Blood Demon in Demon Slayer - Chapter 1

Chapter 1 — The Price of One Hundred

The beeping had become a kind of music.

Arun had learned to sleep through it months ago — that steady, mechanical rhythm of the heart monitor beside his bed. ‘Beep. Beep. Beep.’ It counted the seconds with indifference, as though his life were nothing more than a metronome someone had forgotten to switch off.

The ceiling of Room 214 was a dirty shade of white. Arun knew every crack in it. Every water stain. There was one that looked like a dog if you tilted your head just slightly to the left, and another near the ventilation grate that resembled the silhouette of a mountain range. He had catalogued them all during the long nights when the pain made sleep impossible.

Twenty-three years old. Blood cancer. Stage four.

The doctors never said it aloud anymore. They didn’t have to. He could read it in the way his mother held his hand too tightly when she visited, or how his father stood by the window with his back turned, pretending to look at something interesting in the hospital parking lot below. There was nothing interesting in that parking lot. There was never anything interesting in that parking lot.

Arun didn’t blame them. Grief did strange things to people.

He reached for the tablet on his bedside table. The motion pulled at the IV in the back of his hand — a familiar, dull sting he had long since stopped acknowledging. The screen lit up, casting pale blue light across his gaunt features, and the pause screen of Demon Slayer appeared.

‘Episode 41 of the Hashira Training Arc.’

He had been rationing it.

That thought almost made him laugh, and the laugh almost became a cough, and he swallowed it down carefully, the way you swallowed anything these days — slowly, deliberately, aware that even laughter had consequences. But the irony was real. He, Arun Mehra, a man who had binged entire seasons in single weekends before his diagnosis, was now ‘rationing’ episodes of an anime because he was afraid of what came after the last one.

The ending.

He knew the ending. He had read the manga two years ago, back before everything went sideways — back when sideways was still a direction he could fall and get back up from. He knew who lived. He knew who died. He knew the sunrise after the final battle, the way the light fell across exhausted, blood-soaked survivors who had earned every ray of it.

But reading it and ‘seeing’ it were different things.

Reading it, you supplied your own music. Your own voice for the characters. Your own timing for the pauses. Seeing it meant animators had poured months of labor into making those moments ‘move’ — the way fire breathed, the way blades caught moonlight, the way tears tracked down faces that had been drawn by human hands who understood what it meant to lose someone.

Arun wanted to see it.

He was afraid he wouldn’t.

He set the tablet down without pressing play, and stared back at the ceiling, at the dog-shaped water stain, and he thought: ‘it’s fine. I read it. I know how it ends. That’s enough.’

It wasn’t enough.

The monitor beeped. Outside the room, someone wheeled a cart down the corridor, wheels squeaking on linoleum. A nurse’s voice, far away, gentle and professional. The ordinary sounds of a building where people came to die in incrementally kinder ways than they might have otherwise.

His eyes grew heavy.

The last thing he thought, before sleep pulled him under for the final time, was that he wished he could have seen the sunrise.

—

Then he was standing in blood.

Not the clinical, contained kind he had become familiar with — the careful red of IV lines and bandage changes and cautious lab samples. This was ‘blood’. Oceans of it. A field of it, dark and still and impossible, pooled across a ground he couldn’t see beneath its surface. It reached his ankles. The warmth of it was the most horrifying thing — it wasn’t cold like he might have expected. It was warm. Almost body temperature. As though it had only just stopped belonging to someone.

Arun looked down at himself.

He didn’t recognise the hands.

That was the first coherent thought that broke through the shock — not ‘where am I’, not ‘what is this’, but the simple, visceral wrongness of looking down and seeing hands that were not his. The fingers were longer than he remembered. The skin was rougher. There was a scar running across the left knuckle that he had never earned.

He raised them slowly, turning them over, staring at the unfamiliar architecture of someone else’s palms.

‘What—’

He became aware of the rest of it gradually, the way you become aware of cold water rising when you’ve been standing still too long. His peripheral vision, which he had been instinctively avoiding, began to demand his attention.

He turned his head.

Bodies. Dozens of them. Arranged around him in every direction, in the sprawl and crumple of sudden, violent death. Men and women and — he looked away before he could catalogue further, his stomach lurching with a violence that had nothing to do with the blood cancer that was supposed to be killing him. Except apparently wasn’t killing him. Because he was standing here, in ‘this’, breathing air that tasted like iron and something older and stranger beneath it.

Ninety-nine people.

He didn’t know how he knew that number. He just did, the same way you know the size of a room when you’re standing in it.

Ninety-nine bodies, and him.

“Only one survived from one hundred.”

The voice came from in front of him, and Arun’s head snapped forward with an instinct that surprised him — his body had reacted before his mind had finished processing. Faster than he was used to. The muscles that moved him felt wrong in the way new shoes feel wrong, present and functional but not yet ‘his’.

The man standing before him was… beautiful.

That was the word. Not handsome in any ordinary sense, not attractive the way people were described in casual conversation, but beautiful in the way that things were beautiful when they were also somehow ‘wrong’ — the way certain deep-sea creatures were beautiful, luminous and perfect and operating by rules that had nothing to do with the surface world.

He wore a black suit. He was tall, and still, and his posture carried the particular quality of someone who had never once in their existence felt the need to make themselves smaller for a room. His face was smooth and ageless. His dark hair fell in careful lines across his forehead.

His eyes were red.

Not the irritated red of crying, not the cosmetic red of theatrical contact lenses. ‘Red’. Completely, uniformly red — iris and all, filled with something that caught the dim light like a lamp seen through thin paper, burning quietly from inside.

He was looking at Arun with the mildly curious expression of someone examining an insect that had done something unexpected.

“Pathetic,” the man said. His voice was low, and smooth, and carried the particular ease of someone who never raised it because they had never needed to. “Only one survived from one hundred.”

He paused. Not for effect. He simply waited, the way a man waits who has all the time in the world because time is a concept that has ceased to have dominion over him.

“Be grateful,” he continued. “You are now a demon. With infinite life.”

The words landed without drama. He stated them the way you stated weather. ‘It will rain. You are now immortal.’

Then he turned and began to walk away.

Something — instinct, panic, the fraying edges of a mind that had not yet accepted any of this — made Arun’s new mouth move.

“Wait — who are ‘you’?”

The figure paused. He did not turn fully. Just enough. A quarter-turn, precise as clockwork, the line of his jaw visible, the edge of that inhuman red eye catching Arun in its peripheral arc.

“Your God,” he said.

And walked into the dark.

—

The silence that followed was total.

Then a light appeared.

Not a dramatic light — not heavenly, not ominous. Just a light, clean and pale and sourceless, hovering in Arun’s field of vision with the matter-of-fact presence of a notification window on a phone screen. Which, he realised slowly, was ‘exactly’ what it resembled.

He stared at it.

—

Demon: Lv1 (0/3)
Blood Demon Art: [Locked]

…

HP: 10/10
BP: 10/10

…

STR: 1 | AGI: 1 | VIT: 1 | SEN: 1 | BC: 1

…

Ability: Immortality, Regeneration (Lv1), Biological Absorption (Lv1), Flesh Manipulation (Lv1), Information Sharing (Lv1), Menacing Aura (Lv1)

—

Arun read it. Then he read it again. Then he read it a third time, in the specific way that people re-read things when their brain refuses to process the words as meaningful on the first pass.

He lifted his hand — the unfamiliar hand, with its stranger’s scar — and pinched the back of it.

Pain.

Not sharp, not electric, but real. Grounding. Undeniable.

He pinched it harder.

Still real.

He lowered his arm. He breathed. He looked at the blood around his ankles, at the bodies, at the space where the man in the black suit had been standing. He looked at the floating panel with its clean font and its impossible information, glowing patiently at the edge of his vision.

‘Demon Slayer.’

The thought arrived quietly, but with the force of an earthquake.

‘This is Demon Slayer. That man is — that man was—’

He did not say the name. Something in him flinched back from it, some deep-seated instinct he hadn’t known he possessed throwing up a wall before the word could reach his tongue. Because he remembered. He remembered very clearly, watching episodes in his hospital bed, how Muzan had built a curse into every demon he created — a tripwire buried in their very blood, so that the mere ‘act’ of speaking that name internally or aloud would trigger death at most cruel way possible.

He had read enough to know the mechanics of it.

He didn’t know yet whether it applied to him. He didn’t want to find out the hard way.

‘The man in the black suit’, he thought carefully, deliberately. ‘The one who made me a demon.’

That landed without consequence. Good.

He looked at his hands again.

These were not his hands. Arun’s hands had been thin from months of muscle deterioration, the knuckles prominent, the veins close to the surface. These hands were different. This body was different. He was inside someone else — a young man, he thought, probably close to his own age, who had been brought here along with ninety-nine others and had very nearly not survived.

‘Rai’, he thought, and the name came from somewhere — not his own memory but the body’s, a ghost of identity embedded in the flesh he now inhabited. The name felt like the memory of warmth from a fire that had gone out. Someone had been Rai. Someone had stood in this field, terrified, and fought to survive, and in the end had not quite managed it.

But Arun had.

Or Arun had arrived in the space Rai had left, and something between the two of them had crossed a threshold that a single person alone might not have.

He didn’t know. He might never know. The metaphysics of dying and arriving somewhere else were not things he had been warned to prepare for.

What he knew was this: he was in the world of Demon Slayer. He was a demon. The man who had made him a demon was the most powerful and dangerous being in this entire world. And there was a small floating screen next to his head that had given him a set of starting abilities that, if he understood them correctly, were already enormously interesting.

‘Biological Absorption. Flesh Manipulation.’

He filed those away. They were important. He would think about them properly later, when he wasn’t standing in a field of corpses trying to remember how to breathe.

He pulled up the panel again, mentally reaching for it the way you reached for a touchscreen — and it responded, shifting slightly, waiting.

He read the abilities again. ‘Immortality.’ That one he had expected. Muzan’s demons didn’t die from old age. ‘Regeneration’ — that tracked. ‘Menacing Aura’ — he didn’t know what that meant practically, but it sounded like something he’d be careful with around humans.

‘Information Sharing.’

That one was strange.

He turned it over in his mind. ‘Sharing’ information implied there was something to share it ‘with’, or to share it ‘from’. A network. A connection. The way Muzan communicated with his demons through the blood bond—

The notification appeared without warning, cutting across his thoughts like a blade.

[External control signal detected attempting to access host memory.]

[Signal source identified. Suppression initiated.]

[External control signal has been completely removed.]

Arun went very still.

He read the notification three times.

Then the implications finished assembling themselves, like pieces of a puzzle that had been dropped on the floor and now, suddenly, showed him the full picture.

Muzan had a curse. Muzan had blood control over every demon he created — a leash made of biology, invisible and absolute. He could reach into their minds. He could monitor their thoughts, access their memories, drive them like remote-controlled vehicles if the situation demanded it.

But the system had ‘removed’ that signal.

Completely.

Arun looked at the space where the man in the black suit had disappeared into the dark. He thought about red eyes and a voice that stated immortality the way other people stated weather. He thought about the fact that somewhere out there, the most dangerous creature in this entire world believed he had just created another puppet.

Muzan could contact him. That much was probably still true — the blood connection would remain, the way a phone line remained even after you changed the lock on your door. And Arun could contact Muzan in return, when strategy demanded it. There was a value in appearing controllable. A value in not making the leash obviously absent.

But Muzan could not access his memories.

Could not read his thoughts.

Could not pull the strings.

The warmth of the blood around his ankles was already beginning to feel less horrifying and more simply ‘present’ — a fact of the environment, like the temperature of a room. His body was adjusting. His mind was adjusting. The shock was still there, sitting in his chest like a stone he would have to carry for a while, but it wasn’t preventing function anymore. He was ‘functioning’.

He was in the world of Demon Slayer.

He was a demon. Level one, with abilities that didn’t make complete sense yet but promised to become very interesting.

He had just been freed, without the person who owned him realising it, from the single most dangerous leash in this world.

And somewhere, in a future he had already read the ending of, the Demon Slayer Corps was training. The Hashira were preparing. The final battle was being set in motion by ten thousand small decisions made by people who didn’t know yet that they would be the ones to finally end an era.

Arun looked up at the sky above the field of blood. It was dark. Not the clean dark of a clear night, but a heavy, overcast dark, the kind that pressed down and held the heat close. No stars. No moon. Just the thick, directionless dark of a world that was not his, and hadn’t asked him to arrive.

He exhaled slowly.

‘Okay’, he thought. ‘Okay.’

He had read the ending. He knew who won. He knew the names of the dead and the names of the survivors and the shape of the sunrise that came after. That knowledge was not a comfort — it was a map. And maps, in strange territories, were worth everything.

He took his first deliberate step forward, blood parting around his ankle with a sound like a whisper, and did not look back at the ninety-nine.

He had a world to understand before that sunrise came.