Chapter Text
"Izuku! Watch this!"
I was five. My biggest concern was how high I could swing and whether I could beat my brother in tag. The sun was hot, the air thick with summer. Kids laughed. The world was simple. Until I opened my mouth to call out—and the sky answered back in flame.
One breath. That's all it took.
A gust of heat roared from my throat like the scream of a monster, curling over the grass in wild, hissing ribbons. The playground scorched. Metal blistered. The air stank like melted plastic and smoke. And in the middle of it all, my twin brother stood frozen, his eyes wide with something I didn't want to name.
Fear.
That was the last day I ever saw myself as normal.
Less than an hour later, the smell of antiseptic clung to the air—sharp, sterile, and way too clean. I sat on the edge of the examination bed, my legs swinging back and forth, heels knocking softly against the cold metal. Izuku sat next to me, hands folded tightly in his lap. He kept glancing between me and the doctor, like he was waiting for something to explode.
Mum was smiling. Sort of. It was the kind of smile that looked okay if you didn't look too closely—except I did. I saw the little tremble in her chin, the way her fingers clenched around her purse strap like she needed to anchor herself to something.
"It's... remarkable," the doctor said finally, flipping a glowing chart around to face us. "What your daughter produces isn't typical fire. It's something closer to chlorine trifluoride. Highly reactive. It ignites nearly everything—glass, brick, even some metals. One of the most dangerous substances known to man."
Mum's smile cracked. Izuku's mouth fell open, stunned.
"She has built-in resistance," the doctor went on. "Her lungs, throat, even her teeth seem to be adapted. Her skin's tensile strength is... frankly, abnormal."
He paused, tapping his pen against the clipboard like he didn't want to keep going.
"She's a biological anomaly. Brilliant, yes. But volatile."
I tilted my head and asked, "So I'm a dragon?"
The doctor blinked. "Well... yes, in a way."
Izuku's eyes lit up, and he gave me a little nudge with his elbow. "That's kinda cool."
"It's not just cool, Izuku," Mum said gently, reaching over to tuck some hair behind my ear. "It means we have to be very careful."
The doctor nodded, somber again. "She could burn through an entire building if she so much as hiccupped wrong. This kind of quirk... without control or structure..."
He didn't finish the sentence.
But I heard it anyway.
I could hurt people.
I stared down at my hands. They looked small. Normal. They didn't look like weapons.
But maybe they were.
"I don't want to hurt anyone," I whispered.
Mum took my hand in hers—warm, steady, shaking just a little. "That's why we'll figure this out. Together."
The doctor's words were still bouncing around in my head, like hot embers that refused to cool.
"She produces something similar to chlorine trifluoride... ignites nearly everything... built-in resistance... volatile..."
Volatile.
That one stuck.
I didn't cry in the office. Not even when Mum reached for my hand and gave me that look—gentle, but afraid. I just nodded, like a good girl, legs swinging off the table while Izuku sat beside me, eyes wide like I might catch fire any second.
Later that night, the apartment felt too small, mum had a visitor come earlier so she put us to bed a little while ago. Izuku was asleep, curled up in bed across the hall, but I couldn't rest. I could still smell the melted plastic from the park. Still see the way people screamed and scattered—mothers pulling their kids away from me like I was some kind of monster.
I didn't mean to. I didn't mean to.
Then I heard Mum's voice—low and tight with frustration—coming from the kitchen.
"No, Kenji, I'm not just handing her over to you like she's some kind of...project!"
I crept down the hall, barefoot, and pressed myself against the wall near the doorway. I peek through a crack in the door, seeing a well-built giant of an older man who looks remarkably similar to him, speaking to my mother in a low, gruff tone.
"I'm not treating her like a project, Inko, she's my grand-daughter. I'm here because I want to help, isn't that why you called me?"
I watch mum sigh, placing her head in her shaking hands.
"Are you here to help or are you here to squash your guilt?" She mutters in response. His face hardens for just a moment before softening, his fingers clenching around the mug of coffee. "That's not fair, Inko. I couldn't help him, and I've come to terms with that a long time ago," He sighs, taking a sip from the mug. "I just...I can teach her better than anyone, how to control it, how to use it for good rather than..." He pauses, looking down at the wooden table. "She has to know that she isn't just dangerous, that she can protect better than destroy. These moments in her early development are vital to her learning. If she stays in this environment, she'll be villainised, her growth will be stunted and her mental state will deteriorate. I've learned from my past mistakes, I can't fail my grand-daughter too. Please, Inko, trust me," He's beginning to look less like a jaded giant and more like a...sad old man.
I didn't wait to hear more.
I padded back down the hallway and slipped into Izuku's room. He was curled up beneath his All Might blanket, snoring softly, cheeks puffing out with every breath. I crawled in beside him, quiet as I could, and pressed my forehead to his shoulder. He shifted in his sleep, one arm flopping over me in that clumsy way of his.
I closed my eyes, but the tears still came. Silent, hot. The kind that didn't need sound to hurt.
I didn't want to go.
But I knew I had to.
The morning came too fast.
Mum and Kenji sat me down at the kitchen table. The sunlight looked out of place—too bright for the heaviness in the room. I could barely look at Mum's eyes, all puffy and rimmed red. She reached across the table and took my hand.
"Kasai..." Her voice cracked. "I know this isn't what you wanted. I didn't want it either. But... I think it's what you need."
Kenji sat across from me, mug in hand again. His eyes were softer than last night, like maybe they were hiding their own kind of grief. He didn't look like a stranger anymore. I looked between the two adults. Then at Izuku, who stood in the corner, his fists clenched, face crumpling like paper with tears already decorating the chub of his cheeks.
"I want to learn," I said, voice small but steady. "I want to protect you. All of you. I need to learn how to do that."
Izuku sobbed. Not loud. Just a small, broken sound like his heart was cracking right in half.
"Y-you promised we'd be together forever! Me, you, and Kacchan are 'pposed to go to UA together like All Might!"
I jumped from my seat and wrapped my arms around him, and he hugged me back like he never wanted to let go. Mum joined us a second later, arms pulling both of us in tight. She smelled like home. Like tears and warm laundry and vanilla shampoo.
"I'll come back," I whispered against her chest. "Stronger."
"I know you will, sweetheart," she breathed. "I know."