Chapter 1
PoV: Aizawa Shota / Eraser Head
Over the past few years, the highest number of deaths had occurred in an old, abandoned laboratory that operated under the cover of a children’s psychiatric hospital. Unaware parents handed their children over here when their behavior became too “disturbing” for everyone else.
And this place…
It was far too unsettling. Too dark.
We stood in front of the large building—abandoned for many years. The negative energy radiating from it was… indescribable. Rarely did I feel things like this, but unease crept under my skin.
I glanced at my good friend—Yamada Hizashi. I knew he felt it too. Everyone gathered there felt the same.
Along with us were several U.A. students from the school where I taught—Bakugo Katsuki, Todoroki Shoto, Kirishima Eijiro, Kaminari Denki, and Shinso Hitoshi. According to Nezu—the principal—they were suited for this mission. I didn’t doubt that.
“Don’t split up,” I said quietly, a little cold, but calm.
When everyone was ready, we moved inside. The moment we crossed the threshold, the stench of rotting, decaying bodies, blood, mold, and worse filled my nostrils. Clearly, I wasn’t the only one who smelled it.
For a while, we walked in silence, occasionally broken by rain dripping onto the floor from the ceiling.
Our footsteps echoed dully off the walls. The building was far too large for the silence it held. Too… aware.
I stopped us with a hand gesture when I felt it for the first time.
Not a sound.
Not movement.
Presence.
It wasn’t aggressive. It wasn’t even hostile.
It was… attentive.
“You feel that?” Todoroki murmured quietly.
Bakugo didn’t answer, but his posture changed. Kirishima stopped smiling. Shinso frowned, as if something was trying to slip into his mind.
This wasn’t a single Quirk.
This was something born from long-term exposure to this place.
We moved on, slower. Eventually, we reached what used to be an observation room. One mirror was cracked; the other was completely black, as if someone had painted it from the inside. Equipment lay scattered—not destroyed, just… abandoned in haste.
And then I saw it.
It was sitting on the floor, back against the wall, where a bed must have once stood. The figure was small—too small for someone who should have survived here this long. Green hair fell over its face, hiding its eyes. Arms wrapped around its knees in a gesture I had seen hundreds of times in children—but never in a place like this.
It didn’t move when we entered.
Didn’t flinch when Bakugo hissed a curse.
It was breathing calmly. Too calmly.
“Is that… a kid?” Kaminari whispered.
“No,” I answered reflexively. I didn’t know why.
The figure slowly raised its head. The movement was smooth, practiced—like it had learned that sudden motions ended badly.
Its eyes were green. Too bright for the darkness.
“You shouldn’t be here,” it said quietly.
The voice was young. And old at the same time.
“What’s your name?” I asked, stepping forward.
The green-haired one stayed silent for a moment, as if checking whether the answer was safe.
“Once…” it began, “…they called me Izuku.”
The name hit me harder than it should have.
Records. Reports.
A child admitted years ago.
Declared missing.
“And now?” I asked.
A shadow crossed its face—something that might have been a smile. Or just muscle movement.
“Now I’m what’s left.”
The air thickened. Not from a Quirk—from instinct. I met its eyes and activated Erasure.
For a fraction of a second… nothing happened.
And then I felt it.
Not resistance.
Not a struggle.
Emptiness.
As if there was no single Quirk to erase. As if the place and it… were one system.
Izuku tilted its head.
“That won’t work,” it said calmly. “I’m not doing anything wrong. I’m just… staying.”
“Staying after what?” Shinso asked quietly.
The green-eyed figure looked at him. And for a moment, I felt like it was looking through him.
“After them,” it replied. “Someone always has to stay.”
The silence that followed those words was heavier than anything we’d seen before.
That’s when I understood.
It wasn’t the place killing people.
It was a child that no longer knew how to live any other way.
And we had just stepped into its only home.
No one moved.
Bakugo was unnaturally quiet for the first time. Todoroki observed Izuku carefully, like he was trying to solve an equation without all the variables. Kirishima instinctively stepped half a pace in front of me—protectively. Kaminari swallowed hard. Shinso… Shinso looked like he was listening to something we couldn’t hear.
“How many of you were here?” I finally asked.
Izuku didn’t answer right away. Instead, it looked up at the ceiling, at the cracks spreading like veins.
“At first… many,” it said quietly. “Then fewer and fewer. They didn’t like it when it got quiet.”
“‘They’?” Todoroki asked.
“Adults,” Izuku replied. “And later, the ones who came after. Curious ones. Lost ones. Lonely ones.”
I didn’t like how it said that. No regret. No satisfaction. Like describing the weather.
“Did you do something to them?” I asked bluntly.
Izuku looked genuinely surprised.
“No,” it denied. “I just… stayed. And they stayed inside me.”
Shinso flinched.
“Aizawa-sensei…” he said softly. “There are too many voices. But none of them are his.”
That was enough.
I stepped forward slowly, showing open hands.
“Izuku. Come with us. This place is dangerous.”
Izuku let out a soft laugh. Short. Joyless.
“Dangerous?” it repeated. “Outside is louder. Outside, people disappear faster.”
“They disappear here too,” Bakugo growled, stepping forward.
Izuku reacted instantly.
Not with movement.
Not with an attack.
The air thickened so much everyone felt it. Kaminari groaned and grabbed his head. Kirishima clenched his teeth. Todoroki froze.
Izuku raised its gaze to Bakugo.
“Please,” it said calmly. “Don’t shout. He doesn’t like it.”
“Step back,” I ordered sharply.
Izuku looked at me with something that resembled guilt.
“I don’t want you to hurt,” it said. “But you’re… full. That’s hard.”
“Full of what?” I asked.
“Of yourselves.”
The answer had no right to sound that logical.
I looked at the students—their faces, the sweat, the tension, the fear. I understood then: every question, every shout, every act of aggression fed this place.
“We’re pulling out,” I said firmly. “Slowly. No sudden movements.”
“And him?” Kirishima asked.
I looked at Izuku again.
It stood there. A child that was no longer a child. A being that wasn’t a monster—but also not human in any way we understood.
“He…” I began.
Izuku tilted its head.
“I can’t leave,” it said quietly. “If I do… they’ll come with me. And you won’t be able to carry that weight.”
And for the first time, I thought something no hero ever should.
Maybe the safest place for the world…
is this cursed laboratory.
PoV: Midoriya Izuku / Object I-0
Silence was the first thing I felt when they entered.
Not footsteps.
Not the smell of rain.
Not their fear.
It was… presence. Not physical presence, but what they brought with them—their emotions.
They shouldn’t have been here.
Each of them carried the weight of lives they wanted to protect, and something they couldn’t understand.
Their fear, their anger, their responsibility—everything filled the air. And with every wave, I felt how their very existence became sustenance for me, for this place.
I didn’t feel joy.
I didn’t feel triumph.
I felt logic. Cold and simple.
They came… and they were full.
Full of life they would never understand again after leaving.
“You shouldn’t be here,” I said quietly.
I didn’t shout. I didn’t need to. My words were silence—calming and warning at once.
Bakugo was the first to sense something was wrong. His anger burned, trying to tear free. Todoroki held calm like a shield, but I felt the tension beneath. Kirishima wanted to protect. Kaminari trembled. Shinso… Shinso looked through me, not at me.
I wasn’t angry.
I wasn’t sad.
I was disappointed.
Why?
Because they were breaking rules that existed as protection. Not for me. For them. For the world outside.
And yet… I couldn’t be angry.
Because I knew that if they didn’t retreat—if they didn’t leave this place alone—they would be consumed. Not physically, but mentally.
Their emotions, fears, self-worth… would become part of me and this place.
I wanted them to understand.
But they couldn’t. Not now. Not while they were still full.
So I did something I had never done before.
I didn’t move.
I didn’t raise my hand.
I didn’t attack.
I didn’t forbid.
I simply… let them feel what would happen.
Their hearts raced. Panic set in. They tried to leave.
I felt their fear flow into me—but I didn’t stop it.
I didn’t want to.
Because I knew one thing: they weren’t ready yet.
And neither was I.
“Next time,” I whispered—to myself more than to them—“there won’t be a warning.”
And then I felt something strange.
Not anger.
Not sorrow.
Peace.
Cold peace—the certainty that I would endure.
They broke the rule.
But I didn’t break myself.
And in the silence, in the emptiness, in their fading breaths… I knew this was only the beginning.
Author’s note (translated):
A short one-shot about Experiment Deku.
A little gift from me to you because it’s my birthday and all that :3
I hope you like it. I’m planning to make a kind of “series” with stories focused on Experiment Deku.
I hope this is your kind of thing ;3
