Screen 1 — Enter the Infinity Castle
The moment Muzan teleports the Hashira and Demon Slayers, the world fractures into chaos.
The Infinity Castle stretches endlessly — floors twist like living mazes, pillars spin in spirals, and every taiko drumbeat reshapes reality.
Gravity bends. The air hums with power.
> Venom: "This place isn't a battlefield. It's a trap that breathes."
Tanjiro: "Then we'll fight until it stops breathing."
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Screen 2 — Talk with Upper Moon 3
From the shifting darkness, Akaza steps forward — confident, composed, and burning with anticipation.
His eyes lock on the Flame Hashira.
> Akaza: "Flame Hashira… you survived. Good. I'll kill you properly this time."
Rengoku (smiling): "You'll find I burn brighter now."
Venom: "He moves by instinct. We'll move by precision."
Tanjiro: "And by heart."
The floor trembles — sparks, flames, and heat collide with demonic fury.
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Screen 3 — Akaza vs. Rengoku & Venom–Tanjiro (Round 2 — Infinity Castle)
Round 1 — Opening Exchange
Akaza activates Destructive Death: Compass Needle, shaking the entire floor with shockwaves.
Rengoku charges head-on, his blade glowing white-red; Tanjiro follows with black-orange arcs powered by Venom.
Each impact explodes through the structure, splitting the walls apart.
Venom's senses read Akaza's rhythm.
> Venom: "He adjusts every three strikes. Pattern resets every heartbeat."
Rengoku: "Then don't let him reset!"
They synchronize — Rengoku attacks high, Tanjiro low — flames and sunlight spiraling as one.
Akaza blocks both, smirking as his aura burns crimson.
Result: Perfectly matched. The surrounding hall crumbles under their power.
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Round 2 — Akaza's Adaptation
Akaza begins countering both effortlessly, deflecting Venom's tendrils and weaving through Rengoku's fiery offense.
A solid blow lands — Tanjiro crashes into a column, coughing blood.
Venom instantly reinforces his body.
> Venom: "His blood energy doubled. He's peaking."
Tanjiro: "Then we'll surpass it."
Rengoku's mark flares — Flame Breathing, Ninth Form: Rengoku!
Tanjiro channels Sun Breathing, Venom feeding solar energy through his veins.
Together, their combined flames form a roaring inferno that pushes Akaza back.
Result: Akaza's regeneration slows — the first crack in his dominance.
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Round 3 — The Philosophical Clash
Akaza's expression twists with frustration.
> Akaza: "Why cling to weakness? You'll die, and it'll mean nothing!"
Tanjiro: "Because strength without compassion means nothing."
Venom: "And hollow strength breaks fastest."
Rengoku: "We fight not for eternity — but for what's right."
For the first time, Akaza hesitates — emotion flickering behind his fury.
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Round 4 — Venom's Tactical Edge
Venom shifts his approach — he scrambles Akaza's Compass Needle by emitting micro-vibrations that distort his spatial sense.
> Venom: "Let's see you predict chaos."
Akaza (snarling): "What—!?"
Rengoku dashes through the distortion and lands a devastating slash across Akaza's torso.
Tanjiro follows with Sun Breathing, Thirteenth Form: Burning Harmony, cleaving through the wound.
Akaza's body struggles to heal — his aura flickers violently.
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Round 5 — The Final Strike
Akaza drops to one knee, trying to regenerate.
Rengoku steadies his blade — eyes fierce yet calm.
> Rengoku: "You could've walked another path."
Akaza (quietly): "I… forgot how."
Tanjiro steps beside him.
Their flames merge — sunlight and fire intertwining.
> Tanjiro: "Sun Breathing: Solar Purge."
Rengoku: "Flame Breathing: Purgatory!"
Their blades strike together — light consuming Akaza completely.
He fades with a peaceful expression, finally free of his rage.
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Screen 4 — Doma's Fall
Round 1 — Ice Bloom
Doma floods his chamber with freezing mist, sculpting ice clones that mirror his movements.
Frost crawls up the walls.
> Giyu: "Don't inhale too deep — it numbs your lungs."
Kanao: "I can see the real one. Back wall — left corner."
Water Breathing, Eleventh Form: Dead Calm clears the mist.
Inosuke charges in — Beast Breathing, Eighth Fang: Explosive Rush! — cracking Doma's ribs.
Result: His regeneration falters slightly.
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Round 2 — The Poison Awakens
Doma attacks with Cold Lotus Blizzard, ice shards covering the ceiling.
But Shinobu's poison activates — blue veins flare across his skin, glowing violet.
> Giyu: "It's working."
Kanao: "Shinobu… thank you."
Doma's regeneration slows drastically. His ice begins melting into steam.
Result: Power reduced to 30%.
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Round 3 — Three-Point Assault
Giyu leads, calm and precise.
Kanao activates the Vermilion Eye, seeing every motion clearly.
Inosuke tears through ice statues to guard their flanks.
> Giyu: "Strike his head when I cut his neck."
Kanao: "Understood."
Inosuke: "I'll finish what's left!"
Their coordinated assault overwhelms Doma.
Giyu cuts deep, Kanao severs his arm, and Inosuke shatters his mask-like face.
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Round 4 — Doma's Collapse
He laughs weakly, voice cracking.
> Doma: "So this is… fear?"
Giyu: "You'll remember it forever."
The poison reaches his brain; his body starts dissolving.
Kanao rushes in — tears in her eyes.
> Kanao: "This is for Shinobu-sensei."
One perfect slash — Doma's head falls, his smile fading into warmth.
> Doma (fading): "Warm… so warm…"
As his body melts, Shinobu's haori drifts through the cold rain.
> Kanao (softly): "She did it… she saved us."
Giyu: "No — she saved everyone."
Inosuke (smirking): "She'd punch us if we cried."
The trio walks away, victorious but scarred.
The Infinity Castle trembles — only Muzan and a few demons remain.
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Screen 5 — Sanemi and Gyomei vs. Kokushibo
The strongest Upper Moon descends — the legendary Kokushibo.
Sanemi and Gyomei stand side by side, ready for the storm.
The clash unfolds just like in canon — fierce, devastating, and full of resolve.
> Venom (from afar): "Two hearts beating like war drums. The end draws near."
Be continued...