The punching bag swung wildly, cracking against the ceiling beam with a loud thud.
Kaito pulled back, chest heaving. His knuckles were bloodied through the wraps, skin split where new bone was hardening underneath. He hadn't stopped training since the shrine incident. Every bruise, every tear, every ache in his body fed the evolution inside him.
> "Pain isn't weakness anymore," he reminded himself. "It's progress."
He glanced at the mirror.
The mark had grown again. What started as a small spiral on his palm now branched across his forearm like jagged lightning, pulsing with a subtle, inner heat. It wasn't glowing now, but it looked… awake.
> "No one else can know just how far this goes."
Because the truth was terrifying.
Each time he hurt himself intentionally, the process adapted. Faster healing. Denser bones. Neural reactions improving by milliseconds. But recently… his dreams had changed.
> Something was watching.
From inside.
---
That Morning – School Courtyard
Momo Ayase slammed her juice box down on the table. "You're gonna die at this rate."
Kaito sat across from her under the tree near the gym, quietly eating his rice ball, ignoring the dull throb in his ribs.
> "You think I don't notice?" Momo said. "Your hands are jacked up again. You've got bags under your eyes. And you flinched when I bumped your shoulder."
He looked up. "Training."
> "No one trains that hard unless they're running from something," she snapped. "You think getting strong overnight makes you cool? Makes you some shonen hero?"
He stayed silent.
Momo leaned forward, lowering her voice. "There's something weird around you lately. Your energy's off. Not spirit… not yokai… Something else."
He met her gaze and whispered, "I'm not human anymore. Not completely."
Her eyes widened — but not in fear.
Something softer flickered in them.
> "So?" she said. "Who is, these days?"
---
Meanwhile – Seiko's Apartment
Seiko Ayase dragged her long cigarette across the ashtray and frowned.
> "Kid's pushing himself too fast," she muttered.
She sat cross-legged in front of her shrine, incense burning in lazy spirals. In her hand was a photo — a snapshot of the charm she'd given Kaito. The moment it burned at the shrine, the spiritual energy had recoiled — violently.
She'd seen war gods flinch less.
> "That power in him… it's reactive. Dangerous. But not evil. At least, not yet."
She drew a line of salt across the floor, lips whispering an old mantra. The paper she placed in the center caught fire — not from the match, but from her aura.
A shadow flickered on the wall.
> "Yeah," she muttered. "Something's watching him. And it's not from this world."
---
That Night – Kaito's Room
The pain came suddenly this time — not from training, not from battle, but from within.
Kaito doubled over, coughing violently. Blood splattered across the floor. His vision went white. Something inside his spine twisted — like a cord being pulled taut.
> "Ngh—!"
His body dropped to the ground, convulsing. Muscles spasmed, bones shifted slightly. For ten full seconds, he couldn't breathe.
> "System reacting to internal instability."
"Initiating emergency adaptation..."
The mark on his body pulsed wildly, spreading toward his back. His ribs cracked—then reformed, reinforcing themselves with a lattice of bone just under the skin. His lungs burned, then cooled.
> New Trait Acquired: Oxygen Optimization (Level 1)
New Trait Acquired: Skeletal Reinforcement (Level 1)
Minor Mutation Stabilized
Kaito lay there, trembling.
> "I didn't get hurt this time," he muttered. "The evolution... triggered on its own?"
That was new.
That was dangerous.
---
The Next Morning – School Infirmary
"Are you sure you're not being abused?" Rin asked, her voice steady but worried.
Kaito blinked, sitting up on the infirmary bed. "What?"
Rin sat beside him, arms folded, long black bangs hiding half her expression. "You passed out in gym. You've got bruises in weird places. Internal damage. I can sense it."
She stared at him.
> "You're breaking yourself. And something in you is fixing it. I can feel the energy shifting inside your body every time I touch your aura."
Kaito hesitated.
Then whispered, "It's an ability. When I get hurt, my body… evolves. Adapts."
Rin blinked once, then nodded slowly. "I believe you."
He stared. "Just like that?"
> "I saw a ghost crawl out of my TV last year. And I talk to my dead cat every Thursday. You're not even in my top five weirdest experiences."
She looked at him — really looked.
> "But I've seen powers consume people, Kaito. Powers that start out as tools… and end up being cages. Just promise me you'll tell someone before it's too late."
> "I will," he lied.
---
After School – Empty Lot Behind the Gym
Kaito stood facing a stack of broken concrete blocks. He breathed slowly, the echo of his recent transformation still humming under his skin.
> "If I don't keep testing the edge… I'll never be ready for what's coming."
He wrapped his fists tight, braced himself — and drove his knuckles into the first block.
Pain flared.
Bone splintered.
Then the mark glowed — and his body began repairing mid-impact, muscles adapting for high-impact recoil. He slammed again. And again. The blocks shattered by the fourth strike.
His knuckles healed before the blood even dried.
He was getting faster.
Stronger.
More dangerous.
But with each adaptation… the voice in his dreams grew louder.
---
Dream Sequence – Unknown Place
He floated in an endless space of black water.
And across from him, a version of himself stared back — older, scarred, eyes glowing with the same spiral mark burned across both irises.
> "You're evolving well," the reflection said.
> "Who are you?" Kaito asked.
The reflection smiled.
> "A possible future. One where you survive long enough to become the apex."
> "Apex of what?"
The reflection tilted its head. "Everything."
Kaito woke up in a cold sweat, gasping.
The mark on his chest had grown again.
---
End Scene – Seiko's Perspective
Seiko Ayase placed a ward over Kaito's front door when no one was looking.
"Poor dumb kid doesn't realize," she whispered, "half the monsters out there are gonna want that body of his. To devour it… or wear it."
She lit another cigarette and muttered:
> "And the worst ones... are already inside."