s shutting himself had taken a chunk out of Nezuko’s own personality too.

The key differences in her uniform and demeanor were that she kept her eyes firmly open, and that she wore a different haori over the very same uniform. She had also taken off her hanafuda earrings and stopped wearing her brother’s sword and belt, leaving them all behind at the sound hashira’s mansion.

Her first mission was to go back to Mount Natagumo, with some other slayers who knew the ins and outs of the mountain. The very same ones that Tanjirou had worked with back when they were separate.

She met up with them at the base of the mountain.

“Hey… Hello again.”

“Huh? Again?”

The boy in the teal haori, who seemed to be in charge of this group, was confused.

“Momoto, what is this demon talking about? Let us kill it.”

“Wait, hold on.”

Nezuko continued: “Momoto… My name is Kamado Nezuko. My brother fought against the spider demons with you a few months ago.”

“You are the girl who fought with him, correct? He mentioned a sister. So, what happened to him?”

“He could not contain his hunger-”

“No. You mean he ate someone? That was a terrible mistake… a monster, unleashed upon this world, unkillable-”

“No, no, you see, we fused into a single body. He almost hurt someone, so I took over. He’s hiding now.”

“What?”

“Anyway, let us finish what we started.”

The group set off up the mountain. Nezuko had inherited her brother’s amazing sense of smell in this body, and managed to locate every demon precisely by the time they made it to any sign of the demons’ influence.

A slayer lay on the floor. By his scent, he was dead. Though suddenly, he jerked up, reminding Nezuko of the marionette she had seen in one of the villager’s homes. Sure enough, the slayer’s limbs were bound with incredibly thin spider threads, detected only by Nezuko’s enhanced senses.

Nezuko burned the demonic influence off of the slayer, and he fell to the ground, completely limp.

“Lead the way, Nezuko,” Momoto suggested.

She found two more slayers. One of them was alive, but the other was long dead. Burning the threads off the two, Nezuko approached the slayer who was alive, pushed him on his back, and looked into his eyes.

“Can you move?”

He left a seemingly catatonic state brought on by who knows how many hours or days of losing his bodily autonomy.

“Y-yes. I’ll… make it down.”

He got up, then collapsed.

“I can help you!” the member of Nezuko’s group with the ponytail called.

“Me too!” added another slayer.

The two slayers headed back down the mountain with the casualty, leaving four slayers still on the mission. This might not have been enough anymore.

They advanced towards the first concentration of demonic scent. It was a weak demon, probably the one controlling the threads, and by extension, the slayers, who had been on the mountain. Soon, Nezuko saw the headless body holding two blades, as she had before. This time, she burned the threads which gave it any semblance of being alive, and slashed it a few times with a blood blade before it started turning to ashes.

Finally, she made it to a clearing. The puppetmaster was sitting there, on top of a rock. Nezuko lifted her blade, and brought it down upon her neck. She made no move to resist. At the last possible moment, Nezuko decided to stop.

“Momoto… do you have a painless sword form?”

He quickly decapitated the demon with a slow strike perfectly along the edge of the blade, providing a clean (and hopefully painless) cut. Nezuko could smell gratitude from the demon.

“There is… a waning moon… on this mountain,” were her last words.

Momoto asked her, “why did you stop?”

“The demon surrendered. I felt it was the right choice to give her a painless death.”

“How are you even a demon slayer? I thought that you being a demon would not hinder your ability to kill, but it evidently has.”

“I did that because you were there. If you were not, I would not have hesitated. But I would have apologised.”

“… sure.”

The team moved on to the next demon.

…

With generous assistance from Nezuko, all the demons on the mountain were killed, with minimal injury on their part. However, just as the slayers were going to head down, one more appeared.

This one was much stronger. Probably the moon demon the puppetmaster demon had mentioned.

The demon was heading straight for the group.

“Stand back. The last spider demon is here. You know the one.”

How could they not? They had almost died to him. Back then, Nezuko had been the one to save them, and this time, it would be no different. No slayer here was above a Tsuchinoe in rank or skill, so Nezuko was the only one with a decent chance of defeating this demon.

The strongest spider demon showed himself.

“So you are the one who killed my family… Tell me then, what happened to your brother?”

“…”

“Very well. You were the weaker of the two anyway. And your brother cannot fulfill his role. He cannot protect you. He cannot save you.”

“…” Nezuko was getting worked up.

“And you brought the pesky slayers back. Weak as always.”

“At least they are stronger than before!”

At that, Nezuko attacked the other demon. From the element of surprise, she managed to sever his arm, but it was quickly regenerating.

As the spider demon moved to counterattack, he also sent some threads towards the slayers. Nezuko moved in close and burned all the connections the threads had to his hands. She then quickly manifested her own threads of red, and used them to cage the waning moon.

He tried to use some attacks, then infused them with his own blood. He was able to create a hole large enough to escape through, and dodged back a few paces. The cage closed with a pink light, and Nezuko continued on her pursuit.

She manifested a katana, and attacked in a pincer movement with her tubes from behind and her sword from ahead. The waning moon dodged to the side, but Nezuko had predicted this, lengthening her blade and finishing her swing on the other side of the demon’s head.

He started turning to ash, and Nezuko retracted her sword.

Though Nezuko should have predicted what would happen next.

She suddenly got ambushed by a pink-haired waxing moon she had become way too well acquainted with back when she had been in the Infinity Castle.

Waxing three.

Without Tanjirou, she would lose this fight. She knew it fully. As she reached for the vials of wisteria stored around her waist with her blood tendrils, which was a very short journey, they all got punched and shattered. Somehow, the demon even managed to hit her extra stores on her chest, arms, and ankles with attacks too fast for her eye to see. The liquid spurted out of the broken vials, and Nezuko even managed to absorb some of it, but most of the poison seeped into the ground, not allowing for Nezuko to so much as get a lethal dose.

Of course she was too weak. Too arrogant to realise that maybe, her brother had been so much stronger than her. Now she had no choice but to attempt to fight back against this immovable object, since nearly all the wisteria was gone.

“Run, slayers! Save yourselves!”

Waxing three quickly cut in. “Why are you bothering defending weaklings like them? You are a demon. Muzan-sama wants you captured anyway. I am taking you in.”

In the blink of an eye, the demon had knocked her out.

------------------------

Akaza would please the Lord so much with this!

He had finally captured the demon that had eluded Muzan for months. He would have to wait for Master’s approval, though, to be about to savor his victory.

…

The demon was brought to Master. He looked her over, then approved. He then walked over to where Akaza kneeled, and thrust his index finger through Akaza’s skull. In a procedure he was very much used to already, the Lord’s blood coursed through his own, increasing his own power even further. This was much more blood than he had ever received at a time!

But this time, like no other… he felt uneasy. Like there was something nagging at the back of his mind, something begging to break free. All he heard from it was the word “Hakuji”. He knew no such person. Or did he…?

Ha-Akaza watched as Master took his quarry and absorbed it. It was no more.

------------------------

Muzan called all the waning moons to his new home in the Tsuzumi Mansion. It was like a lesser version of the Infinity Castle, with a finite number of rooms, but it would serve for as long as it took him to find something better. The disgraced demon running it had his ranking removed, and now was unmarked, just like Nakime had been.

He had called the waning moons to be present right before dawn.

The five remaining arrived on time, just like dogs.

He started the meeting by appearing before them in a room with a door leading straight outside.

As the sun rose, Muzan was perfectly calm. The moons still waited patiently. Rays of sunlight touched the ground behind Muzan himself, but he did not flinch.

He had known since waning six told him that the demon with the hanafuda earrings was sun-resistant. Absorbing that demon would finally make him immortal. It was the last piece in the puzzle. Sure, the incompetence of his waxing moons had delayed his plans by a couple of months. But what was a couple of months in Eternity? The puzzle was now complete.

He would dispose of the waning moons tonight.

As his cohort watched, he stepped straight out into the sunlight. Brief flashes of fear ran through all of the moons, but he was obviously unharmed. He looked back at them.

“I am not interested in weak demons anymore.”

And in a second, he was on them. He reabsorbed all of his own blood back into himself, and threw the powerless bodies of his waning moons into the sun, watching them burn with the slight twitch of a smile on his lips.

Not one of them had the time to beg for mercy amidst their stifled screeches.

Chapter Text

Kagaya Ubuyashiki had an absolutely terrible gut feeling as the mission for Mount Natagumo was sent out once more. He had long known how to identify his gut feelings with his foresight.

What was to happen was the worst possible circumstance.

With this intensity of feeling, the Demon King might has well have gained a resistance to sunlight and found the Ubuyashiki mansion.

If that had happened, then the only thing Kagaya could truly do would be to pick a god to pray to.

And he knew that the first explanation he made for his gut feeling tended to be the correct one.

He had just asked Shinobu to create as much potent wisteria poison as possible. A situation like this had been completely unaccounted for. Nezuko’s presence in the equation had thrown off the balance of affairs significantly anyway… she would probably be captured by Muzan. It was a grave blunder to let her continue being a demon slayer. It would offer Muzan easy access to a sun-resistant demon. From that point onward…

…

Kagaya had rigged his mansion with enough explosives to replace it with a crater of the same size. In the explosives he had placed as much wisteria and bits of nichirin steel as he had.

As the finishing touches were being put on the system by his wife, Kagaya sat on the porch to his house, basked in the waning sunlight of the evening.

He was not yet completely blind, but would be soon. That was how he noticed Muzan Kibutsuji, who presented as a white smudge on his vision.

The man walked serenely between wisteria trees and sunbeams. The worst possible circumstance had come to pass.

“You finally came to me, right to me, Kibutsuji Muzan. The demon my family… the demon slayers… have been chasing for a thousand years… I’m sure you are mad at me, and my family, and are one who would not share their resistance to sun. That is why… I thought you would be the one to come and kill me yourself.”

“I’m disappointed, Ubuyashiki. I’ve lived a thousand years without aging, and you, through dozens of generations, have been reduced to this. Repulsive. You smell half dead already.”

“I should be dead. The doctors have been telling me, year after year, that my living to see the next one is not guaranteed. Unlikely. Impossible, even… But I am still alive and persisting, just as most of my ancestors were. To kill you, Muzan.”

Kagaya looked at Muzan with eyes devoid of focus and clear sight, watching.

“Your family’s dream will die in this day. I will kill you, Ubuyashiki.”

“You and I are of the same blood, Muzan. Did you know that?”

…

“The first demon came from your bloodline. So you must dedicate your soul to defeating him, so that your family may persist. That is what the priest said, as our family dwindled in number, every child dying before they even neared adulthood. But nobody, not even now, has lived beyond thirty.”

“And now you’re reduced to ramblings. It’s disgusting. Did your terminal sickness reach your brain already? And it does not matter to me. Are the gods punishing me for my existence? I have not seen or witnessed even one.”

But Yoriichi came close.

“So that’s what you think… Muzan. What is your dream? Now that you have lived for over a thousand years, and gained immunity to the sun, what do you dream of?”

Silence.

“How about I make a guess about the past, Muzan. I understand your soul. You have dreamed for all those thousand years of eternity. Of being indestructible. And you have achieved that. Now, what is left? What do you wish for now?”

Kagaya knew that he still yearned for eternity. But what was eternity to him anyway?

“Let me tell you something about eternity, Muzan. Eternity is human thoughts and emotions. You stand before me, having lost your humanity, in search of eternity. In doing so, you have rid yourself of the thing that makes it special. Kibutsuji Muzan, are you happy?”

“Nonsense. Of course I am happy.”

Both knew that that was a lie.

“The demon slayers have lasted a thousand years as well, Muzan. The thought of never forgiving those who have committed sins senselessly, the hatred and desire for revenge against demons, the determination of the human spirit to fight… are as eternal as humanity itself. You have never once been forgiven, in your centuries of existence. Because there has never been any remorse in any action you have taken. You are dead already… If you kill me, it will change nothing. If you died, the only trace left of your existence would be the demons you leave behind. They would all forget of you the moment you relinquished your hold, and their memories would not be passed on once they died.”

“But I cannot die, Ubuyashiki. Your speculations are nothing, if they are completely impossible. I have already transcended death. Zip it.”

“I have said what I wanted to… however, I must say one last thing. My death will be less than inconsequential. It will ignite the spirits of all those left alive, make them work harder than they ever have before to kill you, Muzan. You may think of yourself as beyond death. Humanity will find a way. They always have.”

“Are you done talking already?”

“Yes, but I did not expect that you would listen to me… Thank you, Muzan.”

The Ubuyashiki was at peace with himself. He would die to take this demon down. However unlikely it was that Kibutsuji would actually be harmed by his sacrifice, he had committed to the cause, and there was nothing left to do. Amane would be ready to set off the fuse now. It was a matter of seconds. The last seconds of his life.

Suddenly, three or four smudges shot out of Muzan’s body at various angles. They rounded back and ripped into his flesh, carving large holes into the progenitor demon’s body, as evident by the red filling Kagaya’s vision. The whole amalgamation of flesh then burst into bright pink flames. Nezuko’s flames…?

And as soon as it had begun, it was over. A new figure had taken the place of Muzan.

“Hello, Master.”

It was Tanjirou.

------------------------

From the moment Tanjirou and Nezuko had been absorbed by Muzan, they had been fighting an uphill battle.

They tried to resist being destroyed. Initially, Tanjirou’s soul was still asleep, but eventually he woke up too.

Tanjirou. You know where we are, don’t you?

Yes.

Good.

The two resisted being consumed with all their might.

It was like trying to hold the tide at bay. Both siblings knew that it was impossible. That they were probably experiencing their last moments.

As a last-ditch effort, the two decided to fuse.

This time seriously.

The two hearts and brains turned into one.

They were still losing.

Finally, Tanji-Nezuko? found a way to survive. It was the only way, and was the only way not to lose everything.

They fused with a pair of Muzan’s hearts and brains. They knew this would accelerate the process of Muzan’s gaining sun resistance. But it was only a matter of time otherwise, and the siblings would not be conscious to do something about it. Not that they could right now.

As the process completed, and they stopped needing to fight for survival, they felt absolutely exhausted, and neared sleeping. The pair laid dormant inside Muzan for a few hours.

However, they were still awake, however barely. They could not escape experiencing the things Muzan did, now that he had gained this new power. They saw through his eyes, felt his contentment, …

He killed his own subordinates. The people - the demons who had placed their complete trust and loyalty in their Lord. The same Lord who would kill them the moment they ceased to be useful, and would take pleasure in doing so.

The siblings could do nothing but sit in silence as the waxing moons finally found the Ubuyashiki mansion.

The only thing that finally managed to drag them out of their powerlessness was the scent of explosives.

Ubuyashiki was planning to kill himself to get Muzan. Muzan would not die to that, maybe not even get injured. The Demon Slayer Corps would lose its leader. The Hashira would all come, and be slaughtered.

They realised that they had been neglecting that fact. In fact, they had been neglecting everything due to how tired they were, because they were letting their guard down.

The demon king would kill so many.

How could they forget the value of those lives?

This was not a question of their willingness to protect others. It was a necessity to do so. And they knew that they could.

They finally got a grip, generating four arms to rip through the thousand-year-old flesh of Muzan. They ripped and tore, generating mouths to eat Muzan from the inside out, killing off all the other hearts and brains in his body, reducing him to a pile of flesh on the floor as they recreated their own body, then burning his remains. They stood on firm legs amidst the flaming blood.

Tanjirou and Nezuko were reborn into the world, fused together as one.

The pair’s bodies had been turned into one which shared the features of both. Their face had four eyes, two red slitted eyes above two pink ones. Their skin had vines and flames circling it, the former slithering across their pale skin and the latter dancing like real flames. They had four arms, two representing Nezuko and the other two Tanjirou.

And they had no name other than the one they shared. Kamado.

And so that was what they would call themselves.

Kamado was born.

Chapter Text

Night was falling upon the estate. The sun just barely peeked above the horizon, and soon would disappear completely.

Kamado continued, their voice not quite masculine or feminine, but a blend of both Tanjirou’s and Nezuko’s, just like the rest of his features. “Master, I am happy to see that you are alive. Call me Kamado.”

“… Kamado. Thank you.”

Kamado bowed at Kagaya, who was still sitting on the floor. He nodded back.

“I will protect you from the demons.”

A soft and understanding “I know.” was the Corps leader’s response.

Kamado turned around. They caught the smell of a powerful demon. Waxing five. They set their skin to a light simmer of pink fire, allowing them to see all around them easily. A panorama of wisteria greeted them, and the demon in question stood right behind them, unperturbed by the poisonous flower.

Generating a red blade flaming bright pink for the upper hands and two shorter daggers for the lower hands with their own blood, they leveled it at the demon, who was still hidden behind some trees.

One Dance, and the pot demon, whose main advantage was his speed, lost his head.

Then came waxing two and four.

Kamado locked onto four first. The demon had pre-emptively split into five different weaker demons. He ignored all of the unimportant ones as they recombined to form a stronger form, instead heading for the main body, guided by the Transparent World. The fear demon’s head fell with Clear Blue Sky.

They immediately turned onto waxing two, who had swiped with his fans, and contined executing the forms of Sun Breathing in order.

Raging Sun to block the fans .

Burning Bones, Summer Sun to redirect them .

Setting Sun Transformation to the neck stopped by waxing one’s blade.

No problem. Kamado could take on the two strongest demons remaining at the same time. They saw the other hashira trickle in around them, observing the battle that was too fast-paced for even a trained eye to see.

Solar Heat Haze to distance themselves.

Beneficent Radiance executed on both demons at the same time.

Sunflower Thrust to waxing one’s heart.

The demons were struggling to parry. Kamado knew that. The last form slipped through and hit, but Kamado retreated immediately, since waxing one was ready to counterattack. Destruction of the heart could slow even the strongest demons, though.

Sun Halo Dragon Head Dance to both of their heads.

Waxing one redirected the blow, making it cut off his arm instead.

Waxing two… ran away, after unleashing a blood demon art to block his escape.

Kamado could live with it. He still was fighting, after all, and could not feasibly chase after the escapee and kill waxing one at the same time. Waxing two was truly escaping, ignoring the hashira as he sprinted far away.

Fire Wheel to waxing one’s head. Parried.

Fake Rainbow to dodge the counterattack.

Flame Dance .

Waxing one’s eyes widened in shock as the second blow in the combination attack sliced his sword in two, followed through, and decapitated him. A single cycle of the Thirteenth Form had killed three of the five waxing moons remaining.

“Yoriichi… is that you?”

Memories started coming back to Tanjirou. Memories of the last weapon.

-

Yoriichi’s older twin had snuck him food again from the dinner table. He had already been beaten for the fifth time because of it. Yoriichi could tell through the Transparent World that his brother’s chest was badly bruised and he had some untreated internal bleeding.

After eating and talking together, after Michi had to leave, Yoriichi clutched at the flute he carried in his pocket.

He thought about his own words from a few months ago.

“I think of this flute you gave me as if it were you, Brother.”

Him and Michi were siblings. Even if he did not show it, making others think that he was blind, deaf, and emotionless, Yoriichi loved him.

…

Yoriichi had been cast out of the Corps for his failure to kill Muzan and his acceptance of Tamayo. He still killed demons independently, but no longer could he spend time with his comrades in this war.

…

They were all dead. The mark killed them all at 25. They dropped like flies. They were all dead.

Except for Yoriichi.

And Michi was gone.

…

He saw Michi again.

But his brother was long dead. Yoriichi could not accept that.

He failed to kill the demon who bore his brother’s face. He died standing.

-

And now the demon carrying his face was dying, releasing Michikatsu for one last time into the real world. Kamado finally recognised him.

“Michikatsu. This is tragic.”

“Yoriichi… I was jealous.”

“You know that I was the one more jealous of you, all that time ago. I never chose to be a weapon, not in this life, not the last. The circumstances made me into one.”

“And… you still… loved me?”

“Yes.”

Kamado said it with the utmost sincerity. Yoriichi had never looked down on Michikatsu, however much the latter felt like it was the case. If anything, he had looked up to his older twin for his whole life. He never thought of him as anything other than an older brother. It was the reason why he could not kill him all those centuries ago.

Kamado had nothing left to mourn other than their old brother’s death in the Sengoku period. His shadow laid on the floor, crumbling to ash after a brief moment of regeneration at the neck.

No more demons were left in the area. Waxing two and three were hiding.

Destroying their blades, the sun breather walked back to the hashira.

They bowed quickly. “I am Kamado. Nice to meet you again.”

Looking at the bystanders once again, they saw shadows of the people they had known in their past life. Tomioka with the old water hashira’s blue eyes, the Rengoku clan with their fiery hair, the Ubuyashiki head with his sickness…

Soon, Kamado had to turn back. Another presence was approaching.

Jumping deep into the woods of wisteria surrounding the Ubuyashiki mansion, he saw waxing three, walking in the direction of the battle. Kamado recognised the demon, and moved to decapitate him.

The demon in question was failing to block and deflect the blows sent his way, and even without the use of forms, Kamado could tell that the waxing moon would die soon.

Because he was holding back.

Kamado, wanting to finish things, brought their blade down upon their opponent’s neck.

When their blade had just barely touched the neck of waxing three, they picked up the scent of remorse and sadness, mingled with overwhelming fear. Out of curiosity, they hesitated. The other demon did not counterattack.

“Waxing three. Why is it that you don’t fight?” Kamado initiated the conversation.

“I… was Hakuji. I remember. I am… sorry. Keizo and Koyuki would not have wanted this. My father would hate me. Kill me already.”

“Hakuji… do you want to redeem yourself in life? Help humanity? I don’t want to kill those who feel regret.”

“I don’t deserve to live. After all I’ve done, all I’ve thought and all the people I’ve mindlessly killed… I don’t deserve retribution anywhere other than hell.”

“What do you mean you don’t deserve retribution outside of hell? Can you trust youself or not? You said it yourself. You were mindless, remembered nothing. That was not you.”

“I was willingly turned.”

Kamado could tell that that was not the full truth. He stated his suspicion.

“You were manipulated, were you not?”

------------------------

Hakuji remembered painfully.

He had committed so many sins as a human already. He was the reason his father died.

He remembered the last time he had tried for a new start in his life. Found a family to love and to take care of.

He had been struck down. A backhanded poisoning, and everyone he held dear had died, in a single night.

He had thought that maybe, just maybe, he did not deserve to live anymore. Having given up on life and seeking revenge, he used Keizo’s martial arts, his Soryu style, to kill everyone in the rival dojo whose members had poisoned his family.

When Muzan approached him, his acceptance was not one born out of genuine desire, but because he had nothing left to lose.

And thus, he had become an antithesis of himself. Akaza was one who insulted the weak and praised the strong. One who simply did not understand the concept of protecting those who could not protect themselves.

Maybe it was deserved. After all, he had failed to protect his very own family that day.

Or, he had failed to die with them. The poison was meant to kill him too. If he had died with his family, so many others would still be alive now.

Except that the poison had killed him. His memories died. He became someone else.

But after his late master had given him so much blood, his control on Hakuji’s mind had slipped. Fragments had started coming back to him. Bit by bit, he remembered his past life. Of course Muzan had not noticed. He was too obsessed with his new power.

Hakuji stayed back on the general summons to the Ubuyahiki estate. All he wished for was to die, to stop harming others. But his body still wanted to live. He was two then, but his demonic side’s death should have spelled Hakuji’s end. He would have to atone for his sins.

Yet this slayer, this force of nature, had insisted that he could live to save others.

“Hakuji… Why do you seek death? Is it to escape your past? Is it because you might harm others?”

He did not know.

“You know that when most demons regain their memories, they establish some sort of logic to not feel remorse, to hold their humanity at bay or destroy it entirely.”

It was a statement, not a question. But Hakuji had not known.

“Hakuji. You possess incredible willpower. Despite your past crimes, you have managed to regain your humanity before dying. And I know you wish to help others. I could tell from your scent once I mentioned that you could help. I smelled genuine compassion.”

Despite how mentally weak he felt at this moment, the sun breather relieved some of his self-hatred.

“Please, take my hand. I can make you stop needing human flesh, so that you may stop damaging the world.”

Hakuji held his hand. The pink flames on it receded to accommodate for the gesture.

“Do you want to do this? It will hurt. I know it will.”

“… yes.”

This time, his acceptance was genuine.

A searing pain shot through him as sun-infused blood started flowing through his veins. Falling to the ground, he felt a hand enter his mouth to stop him from screaming, and two others catch him from his back. He was delicately laid on the floor as he slowly became numb to the pain.

The transformation took about a minute. When it ended, and the pain finally receded, a hand pulled him back to his feet. He was greeted by a solemn smile.

“I have done everything in my power. Waxing two has escaped, however. Killing him is not my mission, it’s yours.”

The sun breather addressed everyone else approaching the duo as much as the demon himself.

The hashira bore witness to it, a crippled Ubuyashiki in the tallest one’s hands also listening.

“Muzan is dead. My purpose is fulfilled.”

The slayer sank to his knees, his hand slipping off of Hakuji’s. At that moment, he almost looked frail.

“Hakuji. Take my blood. Use it well. I cannot come back unless there is need of me again.”

He caught his savior’s hand again, and quickly felt buckets’ worth of blood flood into him. In the end, the other demon lay on the ground, what little colour left drained out of his skin, and his eyes closed to the world. His pink flames had stopped burning. However, he still had a pulse. Alive.

Hakuji turned to the hashira and nodded. Nobody objected to his presence.

The sun breather’s lifeless form was taken to the Ubuyashiki mansion, where he got a room to himself. He would lay there as long as a threat the level of Muzan did not exist.

Hakuji and the hashira set off to hunt down the last of the demons.