"You son of a bitch!"
"Why did you give me this?!"
"Wait—where even am I? Is this still Earth?"
Before Yasui Ryosuke could react, a torrent of foreign memories crashed into his brain, twisting his thoughts into chaos.
During the Meiji era, rumors said that demons roamed the night, devouring humans.
Among the common folk, there existed the Demon Slayer Corps—warriors who hunted these creatures to protect humanity.
This is... wait a damn minute... the world of Demon Slayer?!
Ryosuke cried, yelled, and—
No, honestly, he was devastated.
Dude, I haven't even used up all those tens of thousands of Primogems I saved!
Who's going to protect Konoha Village now?!
Liu Tao didn't even get to wear the heirloom outfit yet!
And I still haven't deleted the terabytes of "study materials" on my computer!
My phone's browser history, the shady apps, the "Agent" and "Beauty World" games—none of it's been wiped!
What if Uncle Hat finds my phone?!
"My lifelong wisdom!"
Ryosuke threw back his head and howled.
He was a decent guy, really—an upstanding young man, a model citizen who helped old ladies cross the street. How the hell did he end up drafted into this nightmare after just one night's sleep?!
Turns out, staying up late can kill you.
Guess dying in your chair is the newest method of time travel.
Good news: Yasui Ryosuke had read the original Demon Slayer manga thoroughly.
Bad news: he was dying.
A stabbing pain shot through his chest. His body convulsed violently, and blood spilled from his mouth.
The original owner of this body had been a sickly man already on the brink of death. His parents had been eaten by demons, and he'd been rescued by a one-legged old man with a grim face and a cane.
"You're already in such a terrible state… Brother Tong, stop pretending!" Ryosuke groaned in agony.
A crackling sound filled his mind.
[Evil Demon Extermination System Activated.]
[Host can extend lifespan by slaying demons to cure incurable diseases, and can also consume lifespan to learn breathing techniques and sword skills.]
Ryosuke's lips twitched. "...Chief, how long can I live?"
[Congenital liver failure. Estimated lifespan: one year. Haha~]
"Fuck your sister!"
Ryosuke exploded with rage.
You've got to be kidding me.
This weak, dying body is supposed to kill demons?! He didn't even have a Nichirin Blade!
His lifespan points were literally his life! What kind of scam system makes its host gamble with their existence?
Ryosuke shouted, "How the hell am I supposed to slay demons like this? By guilt-tripping them into suicide?!"
[Calm down, Host. It's only your liver. You can still strengthen your body through training and breathing techniques to slow the damage.]
Grinding his teeth, Ryosuke yelled, "You bastard system! Which company made you? I'm filing a complaint!"
The electric hum in his head subsided. The system seemed to freeze.
It took Ryosuke nearly an hour to accept the truth.
What else could he do but train and fight?
If he didn't slay demons—he'd really die for real this time.
A deliberate cough sounded from the doorway, cutting through Ryosuke's frustration.
He looked up.
An elderly man stood there—short but composed, his aura calm yet fierce. His hair and beard were white, his face lined and stern.
A long scar ran beneath his left eye, and his missing right leg had been replaced by a wooden prosthetic, supported by a crutch.
Kuwajima Jigoro.
The former Thunder Hashira and trainer of the Demon Slayer Corps.
The mentor of Zenitsu Agatsuma and Kaigaku.
Jigoro's expression softened slightly, though his voice carried authority.
"You're a tough one."
"Thank you for saving my life, Master," Ryosuke said, bowing deeply.
Ryosuke stood up and bowed, but his body was weak, and his movements were awkward.
Jigoro approached with his cane, his gaze slicing over Ryosuke like a blade.
"Your body is like a piece of rotten wood, eaten through by insects. A light breeze could knock you over. You're even weaker than an old man like me. You have congenital liver depletion and are deficient in both qi and blood. It's a miracle you've lived this long."
Ryosuke Yasui: "…"
That really hurts, bro!
Was that supposed to be encouragement?
"Was it something you were born with?" Kuwajima asked.
Jigoro frowned. "The doctors of the Demon Slayer Corps can help you recover a little—perhaps buy you some more time."
Upon hearing this, Yasui Ryosuke smiled bitterly to himself.
According to the original owner's memories, this should be the late Meiji period—about ten years before the main story's timeline.
Shinobu and Kanae were still just little girls. The Butterfly Mansion hadn't even been built yet!
Treatment? Treatment my ass!
With the medical technology of this era, how could congenital organ failure possibly be cured?
That's like a toad chasing a frog—you're both ugly, so what's the point?
As for becoming a demon…
Forget it. That scumbag Muzan doesn't pay wages, doesn't offer benefits, and "lays off" subordinates whenever he feels like it. Modern black-hearted capitalists would call him too kind by comparison.
Even if Ryosuke didn't want anything else, he at least wanted to stay beautiful when cross-dressing!
But Muzan only needs to peek into Ryosuke's memories to find the Blue Spider Lily.
And once he achieves that goal, Ryosuke would be crushed into dust without hesitation.
I'm not even scared of sunlight burning me into a JoJo-tier creature anymore—so why would I join you demons?!
The demon route is completely out of the question.
Right now, the situation is simple: if Ryosuke Yasui doesn't kill demons, he'll die. He'll be cremated within a year!
The only way to survive is by relying on the system's life-saving function.
A fierce will to live—and an overwhelming sense of crisis—burned away all hesitation and self-pity.
Seeing the changing expressions on Ryosuke's face, Jigoro assumed he had fallen into despair and was about to offer him some comforting words.
But before he could speak, Ryosuke Yasui acted.
He straightened his back, then bowed ninety degrees toward Kuwajirō.
"Coach! I want to play basketball—wait, no!"
After realizing he'd tuned into the wrong channel, Ryosuke quickly corrected himself.
"Senior! I wish to slay demons! Please teach me!"