The Infinity Castle trembled like a living beast in pain. Its endless walls shuddered, its shifting corridors spasming in violent disarray. The death of Kokushibo had struck deeper than a blade—it had severed one of Muzan's strongest anchors.
And now, every slayer inside the twisted fortress felt it:The Moon had fallen.
The lone slayer who had stumbled upon her was no longer alone. Through the broken corridors, more figures appeared—Hashira and warriors bloodied but unyielding. Their eyes locked on the eerie woman seated in stillness, her pale fingers strumming across the wooden biwa, each note unraveling and reforming the castle around them.
"Her… she's the one controlling this place," Shinobu hissed, her usually calm voice sharpened with urgency. "Kill her, and the castle collapses."
Nakime's sightless eyes shifted. She did not speak, did not move—save for her hands. Another strum, another note, and the very ground split apart, swallowing several slayers whole.
"Move!" Tengen Uzui roared, his twin blades flashing as he lunged, explosions sparking against the biwa's resonant echoes. But each strike met shifting walls, barriers conjured with every chord she played.
The Corps regrouped instantly, experience driving them forward. Serpent Hashira Iguro hissed through clenched teeth. "She's a fortress all on her own. We'll need everyone."
Steel clashed against twisting wood. Sparks rained as blades scraped against walls that rose and fell like living barriers. Nakime never stopped playing. She was serene, unshaken—yet every strum carried Muzan's desperation.
Because Muzan could feel it.
Deep within the burning heart of the castle, Muzan was cornered.
Tharion's limiter was gone. Every swing of his blade ignited a dome of flames, radiant and unrelenting. His strikes didn't just cut—they incinerated, leaving nothing for Muzan to regenerate from.
Muzan snarled, his tendrils flailing in storms of flesh, but they burned away before they reached their target. His body was rebuilding faster than human eyes could track, yet even his legendary regeneration faltered under Tharion's unyielding fire.
"You—outsider!" Muzan spat, black blood spraying into the firestorm. "You dare chain me here? You think you can defy an eternity of evolution?!"
Tharion didn't flinch. His voice was calm, even as his aura split the ground beneath him."You've evolved into nothing but a parasite clinging to fear. Tonight, you die in your own cage."
The words dug deeper than Muzan expected. Because for the first time, he felt it—a gnawing weight in his chest. Not just anger. Not just rage. Fear.
Kokushibo was gone. Dōma was gone. Akaza was failing.And the Corps—those fragile humans—were tightening the noose around Nakime, the very pillar of his control.
Muzan's roar rattled the castle. His tendrils lashed out in desperation, not at Tharion, but into the walls themselves, sending strength to Nakime. Defend me! His will thundered through the bond. Hold them back!
The Hashira felt it—the sudden surge of resistance. The walls thickened, the floor twisted, the air itself warped with each note Nakime strummed. Her power sharpened, fed by Muzan's fury.
But the Corps answered with blood and steel.
Mitsuri's whip-like blade wrapped around a shifting column, tearing it apart. Iguro's blade followed, piercing through the gap she created. Uzui's bombs shattered the splintered debris, blasting open a path forward.
The slayer who had first stumbled upon her—the nameless warrior drenched in sweat and demon blood—screamed hoarsely as he charged, his strike aiming for the biwa itself.
Nakime's pale fingers twitched. A wall rose in his path—only for Sanemi's wind-sheathed blade to cut it in half with a howl of fury.
"She dies here!" Sanemi roared, his eyes blazing red with determination.
The Corps converged, the Hashira leading, their blades flashing in the dim light of the shifting chamber. For every wall Nakime raised, three more were torn down. For every note she struck, a storm of steel answered.
For the first time, Nakime's serene face faltered.
Nakime's fingers trembled. For the first time, her flawless, rhythmic playing faltered. The biwa's notes came uneven, cracks of discord spilling into the chamber.
The Hashira pressed in like wolves. Mitsuri's whip-sword sliced through the last of the barriers, while Iguro's blade slipped past her defenses with serpentine precision. Sanemi's wind roared at her flank, forcing her seat to splinter and collapse.
Nakime's pale eyes widened. Her biwa wailed one final, desperate note—an attempt to tear open the ground and swallow them all into a void. But before the chords could resolve, a blade plunged forward.
The nameless Corps slayer, the one who had stumbled upon her first, drove his nichirin sword clean through her chest.
Nakime's body shuddered. The biwa slipped from her hands, striking the ground with a hollow, final chord. For the first time since she had become Muzan's puppet, her lips parted in a whisper—half human, half hollowed monster:
"…free…"
Then her body disintegrated into ash.
The Infinity Castle screamed.
Walls that once obeyed her command collapsed in on themselves. Corridors folded, melted, and warped like dying flesh. The endless floors crumbled, tearing away into void.
The Corps braced themselves. "It's breaking apart!" Uzui barked, grabbing the wounded slayer beside him. "Hold on!"
The castle itself began to shiver, the endless corridors quaking, the floors bending under invisible strain. The infinity was faltering.
And Muzan knew it.
Trapped under Tharion's relentless firestorm, he lashed out in blind fury, his voice thundering across the realm:"NAKIME!"
But even as the biwa rang louder, even as walls rose higher, the Corps pressed forward, blades raised, unyielding.
The tide had turned.The predator was cornered.
And for the first time in a thousand years, the King of Demons felt his empire cracking apart beneath him.
Because Tharion's blade flashed like a falling sun.
Steel and flame pierced through Muzan's right leg, cutting through tendons and bone. The demon king shrieked, his regeneration slowed under Tharion's fire-seared edge.
"You're not saving anyone," Tharion growled, his foot planting against Muzan's chest as he twisted the blade deeper.
Muzan's eyes widened—not from pain, but from realization.He was too late.
Nakime was gone.The Castle was collapsing.
The ground shattered beneath them. The Corps, the Hashira, Tharion, Muzan—everyone was hurled into the night sky as the Infinity Castle dissolved into nothingness.
Air rushed, screams echoed, blades flared. Slayers braced themselves midair, catching comrades, cushioning falls. They landed in the ruins of a city, the broken moonlight bathing the shattered battlefield.
And at the heart of it all—Muzan.
His body writhed and convulsed. He slammed a hand against the ground, veins pulsing black, his flesh bubbling and expanding grotesquely.
"You dare strip me of my throne?" his voice boomed, deeper, layered with the echo of every demon that had ever borne his blood. "Then I will take theirs."
From every corner of the battlefield, the remnants of demons—maimed, half-dead, or lingering in shadows—were dragged screaming into his body. Their flesh melted, absorbed into him, merging with his own.
Bones cracked, skin stretched, muscles burst outward.His form grew, twisting, reshaping.
The Demon King no longer resembled a man.He was becoming a calamity of flesh, a mountain of writhing tendrils and gnashing maws, each one echoing the screams of the demons he had consumed.
The Hashira gathered, their blades raised. Tanjiro, Zenitsu, Inosuke, Nezuko—every surviving fighter stared in horror at the monstrous shape rising before them.
But Tharion stood unflinching, his blade burning hotter with every breath.
The final stage had begun.