Chapter 11: Repaying a Debt
When dealing with someone he truly respected, Shinazugawa Sanemi could be surprisingly rational—and even courteous.
He had come to Hayama to visit his mentor, Arasaki Tetsushin. A brief conversation about recent missions, a few words of concern for his teacher's health—once those were done, Sanemi's purpose was fulfilled.
His gaze shifted to the side, landing on Asuka, who was still clearly unwilling to admit defeat—forcing himself upright, leaning on that battered old blade. Sanemi frowned slightly.
"Sensei… what's with that kid?"
"…Sanemi," Arasaki said calmly, "you know about Natural Breathing, don't you?"
Natural Breathing?
Sanemi raised an eyebrow.
So-called Natural Breathing referred to rare individuals with special constitutions—people who, without ever learning formal breathing techniques, instinctively developed methods to strengthen their bodies, sometimes even gaining the ability to fight demons.
The very origin of the Demon Slayer Corps—the Sun Breathing, ancestor of the Five Great Breaths—had come from one such swordsman. His talent was so extraordinary that later generations couldn't replicate it at all, and the technique eventually vanished.
Another example was the current Sound Hashira. Though his style was called Sound Breathing, its foundation wasn't really a breathing technique at all. His true strength lay in his unique "score," derived from shinobi training and supported by special explosives—essentially unrelated to conventional breathing methods.
So the moment Arasaki mentioned Natural Breathing, Sanemi understood.
"You're saying… this kid is one of those?"
Arasaki nodded. "That's right. His name is Asuka. He's… a very special child. I hope you'll get along with him."
"..."
Sanemi didn't answer directly. Instead, he bowed deeply to Arasaki Tetsushin, then smoothly shifted the conversation back to Demon Slayer Corps matters.
From afar, Asuka couldn't hear clearly. All he felt was a dull haze filling his head.
This was the first time since beginning his training that he'd crossed blades with a true practitioner of the Breath of Wind. The violent sword intent Sanemi carried had churned his blood and breath into chaos.
"Be careful," a gentle voice said. "Sanemi's blade has an extremely strong tearing effect. If you don't treat it properly, it can leave hidden injuries."
Rika had appeared again without him noticing, already kneeling down to bandage his wounds.
"…Thank you," Asuka nodded quietly, thanking the woman who had helped him time and again—her true strength still a mystery to him.
The sun gradually dipped toward the west. Sanemi had said all he needed to say. It was time for him to leave.
"Sanemi," Arasaki said softly, "have you… visited Masachika and Suzune's graves?"
"..."
Sanemi bowed deeply.
"Please take care of your health, Tetsushin-sensei."
He glanced once more at Asuka—now properly bandaged, sitting cross-legged beside Rika, quietly calming the turbulence within his body.
Sanemi's mouth twitched.
Then, in a blur, he vanished.
Once the training grounds finally returned to silence, Arasaki Tetsushin walked over at an unhurried pace.
"Asuka. Are you alright?"
The old man's voice sounded above him. Asuka immediately stood up.
"…I'm fine. Thank you—for stepping in."
Arasaki paused, then sighed softly.
"That wasn't really 'help,' Asuka… You still need to learn more from Rika about how to deal with people."
Hearing that Asuka had genuinely thought he'd been saved made the situation feel oddly heavy.
"Sanemi isn't your enemy. He's just… not very good at expressing himself."
"You should get along with him."
"…Yes!"
Asuka answered firmly.
Even if he didn't fully understand yet—
He remembered this moment.
Arasaki examined the bandaged wounds on Asuka's body. Though the bloodstains made him look frightening at first glance, Sanemi had shown restraint. The injuries were only to flesh and skin—no hidden damage, no lasting complications.
He cleared his throat and said solemnly,
"Asuka. The time has come."
Asuka froze.
Arasaki continued, "Two months from now is this year's Final Selection of the Demon Slayer Corps. It will be held at Mount Fujikasane."
"Under normal circumstances, I might have wanted to temper you for a while longer—at the very least until you could last an hour against Rika before sending you to the selection. But…"
His gaze shifted to the scarred ground of the back-mountain training field, crisscrossed with old sword marks. A decision settled in his heart.
"You took a serious strike head-on from the Wind Hashira and still stood back up. That alone proves you already possess the qualifications to become a Demon Slayer."
The Demon Slayer Corps…
Asuka listened in silence, his thoughts drifting back two years.
Back then, when he had just barely survived, Arasaki Tetsushin had asked whether he was willing to become part of the Demon Slayer Corps. He had agreed purely out of a desire to survive—to protect himself. Was this the moment to repay that debt?
He raised his head and asked, his expression just as serious,
"Sensei… what exactly is the Demon Slayer Corps? And what do you mean by 'Wind Hashira'?"
The moment those words left his mouth, even Rika—who had remained calm the whole time—froze and stared at Arasaki in disbelief.
Arasaki Tetsushin awkwardly scratched his white hair. Thinking it over carefully… it really was true.
For two whole years, he'd focused entirely on training this boy. Asuka knew he was learning how to kill demons—and nothing else.
"Cough… cough…" Arasaki cleared his throat, pointedly ignoring Rika's wordless stare, and finally began explaining the basics he should have covered long ago.
Demons were monsters of unknown origin, appearing without warning, feeding primarily on humans.
Their physical abilities were extraordinary. Injuries healed rapidly; even severed body parts could remain connected to the main body, regenerating into new limbs.
Some demons possessed terrifying supernatural abilities, posing a grave threat to human survival.
The Demon Slayer Corps existed for one purpose: to deal with demons.
As for the Hashira, they were the strongest swordsmen within the Corps—the pillars that upheld it.
At this point, Arasaki paused, his gaze growing complicated.
The Demon Slayer Corps had existed for centuries.
But this was the Taishō era.
The government was enforcing the Sword Abolishment Edict, and organizations like the Demon Slayer Corps—armed groups openly carrying blades—were not officially recognized.
Demon Slayers fought demons with flesh and blood alone, while also remaining wary of restrictions from human society.
"Humans aren't demons," Arasaki said quietly. "Lose an arm or a leg, and it won't grow back. Suffer a fatal wound, and you die. It's a profession taken purely for the sake of protection—one that's dangerous, thankless, and unforgiving."
"Do you understand, Asuka?"
"Have you prepared yourself for that kind of resolve?"
Arasaki watched Asuka's calm face, unable to read the boy's thoughts.
He had already decided—if Asuka didn't wish to become a Demon Slayer, he would keep him here at Hayama, raising him into a cultivator even stronger than himself.
Rika looked at Asuka as well, waiting to hear the decision of this disciple who had trained so relentlessly.
"…If I become a Demon Slayer," Asuka asked calmly, "would that count as repaying your kindness?"
For a moment, Arasaki frowned.
Asuka met his gaze without avoidance. "I only want the strength to survive—to become stronger than anyone else, so I won't be trampled again. I've lived well here at Hayama. I'm deeply grateful for your shelter and your teachings."
"If repaying that kindness means joining the Demon Slayer Corps and killing demons, I won't refuse."
This boy…
Arasaki clenched his remaining right hand, his eyes deep and unreadable.
They stared at each other for a long time. Then, as a gentle breeze passed, Arasaki finally broke the silence with a heavy sigh.
He stepped forward and rubbed Asuka's messy hair.
For the first time, the man who always wore a stern, unyielding expression revealed a look of warmth—and concern.
"Asuka… you're an incredible child. And you've worked harder than anyone."
"Make it through Final Selection."
"Come back alive."
"That's our promise."