Tanjiro froze for a second, staring at his blade.Had it… just caught fire?
The rhythm of his breathing broke, and as soon as it did, the flame on the sword winked out—snuffed as suddenly as it had appeared.The rush of power vanished, replaced by a crushing tightness in his chest.
"E–Elder Sister…! There was fire! I saw it! Flames, right?!"He clutched his chest, still reeling from the strain, but the wonder in his voice drowned out the pain.
It wasn't like the water-patterned aura of Water Breathing—but it was real, undeniably real.A heat that burned with purpose.
Chika tapped her chin, pretending to ponder. "Looks like our family's Hinokami Kagura might really be a breathing style too. Why don't we go ask Master Urokodaki?"
Of course, she already knew that was the next step. There was no reason to keep it secret, and she was curious to see the old man's face when he saw it himself.
Tanjiro nodded eagerly. The siblings turned and dashed back toward the cabin.
When they burst through the door and explained, Urokodaki blinked behind his tengu mask.A family breathing technique? Producing fire?He frowned. "Fire? That's… the domain of the Rengoku family's Flame Breathing, isn't it?"
Still suspicious, he motioned for Tanjiro to demonstrate.
Five seconds—that was all it took.Tanjiro inhaled, exhaled, and the blade ignited in his hands, its edge flaring bright as sunrise.
For several long moments, Urokodaki said nothing.His masked face was unreadable, but even Chika could imagine the stunned expression beneath it.
"How… How is that possible?" he muttered. "The Kamado family… and the Rengoku line? No, the flame looks different. Softer… rhythmic. Could it be a derivative? Another branch of breathing?"
He circled the siblings like a scholar inspecting an ancient relic, mumbling calculations under his breath.Most Demon Slayers, even Hashira, barely understood the origins of the Breathing Forms. The idea of a Sun-derived style was practically myth.
After several minutes, Urokodaki sighed, defeated. "No… I can't place it. Let's call it a derivative for now."His gaze flicked toward Tanjiro—pale, trembling, almost swaying on his feet.The boy had only used it twice, but he looked as if he'd run for miles.
"This breathing eats through your stamina," Urokodaki concluded. "Don't touch it again until your foundation is solid. You'll destroy your body before you master it."
Tanjiro nodded weakly. "Y-Yes, Master…"
Once they left the cabin, Chika had already coaxed the breathing pattern out of her brother—no threats needed.Being the eldest sister had its privileges, after all.
But even with the secret in hand, she didn't begin practicing right away. Urokodaki was right; Hinokami Kagura was too taxing for her current body.Building a base came first.
Tanjiro rested briefly, then threw himself back into training.That was just the kind of person he was—unstoppable once he set his mind to something.
Days passed. Then weeks. Then—an entire year.
Urokodaki stood at the edge of the training field, the morning wind brushing past his mask. Beneath it, he wore the expression of a man caught between awe and exhaustion.
Before him, Tanjiro was swinging endlessly, each strike steadier than the last.Chika stood beside him, acting as both sparring partner and assistant instructor, her movements precise, her composure unshakable.
"…Unbelievable," Urokodaki muttered. "A single year, and they're already beyond anything I've planned."
He'd heard stories—rumors of prodigies who became Hashira in mere months—but he'd never thought he'd train two of them at once.
Have I already taught them everything?
He looked up at the rising sun, its light catching on the edge of his mask.Then he looked back at the two siblings—the boy with his boundless energy, and the girl whose calm presence radiated quiet strength.
Chika brushed a lock of crimson hair behind her ear, sunlight glinting in her eyes.Her poise carried a natural grace that even Urokodaki found disarming.
So this is what she's like when she isn't cracking jokes, he thought. Almost… elegant.
When they noticed his call, Tanjiro came running like an eager puppy, while Chika walked with her usual composed air.
Urokodaki cleared his throat, ready to tell them what he'd planned to say:You've learned all I can teach. It's time to face the Final Selection.
But before he could speak, Tanjiro beat him to it."Master Urokodaki! What are we learning next?!"
The old man froze mid-sentence.
That fire in Tanjiro's eyes—his hunger to learn—was pure, almost painful to look at.
How could I send these two to die so soon?
His chest tightened. For years, his students had gone to the Final Selection and never returned. He trusted his training, yes—but how many times had that trust led to another funeral?
No. Not yet. Not until they were truly ready.
"There's… one last thing," he said finally, straightening his posture. "A final lesson before the Selection."
The twins looked up at him expectantly.
"The technique's name is…"He paused, letting the words hang in the air.
"…Total Concentration — Constant."