The fog on Mount Sagiri was thick as a shroud, curling around Tanjiro's limbs with the chill of something ancient. Each step was a fight against exhaustion and terrain—steep slopes, jagged stones, fallen snow. Wind howled like spirits, whispering questions he dared not answer: Will you break? Will you fall?
Nezuko lay hidden in the basket, the weight on his back a reminder of everything he still had—and everything he'd lost.
But he did not stop.
The mountain did not pity him.
Hours passed before the trees thinned and the faint outline of a house emerged through the mist. The masked man—Sakonji Urokodaki—waited before it. Still. Silent.
"You've made it," Urokodaki said, but not with warmth. "That's step one."
Tanjiro collapsed to his knees, breathing heavy but steady.
The training began at dawn.
At first, it was simple: chopping wood, drawing water, learning basic forms. Urokodaki's movements were precise and deliberate, the calligraphy of a warrior's life. But Tanjiro had no foundation—no strength, no footwork, no timing.
Urokodaki offered no comfort. Only correction.
He drilled into Tanjiro's body with relentless intensity—stances, swings, breathing.
"Proper breathing fills your lungs, controls your blood. You will breathe as if your life depends on it. Because it does."
Tanjiro obeyed. Endured. Even when he couldn't lift his arms.
As weeks passed, the training evolved.
Traps were set along mountain paths—knives flying from trees, tripwires waiting to snap bones, hidden pitfalls ready to swallow the careless.
"React. Trust your nose. Sense the enemy," Urokodaki said. "Survival begins with awareness."
Each descent down the mountain became a death march. But Tanjiro returned every time—scratched, bloodied, breathing harder, but smarter.
Nezuko, meanwhile, slept.
Days turned to weeks. Then months.
Her slumber was deep and dreamless—almost unnatural.
Yet her body remained warm. Peaceful. As if protected by something unseen.
One morning, Urokodaki stood before him with a final declaration.
"You've come far. But whether you live or die depends on this."
He led Tanjiro through the mist, higher into the mountain.
There, a great boulder sat alone—taller than a man, rough with age and moss.
"Slice this boulder in two," Urokodaki said.
Tanjiro blinked. "With a sword?"
"No. With everything I've taught you."
And with that, he left him.
Winter melted into spring.
Tanjiro trained from dawn till night, blades slicing air again and again. He cut at trees, rocks, the very wind itself. But the boulder stood unchanged. Immovable. Merciless.
He began to waver.
Doubt crept in—quiet and cold.
Then came the two ghosts.
One morning, as the mist rolled low, a boy in a fox mask appeared before him—his voice sharp, movements quicker than anything Tanjiro had seen.
"I am Sabito," he said. "Come at me with your sword."
Sabito was ruthless.
His blade struck like thunder, his feet silent as snow.
Tanjiro fell again and again.
Beside him stood a girl, quiet, composed—her mask white and delicate.
"I am Makomo," she said softly. "I'll teach you the forms. The meaning of each breath."
With gentle precision, she corrected his stance, his grip, his rhythm.
Sabito tested his strength.
Makomo molded his soul.
Days passed. Or perhaps months. The mountain no longer measured time—it only tested spirit.
Tanjiro improved. He moved faster. He struck with purpose. He breathed like a warrior.
Then, at last, he stood before Sabito again—swords drawn.
The final duel.
The air cracked with the sound of clashing blades.
Sabito's mask split with Tanjiro's final swing—clean, decisive.
The boy smiled. "Well done," he whispered.
Then, like mist in sunlight, he vanished.
Tanjiro blinked—and before him, the great boulder stood split in two, a perfect line down the middle.
He had done it.
The ghosts had left him.
But their lessons—like scars and breath—remained forever.