"Kid, I recognize your talent. Come be my Son."
Shinazugawa Sanemi stared at Naruto with burning eyes, his voice fervent. "I will personally train you to become the strongest Demon Slayer!"
Given Shinazugawa Sanemi's personality, he would never normally consider training new recruits. Initially, he had planned that if Naruto truly had talent, he would send him to a familiar trainer.
However, the talent Naruto displayed suddenly reminded him of someone—a foolish woman with an astonishing physique and muscle density eight times that of an ordinary person.
If Kyojuro can train a Pillar-level Son, then I, Shinazugawa, definitely can too. And the new recruit I train will surely be stronger than that foolish woman whose chest is bigger than her brain! Shinazugawa Sanemi thought.
Even someone like him, upon seeing a "genius" like Naruto, couldn't help but want to try nurturing him.
"Son? No way!"
Naruto immediately rejected Shinazugawa Sanemi's demand, saying with a look of disgust, "You don't look much older than me. I'm not going to be your Son."
After a month of adjustment, Naruto had adapted to his current body and had begun to think of himself as a fifteen-year-old "adult."
He was no longer a six-year-old child. There was no way he would become someone else's Son!
"…"
Shinazugawa Sanemi's face darkened upon hearing Naruto's words. He then explained irritably, "You damned brat, in the Demon Slayer Corps, 'Son' doesn't mean son. It refers to a Demon Slayer Corps member personally trained by a powerful Pillar like me."
"Oh, so it's a student."
Naruto nodded in realization after hearing Shinazugawa Sanemi's explanation. "In that case, I can accept it."
If possible, Naruto still wanted to be a Ninja, but it seemed there were no Ninja in this world—and this Wind Pillar looked quite strong.
"Hmph!"
Shinazugawa Sanemi was displeased by Naruto's casual response. He said, "You brat, don't show such an indifferent expression. Be a little more excited! I am a Pillar of the Demon Slayer Corps. You should feel proud to be chosen by me as a Son to be trained.
"If someone lacks talent, they cannot bear the identity of a Son!"
"Oh."
Naruto nodded, thought seriously for a moment, then looked up at him and said, "Mr. Shinazugawa, don't look at me like that. I'm just not good at expressing emotions. Actually, I'm super excited right now… Is that explanation okay?"
"You damned brat…"
Shinazugawa flashed in front of Naruto, knocked him heavily on the head, and roared, "Do I look like someone who needs you to fabricate explanations to comfort me?! And that explanation just now was terrible!"
"Ow!"
Naruto clutched his head and cried out in pain, then looked up at Shinazugawa Sanemi and asked seriously, "So, can you teach me how to become stronger now?"
Shinazugawa Sanemi's expression turned serious. He stared at Naruto for a moment, then grinned and said, "Of course I can. But my training is very rigorous. One wrong move, and you might even lose your life—so you need to be mentally prepared.
"And don't say I didn't warn you. Once you join the Demon Slayer Corps, you must be ready to fight those man-eating demons. You could die at any moment.
"If you regret it, you can still back out now."
Though it was advice, paired with Shinazugawa Sanemi's gloomy tone, ferocious expression, and naturally fierce gaze, it sounded more like a threat.
"Mhm. I've been ready for a long time."
Naruto nodded with determined eyes, clenching his fists as he spoke in a deeper voice. "The moment I witnessed demons eating people, I already made up my mind to kill all the demons in this world!
"Even if it costs me my life!"
Naruto believed the mistake he made a month ago could no longer be salvaged, so from now on, he would hunt more demons to make up for it.
"Hahahahaha!~"
Shinazugawa Sanemi burst into laughter upon hearing Naruto's words. He grabbed Naruto by the collar, pulled the Nichirin blade he had stuck into the ground, and suddenly leaped forward, rushing rapidly in one direction.
His speed was so fast that Naruto felt his breathing become difficult.
After an unknown amount of time, Shinazugawa Sanemi stopped in front of an old-looking mansion and casually tossed Naruto aside.
"Haa!~ Haa!~"
Naruto sat on the ground, panting heavily. His heart was pounding wildly, and his entire body trembled uncontrollably.
Once he calmed his breathing, Naruto looked up and saw Shinazugawa Sanemi staring at him with ill intent.
"Kid," he asked, "how did you feel just now?"
During the run, he had deliberately positioned Naruto so his face was directly against the wind, forcing every breath to fill his lungs with violently rushing air.
The fact that Naruto endured for so long proved that his lung capacity far surpassed that of an ordinary person—enough to qualify him to learn Wind Breathing.
"I felt… great," Naruto replied stubbornly. "I can keep going all day!"
Although he had nearly suffocated several times, Naruto's pride would never allow him to admit defeat.
"Hahahahaha!~"
Shinazugawa Sanemi was extremely pleased with Naruto's response and laughed loudly once more. Then his expression turned serious.
"Remember that feeling just now—the sensation of fierce wind rushing into your body through your mouth. Your next training is to maintain normal, steady breathing under those conditions.
"Once you achieve that, you'll be able to learn my Wind Breathing!"
Naruto's displayed talent, as well as his stubborn and unyielding personality, suited Shinazugawa Sanemi perfectly.
"Wind Breathing?"
Naruto's eyes lit up as he asked, "Is that how members of the Demon Slayer Corps train?"
"That's right. Breathing techniques are methods developed by the predecessors of the Demon Slayer Corps, allowing ordinary people to gain the strength needed to fight demons.
"Their main function is to strengthen cardiopulmonary ability, enabling the blood to absorb massive amounts of oxygen in a short time, instantly boosting physical power and achieving endurance beyond human limits."
Shinazugawa Sanemi sat cross-legged on the ground and grinned. "There are many schools of breathing techniques—and my Wind Breathing is the strongest among them!"