Night fell over Mount Momoyama. Inside the small shack, an oil lamp cast a warm glow. Tatsuya, having finished his training, was splayed out on his mat, his muscles aching as if he'd been taken apart and put back together.
"Don't flop around like a fish out of water," came Kuwajima's voice. He held a wooden bowl filled with a pungent herbal ointment. "Relax, you brat."
The old man's rough, warm hand pressed the ointment into the stiffest muscle groups on Tatsuya's back.
"Sss—OW! Gentle, Master! Did you learn this from a blacksmith? My bones are screaming!" Tatsuya hissed.
"Hmph. If I don't use force, how will the fatigue clear? If I don't hammer your frame, how will you carry the violence of Thunder Breathing?" Kuwajima was merciless with his words, but his hands adjusted subtly—sometimes firm to clear the meridians, sometimes gentle to soothe spasms.
Tatsuya yelped at first, but as the heat of the ointment seeped in, he settled into comfortable grunts.
When the massage finished, Kuwajima patted his back. "Done. Go wash up and sleep."
Tatsuya sat up suddenly, his eyes bright. "Wait, Master. Let me return the favor. A disciple should show some filial piety."
Kuwajima blinked. "What are you planning now?"
"Hehe, I've been secretly learning your moves for the last six months!" Tatsuya wagged a finger. "I've specifically studied how to handle that bad back of yours!"
Before Kuwajima could refuse, Tatsuya moved behind him and pressed his hands into the old man's lower back. Kuwajima's body tensed, but as he felt Tatsuya's hands—unrefined but surprisingly accurate in finding the sore spots—he slowly relaxed.
"There... yes, right there. A bit more pressure," Kuwajima directed, eyes closed.
Tatsuya worked carefully, thinking to himself: The old man's injuries are worse than I thought. You'd never know it during training.
After a moment, Tatsuya broke the silence. "Master, I've been on this mountain for nearly a year. Why haven't I seen any other disciples? Are you so amazing that you only have one student?"
Kuwajima was silent for a beat. "What? Feeling lonely?"
"Not really," Tatsuya answered honestly. "Just curious. The Demon Slayer Corps should need all the hands they can get."
"Because we need people, we cannot afford to settle for mediocrity," Kuwajima said gravely. "When I choose a disciple, I prioritize their Heart."
"Heart?"
"Yes." Kuwajima explained. "Thunder Breathing requires an extraordinary physique, as you know. But that isn't enough." He turned his head slightly. "I have seen too many people consumed by the fire of revenge, or lost in the pursuit of power, or those whose hearts are cowardly and hesitate at the crucial moment. Such people, even with talent, I will never take."
He sighed. "Thunder Breathing is the extreme of speed and explosion; it requires unyielding courage and a will as steady as a rock. A corrupt heart with this power is a disaster; a weak heart with it is self-destruction. Quality over quantity. This is my responsibility to the Corps, and to the lives of those who would be my students."
Tatsuya's hands slowed. He remembered why he came here—to protect his village. In his failures, what kept him going was that simple, "not giving up" stubbornness.
"So," Tatsuya blinked, his tone half-joking but serious, "You took me because my heart is... decent? My will is steady?"
Kuwajima snorted, but the slight curve of his mouth softened. "Your technique is stiff and your pressure is uneven... but your placement is accurate."
This silent confirmation warmed Tatsuya's heart. He grinned. "Understood! I'll make sure to take care of your back, Master!"
In that quiet moment, a soft "Gah" came from the window. A crow with jet-black feathers and gentle eyes landed on the sill, a small bamboo tube tied to its leg.
A Kasugai Crow—the intelligent messengers of the Corps. Tatsuya always found them slightly ridiculous.
"Ah, Little Black is back." Tatsuya recognized the crow. It was Kuwajima's messenger, and unlike its master's fiery temper, it was incredibly gentle. (Tatsuya secretly thought his master was terrible at naming things. If it were up to him, he'd name it Thunder Death Shadow or something "cool." He had tried, but Kuwajima had suppressed him.)
Little Black hopped onto Kuwajima's shoulder. The old man untied the tube and read the letter. A genuine smile touched his face.
"It's from Urokodaki," Kuwajima told Tatsuya.
Tatsuya's ears perked up. He knew Urokodaki was the former Water Hashira and his master's friend.
"What does it say, Master? An emergency mission?"
"No," Kuwajima waved the paper. "He's in high spirits. He says his luck at Mount Sagiri has been good. He's found three 'unpolished gems' and taken them all as disciples."
"Three?!" Tatsuya's grip tightened in surprise. "I'm an only child here, but it sounds like a party over there!"
"Mm," Kuwajima nodded. "Urokodaki mentioned them. One boy is calm, resilient, and has the makings of a leader. He thinks highly of him."
"Sounds like a reliable guy," Tatsuya praised.
"And a girl," Kuwajima's eyes showed a flicker of admiration. "Urokodaki says she's agile and incredibly perceptive, with a natural flair for the flowing changes of Water Breathing. A very delicate, sharp child."
"A girl can be that strong?" Tatsuya found the idea of a graceful Water Breathing swordswoman fascinating.
"And finally, another boy," Kuwajima paused. "Urokodaki says he's... quiet. Somber, even. He isn't good with words, but his heart is pure and his focus is terrifying. Once he sets a goal, he has a stubbornness that refuses to back down."
Tatsuya visualized the three—a reliable leader, a clever girl, and a silent, stubborn loner. What an interesting group.
"Urokodaki has a sharp eye for people. If he says this, these children must be extraordinary." Kuwajima tucked the letter away. "By the time the next Final Selection comes around, they should be ready to graduate."
Final Selection!
Tatsuya's heart throbbed. The brutal trial that decided if one could become a formal Demon Slayer.
Kuwajima saw his expression. "When that time comes, you might just have the chance to test your skills at Mount Fujikasane against Urokodaki's three disciples—and the children of other trainers."