---

The Infinity Castle moaned under its own weight. Its shifting walls groaned like wounded beasts. A soft wind blew through the blood-soaked halls, carrying whispers of those already lost.

Zenitsu stumbled forward.

His yellow-and-orange haori was shredded. Cuts covered his arms. His breathing was ragged. Every step felt heavier than the last. The echoes of battle still rang in his ears.

His sword dragged beside him, leaving small sparks each time the chipped blade scraped against the floor.

"I should have died with them..." he thought, blinking through the sweat and blood stinging his eyes.

"Why... why am I still alive?"

The thought hit him harder than any demon ever could.

Tanjiro. Inosuke. Nezuko. Giyu.

All of them had gone ahead, deeper into the castle, chasing Muzan’s presence. But when the castle shifted... Zenitsu was separated. Trapped. Alone.

“I was never supposed to be the strong one,” he whispered to no one.

The hallway split open ahead of him — wide, cold, and silent.

Then…

Mist rolled in.

A laugh. Elegant. Careless. Cruel.

From the left, a figure emerged through the frost, twirling a bloodstained fan. Layers of robes fluttered like silk in the breeze, and his smile could’ve belonged to a doll carved from ice.

Douma.

"Ah~ What a surprise," Douma said, amused. "A little sparrow fluttering through this twisted maze?"

Zenitsu froze.

His pulse quickened. Not from excitement. Not from rage. From raw fear.

He tried to lift his sword — his body wouldn’t respond.

"You're trembling," Douma noted, almost kindly. "Cute."

And then—

A rumble.

Footsteps. Heavy, exact. Confident.

From the shadows to the right stepped Akaza.

Muscles coiled with killing intent. His red tattoos glowed faintly under the flickering light.

“You’re the Thunder Pillar’s apprentice,” Akaza said coldly.

Zenitsu didn’t respond.

He couldn’t.

His legs screamed at him to run. His lungs couldn’t find air.

His hands? Still trembling.

“I can’t beat them,” he thought. “Not both. Maybe not even one.”

Then — a voice echoed inside his skull.

Old, broken, but steady.

“You don’t need to be fearless. Just choose to move. Just once.”

His master’s voice.

Jigoro’s voice.

Zenitsu took a breath.

The air around his feet sparked.

Douma chuckled. Akaza tilted his head, intrigued.

Zenitsu vanished.

“Thunder Breathing… First Form…”

In a blink, he appeared in front of Douma.

“Thunderclap and Flash — SIXFOLD!”

CRACK.

BOOM.

The hallway exploded in golden light. Dust shot up in all directions. For a moment, the mist parted — revealing the storm inside.

Douma’s cheek bled.

Akaza's arm was slashed.

Zenitsu stood between them. Blood in his mouth. Knees shaking. But his blade was steady.and bit broken

“I’m afraid,” he whispered, eyes locked on the two Upper Moons.and was full form aggression in his eyes

“But I’m still here.”

Far behind them, deep in the shifting castle, something ancient stirred.

Six eyes blinked in the dark.

Kokushibo had begun to walk.

The sound of thunder still echoed through the hallway.

Douma slowly wiped the blood trailing from the cut on his cheek. His smile hadn’t faded — it had sharpened. Like a needle.

Akaza flexed his arms, watching the fresh gash near his bicep slowly heal.

Zenitsu panted. His breath was shallow. His knees shook.

He had moved before he could think — again. But this time… he hadn’t blacked out.

He’d done it awake.

“I’m... awake?” he whispered to himself, stunned.

His heart hammered in his chest. Not from fear — no, something else was crawling inside him now. Something old. Something he had never dared trust before.

Belief.

---

Douma spread his arms wide, twirling his fan lazily.

> “Ara~ you really are entertaining, sparrow. A little bite in you after all. But...”

“Don’t misunderstand. That was cute — not dangerous.”

A massive wall of ice lotus spears formed around Douma in a single pulse.

Zenitsu’s eyes widened.

The cold hit him like a wave. His joints ached. His fingers stiffened.

Then — a red flash.

Akaza vanished.

In a blink, his fist was already in motion — aimed directly at Zenitsu’s head.

"Destructive Death: Compass Needle."

Zenitsu barely moved.

The wind from the punch ripped his haori sleeve clean off.

He flipped back, sliding across the floor. His breathing staggered, but he didn’t fall.

---

> “Too fast…”

“Too strong…”

He landed and gasped for air.

> “I can’t fight both. I can’t...”

“Run,” whispered the voice in his mind. “This is where you die.”

But his feet didn’t move.

“Thunder Breathing…”

He gritted his teeth.

“Fifth Form…”

He twisted, lowered his body to the floor, and vanished in a yellow streak, weaving through Douma’s ice barrage.

“Heat Lightning!”

A horizontal slash cut across Douma’s legs — shallow, but real.

Douma’s laughter stopped for a split second.

Akaza charged again.

Zenitsu met him halfway — his sword clashed with Akaza’s fists, lightning wrapping around the demon’s skin. Sparks flew with every strike.

But it wasn’t enough.

One clean punch landed.

CRACK!

Zenitsu flew across the hallway, smashing into a pillar. Blood flew from his mouth. His sword skidded across the floor.

---

He couldn’t breathe.

His chest wouldn’t expand.

Everything was spinning.

“This is it…”

“I can’t move…”

---

FLASHBACK – A small cottage, thunder outside.

Master Jigoro sits beside a crying boy.

> “Zenitsu… let the world shake. Let them all call you weak.”

“But when lightning strikes, it doesn’t ask permission. It just is.”

---

Zenitsu’s fingers twitched.

He heard footsteps.

Akaza approaching from one side.

Douma from the other.

No weapon.

No strength.

Just breath.

Inhale.

Lightning sparked at his heels.

“Thunder Breathing… Seventh Form…”

He pushed off with all he had.

> “Honoikazuchi no Kami!!!”

A dragon-shaped bolt of lightning tore down the hallway, roaring in defiance.

The entire castle shook.

Douma’s robes burned at the edges.

Akaza was blown back through a stone wall.

Even Kokushibo paused.

Zenitsu landed — hard — on his knees. Blood dripped from his nose. His body smoked.

But his eyes…

They were still burning.

---

🔥 To be continued...