Kazuto Mikage awoke to darkness, though he knew he had been awake before. The air was thick, clinging to his lungs like a wet shroud, and the smell of rust and rot burned at the back of his throat. He tried to move. Pain exploded along his limbs, a dull, constant throb, as if his body had forgotten how to obey him. Chains clinked somewhere in the shadows.
He opened his eyes. Nothing but blackness. Or was it black? Shapes twisted just beyond sight, moving with intent he could feel but not comprehend. His own heartbeat thudded in his ears, irregular, anxious.
A whisper curled through the darkness.
"Welcome back…"
Kazuto froze. He did not know whose voice it was, though it felt intimate, familiar. He tried to speak. No sound came.
Then he saw it — a faint glimmer ahead. A door, its edges warped, breathing as if it were alive. He moved toward it, dragging his limbs like lead, each step a fight against himself.
When he reached the door, his hands — pale, trembling, and somehow unfamiliar — touched the surface. Pain surged through him, white-hot and intoxicating. Memories flickered in flashes: a lab, glass vials shattering, a woman screaming his name, hands pulling levers, fire, and… cells. Millions of cells, writhing, alive. Something had gone wrong.
The door creaked open. Beyond it lay a corridor — narrow, endless, its walls pulsating subtly, like the veins of some massive, sleeping creature. He stepped in. The chains clinked again, closer this time. Shadows stretched toward him. He ran.
And then, suddenly, everything stopped.
A whisper again. "Die, and come back. Learn, and die again. You belong here."
Kazuto did not understand. Could not remember why. But in that moment, as the darkness swallowed him whole, he realized something horrifying: he would never leave this place. Not alive, not dead.
And somewhere deep inside, the first pulse of the infection — the Cell — awakened.
It coiled in his veins, a spark of power and corruption, and whispered promises he did not want to hear.
---
Kazuto's eyes snapped open again. He was on a cold, stone floor, chains dangling from the walls around him. His body ached as if he had been wrung through a grinder and then reassembled, but he was alive — somehow.
The corridor ahead pulsed faintly, shadows crawling across walls as if the darkness itself were breathing. A low hum resonated in the air, vibrating in his teeth and bones. Kazuto rose slowly, testing his limbs. They moved, though stiffly, as though relearning their own weight.
He remembered the whispers — the promise of dying and returning, again and again. And he remembered the pain.
Something scuttled in the shadows. A rat? No… too big, twisted. Its eyes glowed faintly red, teeth sharp and dripping with something black.
Kazuto's instincts screamed. He yanked a piece of jagged stone from the floor, gripping it like a blade. The creature lunged, and he swung. The stone caught it across the skull. It squealed, but it didn't die. It recoiled, circling, stalking him.
He ran.
The corridor twisted. Walls seemed to stretch and contract, narrowing then widening without reason. He barely noticed the chains dangling just above him — a single misstep and they would catch him, bite into his skin. His chest burned. The pain was not just from running; it was something else, something inside him.
A warmth spread through his veins. It started in his fingertips, like liquid fire, and surged upward. His senses sharpened. He felt the rat before he saw it, its position, its intent. He ducked just as it lunged, swinging the stone with precise accuracy. This time, the creature screamed and froze — then dissolved into a puddle of writhing cells, black and red, crawling over the floor like liquid life.
Kazuto stumbled back, breathing hard. He touched the remnants of the creature. The cells pulsed faintly under his fingers. The warmth surged again, stronger. He gasped, staggering — he felt his body adapting, reacting, changing.
First mutation… he realized without understanding how, he could sense movement, intent, even the edges of danger in ways his normal body never could.
But before he could dwell on it, a whisper floated through the air:
"Learn… or die."
Shadows shifted. The walls themselves seemed to twitch, closing in, guiding him forward. A doorway appeared ahead, glowing faintly. Beyond it lay a stairwell descending into blackness. He didn't hesitate. He ran.
The stairwell led him to a wide hall, broken and decayed, littered with debris. Something large moved in the distance — slow, deliberate, its steps shaking the floor. He froze.
It was humanoid. Massive. Its body was fused with chains and rusted metal. The first real challenge.
Kazuto's hands tingled. The mutation flared again, his muscles responding faster, his reflexes sharper. He gripped a broken pipe, ready. He didn't know if he could survive — but he had survived once, and he would survive again.
The creature roared.
Kazuto's pulse raced as it advanced. Its movements were slow, deliberate, but every step made the ground tremble. Instinctively, he sidestepped, narrowly avoiding a heavy metal fist swinging for his head. The warmth in his veins surged again, tingling, sharpening his reactions.
He jabbed with the pipe, striking metal. Sparks flew. The creature roared, swinging again, forcing him to leap backward. Pain exploded in his shoulder — his muscles strained beyond recognition, but the new sensation, the heightened reflex, helped him roll away just in time.
Then, as he slid under a low-hanging chain, he saw it. A faint glow from the corner of the hall. A figure, cloaked in shadows, stood where the wall met the ceiling. Watching. Waiting.
"Interesting," the figure whispered, voice soft but piercing. "Alive… adapting… but fragile."
Kazuto froze. The figure did not move, yet he felt its gaze like a physical weight pressing against his chest.
Who… or what is that?
Before he could react, the chain-fused creature lunged. Kazuto's body moved before his mind did. The mutation flared again. He sidestepped, twisted, grabbed a fallen iron rod, and swung with every ounce of strength. The creature screeched as the rod collided with its head, sending it staggering backward.
It roared, thrashing violently. Kazuto backed toward a crumbling wall. His muscles burned, reflexes screaming for respite, but he could not stop. Not yet.
Then it struck — a heavy, crushing blow that sent him flying across the hall. Pain erupted in every joint, his vision swimming, and darkness crept at the edges of his eyes.
And then — nothing.
---
When Kazuto opened his eyes, he was on the cold stone floor again. The hall, the creature, even the chains — all reset.
Again.
His heart pounded, disbelief clawing at him. His body was intact, but the pain lingered in memory. A new sensation tingled in his veins: control. Not complete, not yet, but awareness of his own mutations — muscles stronger, reflexes faster, senses sharper.
He pushed himself to his feet. The hall stretched before him, broken and decayed, but he felt… different.
"Learn," whispered the shadowy figure again, just beyond reach. "Die, adapt… or remain forever."
Kazuto Mikage clenched his fists. The first loop had ended. But survival was only beginning.
He moved forward, careful, deliberate. Every step was a lesson. Every shadow a threat. The island was alive. He was prey. And maybe, just maybe… he could become something else entirely.