Morning sunlight spilled gently over the slopes of Mount Sagiri.
As usual, Chika and Tanjiro rose early. Though both had passed the Final Selection, their chosen Nichirin Steel was still being forged into blades—a process that would take at least half a month before being delivered by the swordsmiths.
That left them with time to train. But endless sword swings no longer yielded much progress, so Chika, arms folded and expression thoughtful, proposed two options:
Option one: go demon hunting.Option two: spar against each other using wooden swords.
Technically, the first option promised faster growth. But finding demons wasn't exactly easy, so they discarded it. Without hesitation, Tanjiro chose the second.
They'd sparred briefly before—short bouts without a clear winner—but even then, Chika had dominated every exchange.
Outside the cabin, the two siblings faced each other across ten meters of dew-damp grass. Both gripped training swords, gazes locked.
Same teacher, same fundamentals—meaning neither could easily overpower the other through technique alone. To win, one had to strike beyond expectation.
Tanjiro inhaled deeply, the rhythm of Total Concentration Breathing surging through him.
"Water Breathing, Tenth Form: Constant Flux!"
A cascade of rippling energy burst from his blade, water spiraling like a living current. His first move—his strongest.
Chika narrowed her eyes. Opening with the Tenth Form? That was bold… or a feint.
In the blink of an eye, Tanjiro's blade slammed into the ground before her, sending a wave of water crashing upward like a tidal surge.
Boom!
The sudden burst of water vapor obscured Chika's vision, but Tanjiro wasn't aiming for her eyes—he was buying a heartbeat of concealment.
Behind the screen of mist, his breathing shifted. The rhythm deepened, pulse quickening—heat replacing flow.
He switched breathing styles?!
A dangerous move. For most Demon Slayers, mastering even one Breathing Style consumed years. Switching between two in combat placed immense strain on the body, but if timed perfectly, it could end a fight instantly.
Few in the Corps had ever managed it. Love Hashira Kanroji Mitsuri herself had once been Flame Hashira Rengoku's tsuguko and inherited fragments of Flame Breathing, only to modify it into her own Love Breathing when she found she couldn't handle the heat.
But Tanjiro was different. So was Chika.
Water Breathing—low cost, perfectly balanced.Hinokami Kagura—the Dance of the Fire God—high consumption, overwhelming power.
Flames burst from Tanjiro's wooden blade as he spun, shouting, "Hinokami Kagura: Dance!"
The fiery arc swept toward Chika with the full intent of victory.
Yet before the blade reached her, Chika moved—lightning-quick, reflexes sharper than thought.
She leapt.
And not merely a step or hop—she soared, clearing the height of his swing in a single effortless bound.
Tanjiro's strike sliced through empty air. A split second later, Chika descended, her counter coming down clean and decisive. The wooden blade stopped just short of his shoulder.
Match over.
Tanjiro blinked, breath caught. "Sister… that jump was insane…"
He replayed the motion in his mind. Even with a full-body windup, he could probably jump to the cabin roof. But she hadn't even crouched—her reaction had been pure instinct.
So this is the power of the demon blood she absorbed…
When Nezuko had first lost control and attacked him years ago, her strength had skyrocketed—feral, unstoppable. His quiet little sister had overpowered him, a trained woodsman, with monstrous ease.
But Chika's power surpassed even that.
Tanjiro stared at his wooden sword, clenching the hilt. I have to get stronger too. If stronger demons appear, I can't just watch—I have to fight beside her.
"Sister," he said at last, eyes determined. "Let's go again after lunch!"
Chika smiled. "Anytime, little brother~."
They trained from dawn until the sun climbed high. Only when Urokodaki came out carrying trays of lunch—his voice like a scolding parent—did they finally stop.
As they turned toward the cabin, they saw him first, then another figure peeking timidly from behind the door.
Nezuko.
Unable to step outside, she leaned out just enough to see them, wary of the sunlight streaming past the eaves.
She didn't yet know that she was an exception among demons—immune to the sun's deadly light. In the future, she would realize it herself; but for now, Chika said nothing. Some truths were better saved for the right moment.
Back inside, Nezuko no longer wore her bamboo muzzle. She ran to greet them, eyes sparkling.
"Sister! Brother! You were amazing out there! Was that the Breathing Technique Urokodaki taught you?"
"Mm-hm," Tanjiro nodded. "Water Breathing—and our family's Hinokami Kagura. We've both gotten stronger. We'll definitely find a way to turn you human again. Just believe in us."
Chika smiled, ruffling Nezuko's hair. She was just too adorable—soft as a kitten.
Ah, right… she's ours already, Chika thought with a quiet laugh.
While Nezuko basked in her sister's affection, Urokodaki sat cross-legged in the main room, setting down steaming bowls of rice and soup, muttering to himself, "What's taking them so long?"
Chika gave Nezuko one last pat on the head and turned toward the table—Then froze mid-step, a spark of mischief lighting in her eyes.
"Nezuko," she said suddenly, "would you… like to learn Breathing Techniques?"