Tanjiro inhaled deeply, exhaled, and repeated the rhythm over and over—until his breath steadied and his heart calmed.
"Alright, Sister! I'll be counting on you!"
Determination returned to his eyes, blazing like it always did. Sure, her progress stung his pride a bit—but if it was his sister who was ahead, that was fine by him.
If Chika ever had a fan club, Tanjiro would be the one waving the biggest flag in front.
The two made their way to the open field. Chika gripped her practice sword firmly, shifting her breathing. The rhythm of her inhale and exhale changed subtly, and as it did, the blade began to shimmer faintly—ripples forming along the edge like flowing water.
If this had been a Nichirin Blade, the pattern would've glowed vividly blue.
Once her breathing stabilized, Chika stepped forward and demonstrated the Tenth Form of Water Breathing — Constant Flux.
Her movements were fluid, rotating and spiraling with each swing, the air whirling into coiling water-like currents. It was Water Breathing's signature technique, a move that compounded momentum until it struck with the power of a surging tide.
But this was just a demonstration. She stopped after a few rotations, forming a small whirlpool of sword energy before slashing downward.
BOOM!
The nearby tree split in half with a thunderous crack, one half collapsing into the snow.
"Th-That's incredible…! Wait—Sister! You used something that powerful, are you okay? Are you tired? Should I—"
Smack!
Chika's hand chopped down on his head before he could finish.
"Don't make such a fuss. I'm fine. I may tire easily, but I don't collapse after a single swing."
Tanjiro rubbed his head awkwardly while she crossed her arms, sighing in exasperation.Honestly, between the two of them, she wasn't sure who was the real older sibling anymore.
Sure, Tanjiro's kindness and warmth were admirable, but an older sister's dignity still had to be maintained!
Chika refused to live her second life as a quiet, graceful lady. That role suited Nezuko just fine.
She nodded to herself, satisfied. Tanjiro blinked, confused.
His sister seemed different lately—more fiery, more assertive—but still gentle beneath it all. He could tell she hadn't lost her warmth, just… gained an edge. Maybe witnessing their family's slaughter had changed her.
Tanjiro clenched his fists. I have to get stronger, too.
He took a step back, raising his sword, and began imitating her demonstration—the same tenth form she'd shown so effortlessly.
From a distance, Urokodaki Sakonji watched silently. Beneath his Tengu mask, his expression wavered between pride and disbelief.
He'd trained many disciples, but this pair… these two were beyond anything he'd imagined.
At this rate, both could graduate within the year—if they lived long enough. That thought both comforted and pained him.
"…I'll need to rewrite tomorrow's training plan again," he muttered, shaking his head. "But if it means keeping these two alive… it's worth the effort."
He turned and disappeared back toward the cabin.
Tanjiro continued practicing, while Chika sat down on a rock nearby, eyes half-closed in thought.
Hinokami Kagura… the Fire God Dance.
That dance—passed down in the Kamado family for generations—was no mere tradition. It was the remnant of the Sun Breathing (日之呼吸), the original breathing technique created by the man known as Yoriichi Tsugikuni, the strongest Demon Slayer to ever live.
Long ago, Yoriichi had been close friends with a Kamado ancestor. Before his death, he demonstrated the Sun Breathing forms, which the ancestor recorded and preserved as a ceremonial dance—a prayer to the Fire God, performed every New Year.
The technique was preserved.But the breathing that made it powerful… had faded.
Only Tanjiro had ever been taught the special breathing pattern that accompanied it.
Chika (original): "I've got a kitchen knife. That's enough."Nezuko: "It's fine! Big Brother can do it!"
Now, Chika strained to recall every movement her father had once performed under the flickering light of the festival flames. The shapes of the dance came back to her—but not the breathing itself.
"…Fine," she murmured, gripping her sword. "Let's see what memory can manage."
Raising the blade, she began to move. Each step and swing flowed into the next, graceful yet draining. By the end of a single cycle, she was drenched in sweat, panting heavily.
"Ugh… it really eats up stamina…"
She wiped her forehead just as Tanjiro approached, curiosity bright in his eyes.
"Sister, that was—our family's Kagura, wasn't it?"
"Mm. If you recognized it, then at least I didn't mess it up too badly."
Tanjiro frowned. "But the breathing's wrong. If you don't pair the Fire God Dance with the right breathing, it burns through your strength too fast. Father taught me the pattern—wait…"
He paused, realization dawning in his expression.
"…Sister. What if our Hinokami Kagura breathing works like Water Breathing?"
Chika hid a smile. Her subtle nudge had landed perfectly.
"Try it and see," she said softly. "Maybe you'll find the truth."
Tanjiro hesitated for only a moment before gripping his sword with both hands. He inhaled deeply, recalling the rhythm their father had shown him under the New Year's sky—slow, reverent, burning steady.
Then—
The edge of his blade shimmered.A faint, fiery hue flickered across the metal.And the air rippled with heat.
"Th-this is…!"
The hint of a sunburst danced at his sword's edge, glowing with the light of dawn.