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Chapter Text

He was hungry...

He was cold ...

He was alone, in the midst of the trash, hidden from the crowd ...

Anyway, nobody would look after him, because nobody cares about an orphan.

Why did he come into the world?

Why didn't he have a family like all the other children?
He could see them walking around in the middle of the market laughing, he could hear the joyful music playing in their hearts, and he was alone ...

Why did he exist?
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"Hello!" A thin voice pulled him out of his contemplation. He looked up.

Squatting in front of him stood a young girl with long dark brown hair. Her blue eyes looked at him tenderly, soft soothing music playing around her. Was she really talking to him?
"Hello," she repeated, confirming that she was talking to him. "Are you alone?"
He nodded.
"What is your name? Me, this is Kaguya."
He looked down. He had no name ... No one had given it to him ...
Some sometimes called him "parasite" or "brat", spitting their contempt because he had the misfortune to be in front of them.

An icy wind blew hard, making him tremble when the air rushed through the thin rags he was wearing. "You are going to catch a cold in being dressed like this"
The teenager took off her peach-colored haori with the motif of small white triangles, revealing the black uniform below, and wrapped his small body. He watched her, stunned by so much attention. As far back as he could remember, He had always been alone, having to fend for himself...

"Huhu, you're so small like that!" She laughed a little, amused to see him so tiny wrapped in the coat.

"This place doesn't seem to be very comfortable ... Are you hungry? Grandpa's dishes are very good, I'm sure you will enjoy them!"
The girl, Kaguya, didn't seem bothered at all by her lack of response. She held out her hand, still smiling. He stared at her.
Did she offer to come with her?
Him?
Really?
Could he?
Did he have the right?
Wouldn't he be alone after all?
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Tears in his eyes, he slipped his little hand, dirty and cold, into the one, warm, held out to him.

Chapter Text

(Eight years later)

"Zenitsu! Get down from there!"

The young boy turned his head towards Jigoro, posted at the foot of the tree he had climbed while trying to catch a sparrow.

"Grandpa!"

"Call me 'master'!" grumbled the old man.

How many times had he said that over the years? Even Kaguya, as the current Pillar of Thunder, called him like that. Zenitsu had definitely acquired this habit through his "big sister".

The sky darkened dangerously...

"Grandpa! I want to catch a sparrow!"

"Why?!"

"For Kaguya-nee-san! She loves them!"

Obviously ...

"Finish your training first" sighed the former Pillar.

Furious rumblings echoed, making them both look up at the clouds.

Suddenly, a lightning bolt struck the tree in which Zenitsu was perched.

"ZENITSU!!!"

***

"... and that's why my hair has been blond for a few weeks."

Kaguya stared at Zenitsu with an incredulous expression on her face when he finished his story during the meal ...

Jigoro sighed and Kaigaku exploded with laughter.

When she asked her little brother why her long black hair ("Why do you want to have long hair?" "I want them to be long like Kaguya-nee-san!" "...") now had this strange color, she had not expected such an answer.

"A user ... of the Lightning Breath ... struck by lightning ..."

Kaigaku laughed even more.

***

He was no longer hungry.

He was no longer cold.

He was no longer alone.

He now had a family he wanted to protect.

He had an older brother for over a year.

He had followed an infernal training with his grandfather and his big sister during more than five years.

And now, at fifteen, he headed with Kaigaku to the Final Selection.

Together, they will become slayers, and together, they can protect their family and all those who need them.

***

"I am so proud of you two!" Kaguya exclaimed, hugging them when they returned from the Selection, Jigoro smiling at his side.

"And you don't even have a scratch! You see grandpa, you said it was too early to teach them the Breath of Absolute Concentration Permanent, who was right, huh?"

The young woman was rewarded with a strike on the back of the head by the old man.

"How old are you to make this kind of remark ?!"

"Twenty three!"

Zenitsu was distracted by a horrible, distorted sound he heard coming. A type of sound that only he could distinguish, that he had heard everywhere in the forest of Mount Fujikasane, the sound of a demon ...

Here?

In the Thunder Estate?

But this sound had a very particular tone which it did not recognize ...

"Is everything ok Zen '?" Kaigaku asked.

"I hear a demon coming ..." he replied thoughtfully. "But there is something weird ..."

In an instant, what he heard in the distance resounded right behind him.

He turned quickly, noticing the horrified looks of his family.

The demon that was there was not any demon ...

A black and purple kimono, long hair tied in a high ponytail, red highlights lit by the moon, a katana at the waist, and above all, three pairs of eyes, the middle of which was engraved with a number ...

Upper Moon One

Chapter Text

Fight!

Fight!

Fight!

Each of his muscles howls, asking for mercy ...

Ignore the pain

Fight!

A stabbing wound burns his face ...
Blood obstructs his sight, invading all his senses ...
His heart rings in his ears ...

Ignore the pain

Get up

Get up!

GET UP AND FIGHT!

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"Eh! Eh! Can you hear me?"

He painfully opened his eyes. When did he pass out?

The blurred vision can only vaguely make him see a silhouette leaning over him. He hears faintly from other people in the vicinity.

"Hold on ok? We take care of you"

Zennitsu closed his eyes again, the orange sky of dawn being painful ...

"Take him right away to the Butterfly Estate!"

"Yes Lady Kochô!"

He lost consciousness after that ...

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Zenitsu woke up in an unknown room. Where was he?

He straightened up on the bed, looking around. His haori was carefully folded on the bedside table, his training katana placed against the wall next to it.
He had been changed and treated, he found when he saw his arms covered with bandages. He could feel others around his legs and abdomen. Another surrounded his head, covering his right eye to his ear. He put his hand on it...

"Don't touch it."

The young boy turned his head towards the source of the voice.

At the entrance was a young woman in a slayer uniform, long black hair framing her face, decorated with two butterfly-shaped pins, the motif of her haori reminding the wings of the insect.

"I am Kochô Kanae, you are currently at the Butterfly Estate." she said softly. "You're already awake when it's only been four days. With all your injuries, anyone would have taken at least two weeks to recover. It's impressive!"

Zenitsu let her speak

"Avoid moving okay? You have deep cuts on your arms and legs and you were almost disemboweled, the slightest movement too sudden may reopen your wounds. You were very lucky not to lose your eye but it will leave a scar. As for your ear ... "

"Kaguya-nee-san, Kaigaku and grandpa aren't here ..." he interrupted, staring at the sheets.

His interlocutor was instantly silent.
It is more a statement than a question. He didn't need her to answer him, he had understood perfectly from the moment he woke up alone.

Zenitsu stood up and grabbed his sword, staggering.

"What are you doing?" asked Kanae. "You mustn't move."

"I know what I have to do ..." he replied in a weak voice before dragging himself outside, using his saber as a crutch.

***

Naively, he believed that happiness could last forever ...

A night...
That's all it took ...

Just one...

It was so absurd ...

Ridiculous...

Disgusting...

Maddening...

All these joyful moments had given way to intense fury. His whole body is bubbling and his heart demands revenge for this injustice.

He felt like he was going to explode if he didn't move.
It was certainly not a good idea with his condition, but the pain that tugged him seemed very slight in the face of the consuming hatred.

His katana was suddenly taken from him, all too easily. Did he lack still a grip? How many times did Grandpa explain to him how to hold a sword?

Useless...

Strange, his hands are tinged with red ...

He tried to retrieve  his weapon, only to find himself face down on the ground. His legs must have let go ...

Pathetic...

He hardly straightened up on his elbows, trembling with anger.

Where do these red dots on the ground come from?

Come on, move ...

He must continue his training, he has no time to rest.

But his limbs still refuse to move ...

Hopeless...

"Your wounds have reopened, Agatsuma-kun" He vaguely heard a female voice.

So what?
This is not a reason to stop training.

A hand was placed on his shoulder.

"You'll end up draining your blood if you don't stop." continued the voice.

So what?

His vision blurred, he felt something run down his cheeks ...Was he crying? Seriously?

Pathetic!

This damn bandage itches. He tried to remove it before being stopped by two other hands, strangely small, firmly gripping his own.

"If you take it off now, you risk losing your sight permanently!" a second voice exclaimed fervently. This one sounds more severe than the first.

So what?

"Your belly points are coming off, they must quickly be redone or your gutss will decorate the garden!"

"It doesn't matter!" he cried and collapsed in tears just after.

Pathetic!

He was really pathetic ...

"All ... Until the last ..." he continued, his voice drowned in tears. "I will exterminate them all to the last! No matter what it costs me! I will kill them all!"

He cried on the floor, ignoring those present.

After a while, he felt that the two women were trying to lift him but he still refused to move.

"Ah, Sanemi-kun..." said the soft voice. "A little help?"

Zenitsu heard this third person approach, then everything was black ...

Chapter Text

The girl responsible for changing his bandages is quite strange, according to Zenitsu.

She keeps giving him nervous looks, opens her mouth to speak before changing her mind and closing her mouth ... And then she starts again ...
This merry-go-round started to annoy him a little.

"If you have something to say, say it." he finally declared after a while.

The girl jumped a little, as if she didn't expect him to speak first ... Or did she imagine to have been discreet and that he hadn't noticed?
She hesitated. Zenitsu let out a long sigh of frustration.

"How did you end up becoming a Slayer?" she blurted out quickly.

He did not expect that.

'How do you feel?' or 'Sorry about what happened to you' were more like the kind of sentences that have been addressed to him since he woke up.
His astonishment must have appeared on his face as she began to stammer.

"Uh, I ... I mean ... Kaguya picked you up, right? How?"

It wasn't something that was asked of him often, and it suited him not to have to talk about it. Even if the answer was short.

"I do not remember." he replied simply.

"H-huh?"

She stared at him with a little embarrassment and passed a hand behind her ear, as if to put a hair back in place ... Which was useless since her hair was perfectly styled in two high quilts fixed by blue butterfly pins .

Now that he paid attention, he felt like he had already seen this girl somewhere ...

"I don't have any memories until Kaguya finds me." he clarified.

It was always so strange to say. Without memories, it was as if he didn't exist ... That day, he couldn't remember either his name or his family ... Or even if he had one ...

"Hm, you have a very bad head wound ..." Kaguya had said while combing his hair after washing him the day she took him. "Do you remember how you did that?"

The little boy could just shake his head negatively.

"Hm, strange ... And your name? Do you remember? "

New negation. She frowned.
The teenager took the rag that had served as clothing.

"It seemed to me, though, that I saw something when I took it off ..." she mumbled, lost in thought. "Ah! Here! ... Hm, hmmm ... Waga ...? Wasta ...? Ah no, Agatsuma actually. And then ... Hmm ... Zen ... Zenitsu? Yes, it must be that!" She nodded vigorously, satisfied, then realized she was being watched. "Oh sorry!" she laughed. "Don't worry, it happens to me often! See the embroidered kanjis here?" She showed the white wire writings on the garment. "It says 'Agatsuma Zenitsu', it must be your name ... Well, I guess ..." she added, more to herself.

The child stared curiously at her as she gently stroked his hair.

"Don't worry too much ok? It doesn't matter if you don't remember. When the time come, it will come back to you!"

From time to time, he had dreams, filled with bright colors, the same sound coming back each time. This sound was the only thing distinct in these dreams, the rest being far too vague.

Many years have passed now, but Zenitsu still did not remember ... There is just this sound, and the feeling that it is important...

"Are you OK?" The girl pulled him from his contemplation.

Ah, he must have been silent a little too long ...

"Yes, yes, it's okay. No need to worry! How about you? How did you get here?"

He tried to change the subject.

"Uh ... nothing special ... I lived with my family and one night a demon came. Shinobu-sama eliminated him before he attacked me and afterwards she offered to join the Estate. This is ... just an ordinary story among the Slayers ... "The melancholy could be read in her eyes.

Zenitsu regretted having asked the question. Quick, something!

"Um! Uh, haven't we seen each other somewhere already?" he said, awkwardly.

"Ah?" She stared at him.

"Well, since a while ago, I feel like I've seen you before but I can't remember where .. haha ..." He stammered.

She continued to stare at him for a while, a little too long for his liking.

"Are you kidding me ?!" she said suddenly, as if she was upset that he asked.

"Uh no?" He hesitated.

"The Selection!" she got carried away. "We passed the Selection at the same time! You saved me! I even stayed with you after that!"

Did he really do that?
Zenitsu thought for a moment. Ah!

"The whining girl who couldn't move!" He clapped his fist in his hand. "Uh, Aoi, right?"

"Whining !?" She sighed deeply. "Ah, it doesn't matter." Aoi looked annoyed but quickly recovered. "It doesn't matter ... Thanks again for saving me ..."

Zenitsu thought she didn't have to thank him again but before he could say something, the door opened.

"Have you finished the bandages, Aoi? "Asked Shinobu, entering with her eternal grumpy face.

"Just now." replied the latter. Shinobu inspected her work.

"Well done." she said, softening. "How are you feeling, Agatsuma? Physically I mean... Are you still hurting somewhere?"

"It's okay." said the adolescent vaguely. His stomach still pulled him from time to time but remained largely bearable, the other cuts were painless. The worst was the one on his eye ... He put his hand on it.

"Don't touch it!" exclaimed the two women at the same time.

"It itches ok ?!" he replied annoyingly. This gesture was beginning to be purely unconscious. "I'm going back to my room. I guess I still can't train?"

"Do that and I will put you on sedation!" threatened Shinobu, absolutely terrifying despite her small size.

"Yeah, yeah ..." he sighed before leaving the room, knowing full well that she would do so without hesitation. Even if he remained limited in his movements, he was at least no longer bedridden.

Crossing the Estate, he was interrupted.

"Agatsuma-kun."

Zenitsu froze.

If he really did not want the Pillars to see the failure he was, there was one he could no longer face ...
He had forgotten, for a moment ...

"I'm relieved. Kanae told me that your healing was going well ..." He could hear all the sincerity in that voice ...

"It's nice to worry about me, Himejima-san ..." thankfully, his own voice didn't shake.

"It's normal ..." The presence of the Stone Pillar was still soothing. Zenitsu felt him approach.

"Everyone's worried after what happened ..." the man said calmly, placing a friendly hand on his shoulder.

He did not deserve all this attention for one second ... He had forgotten that he was not alone in having to go through this ordeal. Kaguya was appreciated, inevitably all the Pillars also tried to mourn ... And in particular Himejima ...

At that moment, Zenitsu realized that he would never hear the harmony that there was between Himejima and Kaguya ... The two of them, that was ...
Ah yes ... that too ...

"Nee-san, there is a new sound in you." announced Zenitsu, a little before the Selection.

Kaguya had blushed furiously.

"You keep that for yourself for the moment, okay?It's up to me to tell him!"

The tender and happy smile Kaguya had when she said this was absolutely beautiful.

But, in the end, she will never have the opportunity to announce it.

And Zenitsu couldn't cope with Himejima, not after that ...
It was better if he never learned it ... He will make sure he never learns it. Absolutely no one should know.

"Are you sure you're okay, Agatsuma? You're very quiet ..."

He didn't deserve a second for Himejima to worry about him.

"Yes, I am fine." His throat is so tight that it's hard to talk. "I ... am a little tired and ... my wounds are still painful ..."

Lies.

"Hm, it would be better if you went back to rest."

"Yes..."

"I will pray for your recovery."

Don't do this, don't waste a single moment for me! 

"Thank you, Himejima-san..."

Zenitsu returned to his room with a heavy heart. He refrains with all his might not to cry, he has no right to do so. His jaw was already starting to hurt ...

During the entire exchange, he hadn't looked at Himejima once, he couldn't ... He couldn't look at him ...

He couldn't face Himejima knowing that, that night, the heart that stopped in Kaguya was not only hers ...but also a tiny other one...

Chapter Text

As soon as Aoi announced that his wounds had healed, Zenitsu started training.
He still had to keep the bandages on his eye for a while to make sure there was no risk of him losing his sight, but at least that didn't stop him from moving. After all, Grandpa and Kaguya had repeatedly made him practice with a blindfold, forcing him to trust only his hearing, so seeing only with one eye was not a problem.

He trains again and again, always more, always pushing his limits, until his legs give him up, until he has the impression that his arms will tear off ... Until he spits blood under the effort.
Kanae and Shinobu were forced to inject him with sedatives so that he could rest. Aoi had lectured him when he woke up... (He had to make sure they didn't surprise him in this state anymore.)

"Okay, I'll take the bandage off." warns Shinobu, preparing various antiseptics.

"Definitely?" Zenitsu asked, sitting on the clinic stool. If he could finally get rid of this damn bandage, that would relieve him. It still itched horribly.

She let out a long annoyed sigh.

"Yes, Agatsuma-kun, definitely. It's been two months now, your eye is no longer at risk."

Yeah, that's not what she said yesterday when she caught him scratching it.

The boy closed his eyes and let the doctor remove the bandage and clean the wound one last time.
When he opened them again, the expression he saw on Shinobu's face was unreadable.

"What?" he asked, frustrated.

"Well, you have a scar ..." she replied flatly.

Zenitsu swallowed his annoyance.

"I suspect." he said, grabbing the mirror the young woman held out to him.

He was missing an upper part of his ear, cut clean in the shape of a crescent.
The mark now crossing his face started from his forehead, traversed his temple as well as his right eye in several ramifications, stopping in the middle of his cheek.
Simply put, he literally had a lightning bolt printed on his face.

"How appropriate ..." he said with an almost mad laugh.

***

Finally, after two months of recovery (wasted time), Zenitsu could resume training as he wanted. More or less...

Kanae, Shinobu and Aoi had been very clear about this: if he coughed up blood again, it was good for forced rest for at least a week. (But if you don't know that, you can't force me)

"Kof ... Kof ... Urgh ..."

He still forced too much, didn't he?
At least this time it was only a few drops that he could easily cover with the soil from the garden.

Then he heard very special small, felted steps.

The boy quickly turned and found himself facing Kanao, a look of panic on her face. No need to lie to her, she had certainly seen it.

"You ... you are bleeding ..." she said in a trembling voice before placing her hands on her mouth, as if having dared to speak was a vile crime.

"Wait!" exclaimed Zenitsu, grabbing her wrist as she was about to leave, surely to warn one of the nurses in the Estate, if she did not go directly to warn Shinobu ... "Don't tell anyone, please..."

Kanao's gaze silently questioned him.

"I've lost enough time like this" he whispered, letting go of her. "I have to train, go on a mission, get stronger ..."

A new why passed between them.

"... Kanao... How would you feel if Kanae or Shinobu died at the hand of an Upper Moon?"

The girl stared at him, completely horrified and mute.

He knew it was a cruel assumption for the teenager who had already suffered so much. No need to be a genius to understand it, it was enough to see her constant hesitation, her difficulties in expressing herself, masked behind a calm and posed smile which was nothing more than a mask.

She was twisting the edges of her kimono, sweaty, staring at the floor. The idea of losing one of her sisters, whoever she loved, was unbearable to her.

The worst part is that it could have happened ...

Kanao remembered that day three years ago when Shinobu came back in a panic with Kakushis carrying Kanae and Kaguya, both injured and bloodied following a clash with an Upper Moon.
What if Kanae had been alone on this mission? She would simply have been killed, she had said it herself...

Emotions were still a fuzzy concept for Kanao, but if her big sister had been killed that day, she would most certainly want the culprit to pay.

"Sorry to say something so awful." said the blond. "But ... you understand now ..."

It wasn't a question, but she nodded anyway. She wouldn't say anything as he asked. Besides, it was just a tiny bit of blood, so it wasn't so bad was it?

"Thank you" he said, resuming his saber training.

Kanao watched her for a moment, then took a particular piece from her pocket which she threw in the air, spinning it, before catching it and judging the result. Tails.

"Can we train together?" asked the girl.

Zenitsu considered her for a moment ... It was a good idea, Kanao seemed rather strong and training alone had its limits.

"OK"

***

Finally, he received his own katana. Finally, he was going to be able to go on a mission.

Sitting opposite the blacksmith who came to deliver the weapon, Zenitsu took it carefully, Kanae observing the scene in silence.
The scabbard was ivory white, perfectly accompanying the white and yellow handle. The guard was simple, cloud-like, with a discreet triangle pattern. He appreciates this sleek design.
Under the blacksmith's eagerness, the teenager drew the sword.

After a few moments, the grayish blade gradually became golden, bright, as if it were made directly from lightning.
The blacksmith was ecstatic, clearly happy with the hue adopted by the sword.

"A very good color for a user of the Lightning Breath!" exclaimed the latter. "But this is the first time I have seen a katana become so dazzling!

Really? Zenitsu supposed it was a good thing, grandpa and Kaguya had had a golden saber too.

The boy felt something settle on his head.

"Chu!"

He recognized the distinct sound of Chuntaro, his messenger sparrow which he had received at the end of the Selection.

The mission order carried by the bird told him to go quickly to the North-West where strange disappearances of teenagers had taken place for some time.
Zenitsu wondered if it was prudent to send a Mizunoto to a place where this phenomenon had been happening for some time ...
Anyway, it was better not to hang around.

The blonde dressed in his slayer uniform, trying not to look at the multiple scars now covering his body, and put on his yellow haori, Kanae helping him fix his long hair in a high ponytail with a red cord.

"You can come back to the Estate as soon as you wish" she said to him when he left.

"Thank you for your hospitality ..." he replied simply. It was time for him to leave.

The young boy addressed the sparrow perched on his shoulder.

"Are you ready Chuntaro?"

"Chu!"

The bird replied with determination and took off, followed closely by his slayer.

Chapter Text

"Hey, hey, did you hear that rumor about the Pillar of Thunder?" A slayer asked his makeshift companions one day.

Chapter Text

Meeting this pink-eyed demon had been like being struck by lightning a second time ... However, Zenitsu couldn't decide whether this was a good thing or not.

***

Tanjiro was freaking out, watching nervously as Nezuko was tracing the dark scar on the Hashira's face, and the latter was just eyeing her curiously, some amusement also.
The redhead was lost; what was happening?!

He just remembered being knocked out by the blond after he said that he had to bury the corpses lying in the demon's house; the Hashira hadn't been pleased, called him an idiot because he shouldn't aggrave his state... and then, Tanjiro woke up in a futon, the blond and the masked slayer - Inosuke Hashibira, apparently, or so, that was what he had told in his fight against the Pillar - were just beside him, in a Wisteria House.

Having no idea how he ended up there, Tanjiro could only guess that the blond had carried the both of them... That was embarrasing... But the worse was probably that, as night was already advanced, Nezuko got out of her box while he was still sleeping, and now... well...

"Nezuko!" he called "Stop that!"

She turned to him and blinked lazily, then she reported her attention to the scar, much to Tanjiro's chagrin. He could only hope that the other boy doesn't lose patience.

"She's been doing that for a while now..." the latter sighed.

"I'm really sorry!"

"I don't particulary mind. Who is she for you?"

"Tha's my little sister..." Tanjiro answered warily, tensing as Nezuko started to play with the long golden locks, a fascinated look remplacing the usual blank stare. "But, I swear, she had never hurt anyone! That won't happen!" he hastened to add.

"I see... Nezuko that's it? Well, I'm Agatsuma Zenitsu." He patted her head, a soft amused smile on his lips. "Nice to meet you, Nezuko-chan."

Tanjiro sighed in relief. He finally knew the name of this slayer, who was still unbothered by his sister's attitude, giving off a peacefull scent that reminded the redhead the time when he was surronded by his many siblings. Maybe that person had had siblings too before becoming a slayer? That seemed logical...

The serenity of the moment was broken by a loud snoring of Inosuke. Tanjiro sweatdropped.

"You have broken ribs, go back to sleep..." the Pillar ordered softly.

He did so, at ease, knowing that nothing would happen to Nezuko.

When he woke up again, his little sister was quielty asleep in her box, and Zenitsu was long gone...
Inosuke complained loudly, wanting to fight again the Hashira who had broken four of his ribs. Tanjiro thought it probably wasn't a good idea...

***

Several days later, Zenitsu found himself summoned to the Headquarters, accompanied by another Pillar, yet another to whom he would prefer not to show his face.
The moon was already high in the sky, Makomo was waiting for him, reconizable with her flowery pink haori and her low bun held by a hairpin adorned with small blue flowers.

Even though the sound of the Water Hashira hadn't really changed since that... incident, Zenitsu was certain she hated him. His position was blatant proof of his incompetence, and Makomo had every reason to be angry at him; she and Kaguya had participed at the final Selection together, becoming best friends by slayin a large misshapen demon, had shared many missions, achieved the rank of Pillar at the same time... and Kaguya had died protecting him...
Makomo hated him probably as much as he hated himself. After all, he was so weak that he still couldn't get rid of this fever who had started after the attack, he coughed blood at nearly every training... and no matters how long or how hard he trained himself, he was still far behind every other Hashira, still the weakest of them.
So, he preferred to keep his interactions with them as minimal as possible, trying to made himself small at meetings, barely talking.

The mansion of Oyakata-sama was still as grandiose, making him feel even more out of place.
He took his place near Makomo, hiding his uneasyness, and stared at the back of their Master, waiting for instructions.

"Hmm, so many children have already been killed..." stated the black haired man, petting a exhausted crow. "Maybe it's the work of a Demon Moon?" 

The teenager felt his fingers twitch involuntarily and the anger grow in his throat at these words.

"Zenitsu, Makomo..."

"Yes!"

***

"The moon is high and bright tonight..." observed the Water Pillar while they run in the wood of Mount Natagumo.

"It is." Zenitsu responded absently.

"So cold!" she chirpped. "I miss the time you were babbling about your day!"

He didn't react at the jab.

"We have to slay the demon before it kill someone else." The blond declared sternly.

"Yes, yes... I will go that way then."

He nodded and the two Pillars separated.

***

Zenitsu's memories started when he was approximately seven years old, when Kaguya took him in.
Before that, he can't remember anything except for these bright and blurry colors, and this sound filled with hate, envy and despair.
Kaguya and Jigoro never asked him to become a slayer, he asked that they train him after he picked Kaguya's katana out of curiosity.
At that moment, his mind turned blank, an abysmal and incomprehensible wrath ran through his veins. He didn't understood where this feeling was coming from, he just knew that he would one day find the answers by becoming a slayer.

So far, every demon encountered had the same disgusting, condescending sound, with no regard for the lifes they snatched away. Exactly like this spider demon who turned its victims into puppets without will of their own, a misshapen head with spider legs.

Disgusting.

He could just hope that the Kochou sisters would be able to do something for all the slayers transformed. At least, with the demon now dead, there will be no more victims.

Zenitsu goes further into the mountain, the gloomy aura becoming more and more thick.
The Pillar started to ear the sound of a battle, and a Lower Moon... He accelerated his race, feeling the lightning clack around him.
He stepped right in time to see a dome of red strings starting to cut the unfortunate slayer wearing a familiar green checkered haori.

Breath of Thunder
Third Form
Thunder Swarm

The wave of his blade broke the death trap, freeing Tanjiro who let out a breath of relief.

"Tch! Another one!" spat the demon.

It was small, with white hair and red eyes, wearing a white kimono with a spider web motif.

'A child' noted Zenitsu.

Inded a child, but still a demon under this frail stature.

"Lower Moon Five huh..." He noticed after seeing the number inscribed in its eye. "Again a number Five... It's the fourth already."

Behind him, Tanjiro gasped in amazement.

"I have a question for you, Lower Moon."

The demon gritted its teeth.

"Why should I listen to you?!"

"Do you know where the Upper Moon One is?"

The demon frozen, its eyes widened.

"Upper Moon One?" It repeated, baffled for a moment before turning angry. "Why? Are you in such a hurry to die?!"

"I guess that means you don't know..." Zenitsu cut off its neck in the blink of an eye. "Die then."

Endless sadness echoed through the demon's body as the demon turned to ashes, walking slowly towards Tanjiro and his sister. Zenitsu frowned and watched the scene cautiously, ready to cut it out again at the slightest suspicion. But nothing happened, the body fell in front of the siblings, Tanjiro placed a hand on their back, his eyes filled with tears. The demon finally disappears in the wind.

The Hashira walked over to them, not caring that he was stepping on the demon's kimono.

"There is no point in taking pity on them."

Apparently that did not please the boy with the burgundy hair.

"Agatsuma-san, please move." he asked firmly.

The blond stared at him in annoyance.

"Even though they have a child's body, they are still monsters who have devoured dozens of innocent people."

Tanjiro seemed determined to make his case.

"Don't get me wrong! I will never leave any demon alive, if only to avenge the innocents they killed! However, before they became demons, they were also humans like us! sad beings whose existence is doomed only to despair! "

Zenitsu was starting to become angry at his words. Was he really serious? It was no longer naivety but idiocy at this point ...

"So what?" the Pillar asked, his cold tone leaving no room for an answer. "They are murderers, nothing more. Because they are suddenly remorseful at the moment of their death, they are worthy of compassion? Don't make me laugh! Did they have regard for the people they slaughtered? No, they did these acts with full awareness and enjoyment. Burning in hell is all they deserve."

The redhead looked pained, watching his interlocutor with a mixture of anger and sadness.

"If that's what you think, then why did you spare Nezuko? Surely you already knew about her the first time we met ..."

"Yes, I knew from the first second…" He sighed. "However, in her sound, she doesn't have that thirst for blood that all demons have. You told me she never hurt anyone and never would. I just decided to believe you ... She's still innocent, make sure that is always the case."

Tanjiro looked down and nodded. He sounded ... confused, bitter, tearful ...

Weird.

Suddenly, Zenitsu stepped over them, unsheathing his saber and his golden blade deflected a pink blade that was rushing towards Nezuko. Thus appeared a young girl, about the same age as them, with hair styled in a side ponytail held by a fuschia butterfly hairpin.

"Put away your sword, Kanao." ordered the Pillar.

She hesitated for a moment, her gaze juggling between the blonde and the two siblings before finally complying.

"Oh! Agatsuma-kun, you're already here!" Makomo's thin voice rose behind his back as Makomo entered the clearing. "Ah, Kanao-chan is here too!" she smiles pleasantly.

The Water Pillar's detached demeanor looked suspicious to Zenitsu. He stared at her harshly but she didn't react, still smiling as the atmosphere grew tense.

A crow circled in the air above them and abruptly announced:

"Message from Headquarters!" he croaked. “Grab Tanjiro Kamado and Nezuko, and take them to Headquarters! Nezuko the demon wears a pink kimono and has a piece of bamboo in its mouth! Tanjiro wears a green checkered haori and has a scar on his forehead! They must be brought to Headquarters!"

Chapter Text

Tanjiro slowly regained consciousness, not even realizing that he had collapsed from exhaustion after his fight with the Lower Moon and the altercation with the Pillar of Thunder.

He was on someone's back. It was warm, comfortable, a few strands of long hair that tickled his face every now and then ... It had been a long time since he had felt so good, so ... safe ... just like with...

"Dad ..." he whispered, trying to snuggle more into that warm, strong back.

... and then he was suddenly hit in the back of the head, waking him up.

"Have a little respect, brat!" the male voice of a hooded figure screamed at him, hitting him a second time. "Agatsuma-dono honors you by carrying you and that's how you talk to him !? Apologize!"

"So .. Sorry .." he stammered, flushing with embarrassment.

Zenitsu had turned to him for a fraction of a second, surprised before putting on a neutral face again, as if that didn't fazzed him more than that. Tanjiro buried his face in his hands once he put him down.

'I can't believe I just called a Pillar 'dad'... It's so embarrassing ! We must be the same age... I want to bury myself in a hole ...'

"Ara ~ Ara ~ It was a comfortable trip for Tanjiro, I would say!" Makomo said cheerfully.

"Please, Makomo-san, don't add any more ..." he begged, mortified that everyone had heard him.

The other two women present, one with green and pink hair, the other with a colorful haori and two pink butterfly hairpins, giggled gleefully, failing miserably in their attempt to be discreet. A man in a striped haori had buried his face in one hand, shoulders shaking with silent laughter. Two others were laughing without restraint, the tall one with white hair slapping the shoulder of the one with the fiery hair. The teenager seemed disinterested and the last one, towering over everyone else, seemed dismayed by his colleagues

Agatsuma sighed in annoyance and Tanjiro finally realized that he didn't see Nezuko's box anywhere. Where was he even?

Seeming to perceive his confusion, Makomo informed him.

"You are at Demon Slayers Headquarters, Tanjiro. Your trial will begin soon."

A trial? Why?

"It's not necessary!" exclaimed the fiery man. "Leaving a demon alive is a clear violation of the rules! They must be executed without delay!"

"Let me cut off the demon's head. The blood will spurt out flambloyantly!" the silver-haired one added, already grabbing his two sabers.

"Eh? Do we really have to execute such a cute kid?" lamented the one with the pink hair.

"Rengoku-san! Uzui-san! We cannot afford to make hasty decisions." The woman with the butterfly hairpins intervenes. "I'd like to hear this boy's story."

Under the encouraging gaze of the Water Pillar, Tanjiro endeavored to recount that horrific incident of two years ago, how he found his entire family murdered during his absence, Nezuko's transformation and how she struggled with her thirst for blood and had never harmed anyone ... However, this last information was greeted with the greatest disbelief and suspicion.

"What I would like to know the most ..." intervenes the man with the odd eyes, pointing an accusing finger. "... is how Makomo is going to be punished? How is she going to take responsibility? As well as everyone who knew about the demoness? And why is she not attached, or even this boy?"

"She came of her own free will, without opposition, to tie her up would have been excessive, don't you think, Iguro-san?" declared the Thunder Pillar. "Tanjiro was unconscious, it was unnecessary. It's not like he's a threat after all."

Tanjiro was slightly offended by Agatsuma's implication of his supposed weakness. He knew! No need to add more!

He was still reassured to know that the blond seemed to be on their side.

"What's the matter with you, Zenitsu?" Iguro continued in an angry tone, but his interlocutor contented himself with staring at him in turn. The Serpent Pillar frowned, Tanjiro could smell the scent of discontent emanating from him.

The others Pillars watched the scene for a moment, then resumed their conversation regarding Nezuko's fate. The Flower Hashira seemed to accept the idea that his sister could also be a slayer as well as a demon, lightly supported by the Love Hashira who was the only one to assume that the master had to be aware of the situation and that it was better to wait until his arrival before making a decision earning her a few annoyed glance from some.

"Say, Zenitsu-kun, where is your haori?" questioned the black haired woman, making her way towards them, a glint of amused curiosity in her lavander eyes. "Usually you never part with it..."

"That's..." started the blond but he was interrupted when a scarred man with white hair arrived, holding the box of Nezuko in his hand.

"So here's the idiot walking around with a demon." he declared haughtily. "Do you still have a lot of genius ideas like this?"

"I thought I asked for her to be brought to safety ..." Zenitsu huffed, giving a stern look at the kakushis following the Pillar of the Wind.

"We are terribly sorry, Agatsuma-dono!" begged the latter, trembling.

"Don't touch this box, Shinazugawa-san." Makomo proclaimed in a strict tone.

He ignored her.

"You say a demon is ready to fight alongside the slayers ..." He reached for his katana. "... to defend humans? But come on, this is completely absurd, kid!"

Chapter Text

Feverish hands cleverly intertwined the flower stalks, gradually forming a colourful crown.

Beside him, the small form carefully observed the precise gestures, then tried to reproduce them. However, no flower lasted for more than a few seconds.

The child pouted, disappointed. The teenager's hand stopped working to stroke her head.

"Don't worry, it just takes a little practice." He encouraged. "I know you'll get there eventually."

She nodded, her determination renewed and picked up new flowers.

"What are you two doing here ?!" a new voice interrupted them, also belonging to a teenage girl.

The boy turned to her, responding nonchalantly.

"I am teaching her how to make a flower crown, as I had promised."

The child tilted her head questioningly.

"A flower crown?" the teenager raised an eyebrow. "You can teach her later! You're supposed to be in bed!"

With that, she grabbed the boy’s hand, forcing him to stand up and dragged him towards the building, the child at their heels.

She took him to a bedroom where she urged him to lie down on one of the beds before pulling the blanket up to his chin.

"Don't you dare get up until tomorrow morning!"

"But, I promised ..." he complains lightly.

"Yes, yes, I got it." The girl scolded. "However one more day will not change anything, you are sick."

A moment passed.

"Are you angry?" he asked sadly.

"Not really..."

"Sorry, is it because I fell in the pond last time? I didn't do it on purpose ... it's because ... she was going to fall ... and she is .. . too small to swim ... "

The young girl observed him, the child on her knees let out a small sound of confusion.

"I understand." she says. "Sleep now, your fever is still high."

"Hmm, good night, Nee-san ..."

"... Good night."

***

‘The crisis is over’ thought Aoi while massaging her temple, now sitting on a chair next to the blond’s bed.

Zen’itsu's sleepwalking, coupled with his interminable fever, made for some peculiar scenes, with its share of inconsistent talk and most of the time no one had the slightest idea what he was talking about. 

So, when a resident of the Butterfly Estate - because for some reason, the Thunder Pillar preferred to get some sleep there than in his own Estate - came across a sleepwalking Zen’itsu, the directive was simple : go with whatever he was saying until you managed to drag him back to bed.

Unfortunately for Aoi, she was usually the one who had to do this task the most, but fortunately, Zen’itsu was quite tame during those moments and followed her without too much resistance. The other girls didn't have such a chance.

She let out a heavy sigh again.  Nezuko, in her child form on her lap, started to pull at her sleeve, pointing towards the sleeping Zen’itsu and tilting her head in question, as if the demon girl was asking her what he meant earlier.

“Sorry, Nezuko, I don’t know what he was talking about…” the teenage girl lamented. “Did he ever talk to you about flower crowns or something?”

As Aoi suspected, Nezuko shakes her head negatively.

‘Who the hell is he seeing when he is in such a state? He’s clearly hallucinating…’ she pondered, frowning. ‘When he talks about a nee-san, that could possibly be Kaguya-sama? But what about a child? This isn’t a secret that Zen’itsu was amnesiac when the previous Thunder Pillar took him in… What could that mean?’

“You’re really confusing, you know that?” she addressed the Pillar, sighing again.

They stayed in silence for a while, only perturbed by Zen’itsu sleeping sound.

“Nezuko? Are you here?” a yell-whisper came from the door, the recognizable red hair of Tanjiro peeking in the doorframe.

The demoness turned in his direction before sliding from Aoi’s lap and rushing to her brother who hugged her once she was near reach.

The nurse got up and left the room with the other two, closing the door behind.

“Is everything alright with Agatsuma-san?” inquired Tanjiro.

“Nothing really out of the ordinary concerning him.” she answered. “Why? Did something weird happen?”

“Hm, I’m not sure… He just came and asked Nezuko if she wanted to see a flower field near here… But he seemed … kinda out of it? I’m unsure of how to put this. I don’t think he registered that I was also present. I don’t know if that makes sense…”

Aoi shook her head.

“Don’t worry, I understand what you mean. To put it simply, Zen’itsu sometimes get some  hallucinations. No one knows what he is seeing or talking about. It never involved a child until now, so I think that Nezuko’s presence have triggered a new one.”

“Eeh, really?! I’m sorry!”

“It’s fine, he is as harmless as a kitten in this state. Keep in mind that you may encounter him like this again, don’t take it too personally if he ignores you. You may call for me if you can’t handle him.”

***

Some weeks later, as Tanjiro was busy trying to master Total Concentration Breathing Constant with the help of Naho, Sumi and Kiyo, he was suddenly interrupted by a commotion coming from the entrance of the Butterfly Estate.

Intrigued, he goes to check what was happening, partially hidden behind the wall.

“STOP AVOIDING ME!” a boisterous voice resonated angrily.

The yell was from a tall teenage boy with black hair styled a mohawk, but as he was turning his back on Tanjiro, the latter couldn’t place who it was, only that he seemed angry at the Thunder Pillar who was accompanied by a carbon copy of the Flame Pillar that he has seen during his trial, only younger. Tanjiro was pretty sure he had seen this boy at the Selection.

“... I’m not avoiding you.” responded the Pillar flatly.

“Stop kidding me! You just arrive here, see me and turn around! It looks like you’re running away!”

The younger boy watched the two, seeming unsure what to do.

Agatsuma’s frown deepened.

“I don’t have time for this.” he said and departed so quickly Tanjiro would have swore he just vanished.

“Sorry about him…” the boy bowed to the other before leaving too.

Left alone, the tall boy yelled in frustration, punching the wall.

‘That seemed pretty intense…’ thought Tanjiro.

However, watching the now retreating figure, hunched in defeat, he just looked sad and lonely to the red-haired boy.

***

"Genya, do you want to come with us for our next mission?" Tanjiro asked Genya with his usual enthusiasm. 

"Why are you talking to me? And how do you know me?!" replied the teenager angrily. 

"I just asked the girls at the Domain." The redhead replied.

He tilted his head in confusion; he had offered to accompany him, Nezuko and Inosuke, to their new assignment which he knew from Shinobu that they had to join the Pillar of Thunder and its tsuguko in order to lend a hand in their own mission.

 He had thought it was a good idea for Genya to come as well since the latter seemed to have some things to settle with the Pillar. 

"Just because you know my name doesn't mean we're friends!" Genya spat before continuing on his way. 

"Hold on!" Tanjiro shouted. "We're going to join Agatsuma-san and Senjuro-kun on their mission! You want to talk with him, no? This is a good opportunity!" 

His announcement made his interlocutor stop in his tracks. 

"You..." the slayer turned to him with a fierce look. "I don't know what you think you know but you better stop, you're just annoying." He disappeared around the corner of the hallway. 

This left Tanjiro a little dumbfounded. 

He thought he was doing well but Genya was indeed right, he didn't know why those two were at odds. From what little he had heard during their altercation, they had once had a good relationship but something had happened that had soured it. 

Suspecting that neither of them would provide him with an explanation, Tanjiro decided that Kanae, with her sweet personality, was best able to inform him. Maybe he should have started there... 

"It's probably because Zen'itsu feels guilty for Kaguya-san's death." said the Flower Pillar vaguely. 

Tanjiro was equally troubled. 

"Hmm, I'm sorry but I don't get the connection..." 

"Oh? You don't know?'' She looked pained. "I thought Makomo-san would have told you about it since she also trained you." The young woman put a hand on her cheek, pensive. "To put it simply, Kaguya-san was the previous Thunder Pillar and also Zen'itsu's adopted big sister... However, about a year ago, the Thunder Estate was attacked by an Upper Moon. Zen'itsu is the only one who survived.... No one knows how this Upper Moon managed to find the Domain." 

Tanjiro listened eagerly, gulping at the knowledge that a boy of the same age had stood up to an Upper Moon when he had narrowly missed being killed by a Lower Moon. 

"..." Kanae seemed to hesitate for a moment to explain the rest to him. "Kaguya-san...had a relationship with Himejima-san, the Stone Pillar, you know who I'm talking about, right?" He nodded. "He was the one who took in Genya back then, so he and Zenitsu have known each other for a long time. They were really good friends..." She lowered her eyes sadly. "...Before this incident, Zen'itsu was a cheerful, fairly easy-going boy, his hallucinations aside, but now,...ah, well, you know. He avoids us, not just Genya , and spends all his time chasing demons without a break...I think something broke inside him that night." 

Tanjiro lowered his eyes in turn, frowing. 

When he was still training at Mount Sagiri, he remembered being woken up with a start one night by the loud, alerted cawing of a crow; Makomo had bolted up and left so quickly she was just a blur, Sabito and Giyuu struggling to follow. However, Tanjiro hadn’t been able to catch what the crow had said and, at that moment, he hadn’t thought to ask Urokodaki for information.

The next day, Makomo’s scent was so wrapped in such hate and anger he was genuinely terrified to even say a word to her. Sabito just let him know she just lost someone important.

***

Criiick

Her teacup cracked under her grasp.

She took a deep breath, trying to calm herself down.

'Calm down, calm down, Makomo, you're not a child anymore' she repeated to herself. 'Remember what Kaguya said: if you are angry, be angry after the battle, now you have no room for error! One mistake and only death awaits you!'

The young woman gritted her teeth in annoyance, breaking the cup for good.

She turned her head towards the night sky, ignoring the liquid burning her hand.

'Zen'itsu...he's starting a new mission, I think...I have a bad feeling.'