Ryousuke didn't hesitate. The moment the words left his mouth, he stayed pinned in a deep bow, his forehead nearly touching the floor.
"Oh? And what is your name?"
"Ryousuke. Yasui Ryousuke."
Jigoro's expression hardened. "Slay demons? With a body like that?" His voice was gravelly, laced with a blunt, cruel skepticism. "A breeze knocks you over. You cough blood after a few steps. Can you even lift a blade? Can you swing it? Training in the Breathing Styles is an agony that grinds your bones to dust only to reshape them."
The old man leaned on his cane, his shadow looming over the boy. "That broken shell of yours will give out long before you ever lay eyes on a demon."
The Demon Slayer Corps lived on the edge of death. Cultivators like Jigoro were responsible for feeding fresh blood into the ranks to ensure humanity's survival. Time was their most precious resource. No one wasted it on a dying boy with less than a year to live.
Ryousuke knew the truth in those words. His body was a lead weight.
But he looked up. His eyes were bloodshot from pain, yet deep within them, a fire burned—a frantic, obsessive hunger for life.
"Master! My family was slaughtered by those things! I can do this!" Ryousuke's voice cracked into a roar. "If I can't hold a sword, I'll use my teeth! If I can't swing a blade, I'll throw my body at them!"
"As long as I can kill them... as long as I have the power to strike back, I'll endure anything! If my bones break, I'll set them and keep going! If I run out of blood, I'll swallow it and stay in the fight! Master, please! Just give me one chance!"
Silence fell over the room, broken only by Ryousuke's ragged, wheezing breaths. This was his only path.
The scrutiny in Jigoro's eyes slowly faded. He looked at the frail teenager—a boy who looked like he might expire at any second—and saw a flicker of something he hadn't seen in years. A desperation that transcended logic.
Finally, Jigoro exhaled. "Follow me."
The old man had a soft heart, after all.
Ryousuke followed him out, squinting as they stepped into the harsh sunlight. They crossed a long corridor to the rear of the estate, opening up to a wide, flat clearing surrounded by a lush forest of peach trees.
This was Peach Mountain. The ground was packed hard from years of footwork, lined with wooden posts, stone weights, and weapon racks.
Two figures were already mid-drill.
A boy, around fourteen, moved with the agility of a mountain monkey. Beside him was a younger girl, her hair tied in a simple bun, her movements fluid and focused.
"Shota! Rika!" Jigoro called out.
"Gramps!"
The two stopped mid-swing and hurried over.
"Gramps!" Shota grinned, his bright eyes immediately landing on Ryousuke. "Who's this?"
"Yasui Ryousuke," the newcomer wheezed, his voice like sandpaper.
"Kiritani Shota!" the boy chirped, pointing to the girl. "And this is my sister, Rika."
"H-hello..." Rika offered a shy bow, her voice soft.
Ryousuke nodded. He searched his memory, but these two weren't in the original story. That meant one thing: they likely wouldn't survive the Final Selection at Fujikasane Mountain. Without a certain "Head-on" protagonist to save the day, the Hand Demon was a death sentence for most candidates.
"Ryousuke isn't well," Jigoro said, his tone turning sharp. "But he has decided to walk the path of a Slayer. From today, he trains with you."
The old man's gaze turned cold as he looked at the trio. "Shota! Rika! Basic conditioning. Fifty laps around the grounds. Ryousuke..." He glanced at the boy's trembling knees and pale face. "Twenty laps. Walk them if you have to, but you finish. Now! Move!"
Shota and Rika didn't hesitate, bolting off with effortless, light-footed speed.
Ryousuke took a breath and started. The clearing was at least five hundred meters around. Twenty laps... ten kilometers. He hadn't run that far in his previous life, let alone in this broken body.
Before he finished half a lap, his lungs began to burn. His vision blurred. Sweat—cold, sickly sweat—poured off him. Shota and Rika blurred past him again and again, Rika casting worried glances over her shoulder each time.
Three laps... four...
Every step felt like his heart was going to burst through his ribs. His mind narrowed down to a single thought: Finish. Survive. This is step one.
The sun began to dip toward the horizon. By the time Shota and Rika finished their drills and headed inside for dinner, Ryousuke was still moving.
In the end, he practically crawled across the finish line. He collapsed on his hands and knees, his skin a deathly shade of grey, a racking cough tearing through his chest.
Inside the house, Rika looked at Jigoro. "Gramps, is Ryousuke-san going to be okay?"
Jigoro watched the boy through the door. "He's fine. Eat your dinner."
"But—"
Shota started to speak, then froze. Out in the yard, Ryousuke was dragging himself back up. With legs that shook like leaden pillars, he staggered toward the weapon rack.
"Wait... is he serious?" Shota gasped.
Jigoro said nothing, but a faint, almost imperceptible twitch of a smile touched the corner of his mouth.
Ryousuke gripped a wooden training sword. The weight nearly snapped his wrists. He planted his feet, reaching into his blurred memories to mimic the swings he had seen the siblings doing earlier.
"Hah—!"
He swung. It was clumsy. It was weak. His form was a mess.
But he didn't stop. Lift, swing. Lift, swing.
It was a battle of pure will against failing flesh. Shota and Rika stood frozen, their dinner forgotten, watching the boy in the twilight.
Late that night, the pain was too sharp for sleep.
The door to Ryousuke's room slid open. Jigoro entered, carrying a bowl of medicinal tea and a jar of ointment. The room was dark, lit only by a sliver of moonlight.
Before Ryousuke could speak, Jigoro sat down. He coated his hands in the pungent oil and began to knead the boy's cramped leg muscles.
The pressure was immense, delivered with a rhythmic force that ground the pain deep into the bone even as it forced the muscles to relax.
"Ungh—!" Ryousuke hissed through gritted teeth.
After a few minutes, a strange, penetrating heat began to replace the ache.
When the old man finally stopped, Ryousuke lay limp on the mat, drenched in sweat.
"Drink," Jigoro commanded, holding the bowl to his lips. The tea was obscenely bitter, but Ryousuke forced it down.
"Master..." Ryousuke's voice was a ghost of a sound.
He had lost his parents early in his previous life, drifting through society as a nameless cog. This sudden, rough kindness hit him harder than the training.
"Can I... can I call you Gramps? Like the others?"
There was a long silence.
Jigoro let out a dry cough, sounding annoyed. "Do whatever you want! So noisy!" He snatched the empty bowl and turned to leave.
But as he stepped into the hallway, his face softened into a look of grandfatherly warmth.
Ryousuke watched him go, a flicker of genuine heat blooming in his chest. He pulled the thin blanket over his head, his shoulders shaking slightly in the dark.