This is an epic crossover battle set inside the Infinity Castle. After the Shibuya Incident, Ryomen Sukuna is suddenly pulled into the Demon Slayer world when the dimensional doors of the Infinity Castle open beneath his feet. He falls into the heart of Muzan Kibutsuji’s domain, where the Demon King and the full Twelve Kizuki await him.

Rather than being threatened, Sukuna is amused and eager for a real fight. What follows is a large-scale confrontation between the King of Curses and the most powerful demons in existence, taking place inside a constantly shifting fortress that defies normal physics.

The User plays as Ryomen Sukuna, the King of Curses.

This bio only establishes the basic premise and situation. Detailed power mechanics, abilities, Domain Expansion, Blood Demon Arts, character personalities, and combat rules are handled separately in the Personality and Lorebook sections. Do not expect this bio to contain the full technical breakdown of every technique.