When facing someone he respected, Sanemi Shinazugawa was still quite rational and well-spoken.
He had come here in the first place to visit Tetsushin Arisaki. Being able to chat briefly about recent work and show concern for his teacher's health was enough to accomplish his purpose.
Sanemi glanced at Asuka, who was still unwilling to admit defeat, struggling to stand while leaning on that broken blade. His brow furrowed slightly.
"Teacher, what's the deal with that kid?"
"...Sanemi, you know about Natural Breathing, right?"
Natural Breathing? Sanemi raised an eyebrow.
So-called Natural Breathing referred to certain people with special constitutions who, without ever learning formal breathing techniques, independently developed abilities that could strengthen the body and even allow them to fight demons.
The origin of the Demon Slayer Corps itself, the ancestor of the Five Major Breathing Styles—Sun Breathing—had come from a powerful swordsman's natural ability. Because of this, later generations were completely unable to learn it, and it gradually became lost.
Another example was the Sound Hashira in the same corps. Although his Sound Breathing was said to be a derivative style, at its core it relied on specially made explosives as support. The true essence of his power, the "Score," originated from his own shinobi training methods and was essentially unrelated to breathing techniques.
So when Arisaki mentioned Natural Breathing, Sanemi immediately understood what he meant.
"You're saying this kid is...?"
Tetsushin Arisaki nodded. "That's right... Sanemi. His name is Asuka. He's a very special child. You should get along well with him."
"..."
Sanemi did not respond directly. Instead, he respectfully bowed deeply to Tetsushin Arisaki and steered the conversation back to matters concerning the Demon Slayer Corps.
From afar, Asuka couldn't hear clearly. All he felt was his head spinning.
Since beginning his training, this was the first time he had fought directly against true Wind Breathing. The energy and blood within his body were still in turmoil, violently stirred by Sanemi Shinazugawa's terrifying sword aura.
"Be careful. Sanemi's blade has a powerful tearing effect. If you don't handle it properly, it can leave hidden injuries."
Miss Rika appeared again at some point, drifting over as she began to bandage Asuka's wounds.
"Thank you..." Asuka nodded slightly, expressing his gratitude to this female disciple of unknown strength who had consistently helped him.
The sun gradually dipped westward. Sanemi had said everything he needed to say, and it was time for him to leave.
"Sanemi... have you visited Masachika and Suzune's graves?"
"...Please take care of your health, Teacher Arisaki."
Sanemi bowed deeply once more, glanced at Asuka—already bandaged and sitting cross-legged with Rika, calming the turbulence within his body—then twitched the corner of his mouth.
In the blink of an eye, he vanished from the spot.
After the training ground finally returned to calm, Tetsushin Arisaki slowly walked toward the two who were sitting cross-legged.
"Asuka, are you alright?"
Arisaki's voice sounded above Asuka's head. Asuka hurriedly stood up and replied, "...I'm fine. Thank you for stepping in to help."
"This doesn't count as helping, Asuka... You still need to learn more from Rika about how to interact with others..." Hearing Asuka actually think that stopping Sanemi counted as helping him made Arisaki feel a strange sense of discomfort. He could only sigh helplessly.
"Sanemi isn't your enemy. He's just not very good at expressing himself... You two need to get along well."
"...Yes!"
Arisaki examined the already bandaged wounds on Asuka's body. Though he looked bloodied and frightening, that kid Sanemi still had a sense of restraint. The injuries were only superficial; there was no risk of lasting harm.
Clearing his throat, Arisaki said solemnly:
"Asuka, the time has come."
Hearing this, Asuka froze. Arisaki continued, "In two months, the Demon Slayer Corps' selection trial for this year will begin! It will be held at Mount Fujikasane!"
"Normally, I would have wanted to polish you a bit more—at least until you could last an entire hour under Rika's hands before letting you go to the selection. But..."
He glanced at the weathered sword marks covering the back mountain training grounds and made his decision.
"You were able to take a serious strike from the Wind Hashira head-on and still stand. That proves you already possess the ability to become a Demon Slayer."
The Demon Slayer Corps... Asuka listened silently to his teacher's words, his thoughts drifting back two years.
Back then, when Tetsushin Arisaki asked whether he was willing to become part of the Demon Slayer Corps after barely escaping death, he had agreed purely out of a desire to survive. Was it time to repay that debt now?
He lifted his head and asked with an equally serious expression:
"Teacher, what exactly is the Demon Slayer Corps? And what is the Wind Hashira you mentioned?"
At those words, even Rika—who had remained calm the entire time—froze, staring at Tetsushin Arisaki in disbelief.
Arisaki scratched his white hair awkwardly. Thinking about it carefully, it really was true...
For two whole years, he had focused solely on training Asuka. The boy only knew that he was learning how to kill demons and knew nothing else.
"Ahem..." Clearing his throat, Arisaki ignored Rika's speechless gaze and began explaining the fundamental knowledge he should have mentioned long ago.
Demons were monsters of unknown origin, appearing at unknown times and places, feeding primarily on humans.
They possessed extremely high physical abilities. Even after being injured, they would heal rapidly. Severed parts could remain connected to the main body and even regrow into new limbs.
Some were even capable of wielding powerful and terrifying supernatural abilities, posing a severe threat to human survival.
The Demon Slayer Corps existed solely to deal with these beings known as demons.
As for the Wind Hashira, that title referred to one of the strongest swordsmen within the Demon Slayer Corps.
At this point, Tetsushin Arisaki paused, his gaze growing complicated.
Although the Demon Slayer Corps had existed for hundreds of years, dating back generations, they now lived in the Taisho era.
The current government was enforcing a Sword Abolishment Edict. Organizations like the Demon Slayer Corps, which carried blades to fight demons, were not officially recognized.
Thus, Demon Slayers not only had to fight demons with their own flesh and blood but also remain wary of restrictions imposed by human society.
"Humans aren't demons. If our limbs are severed, they don't grow back. If we're seriously injured, we die... It's a profession that exists purely to protect others, exhausting and thankless."
"Do you understand now, Asuka? Are you prepared for that?"
Tetsushin Arisaki looked at Asuka's calm expression, unsure of what the child was thinking.
He had already made plans. If Asuka, given his personality, did not wish to become a Demon Slayer, he would keep him in Hayama and have him grow into a instractor even stronger than himself.
Rika also turned her gaze toward Asuka, wanting to hear what decision this tirelessly training disciple would make.
"...Would becoming a Demon Slayer count as repaying your kindness?"
"...What?"
Arisaki frowned slightly.
Asuka met his gaze calmly, without avoiding it. "I just want the power to survive, to gain strength greater than anyone else, so I won't be bullied again. I've lived very well in Hayama. I'm deeply grateful for your shelter and guidance."
"If this debt must be repaid by joining the Demon Slayer Corps and killing demons, I won't refuse."
This kid...
Tetsushin Arisaki clenched his only remaining right hand, his eyes deep and unreadable.
The two stared at each other for a long time. Finally, a gentle breeze passed, and Arisaki broke the silence with a heavy sigh.
He walked slowly up to Asuka and ruffled the boy's messy, thick hair.
The always stern and severe Tetsushin Arisaki revealed, for the first time, a gentle and worried expression.
"Asuka... you're an incredible, hardworking child..."
"Make sure you pass the Final Selection and come back alive..."
"Okay! It's a promise."