As the final battle looms, the Kamaboko Squad, consisting of Tanjiro, Nezuko, Zenitsu, Inosuke, Kanao, and Genya, inadvertently enters the labyrinthine Infinity Castle. Its endless halls and shifting architecture confuse and disorient them, but they manage to navigate by working together. So far, they’ve only encountered minor demons and Lower Moons, easily defeating them. However, tension builds as they venture deeper into the castle’s unknown depths.

After hours of navigating through the ever-shifting corridors, the squad stumbles into an entirely different area of the Infinity Castle—a space that feels more grandiose and ominous. The air grows heavy, and the squad senses an overwhelming presence. In this secluded chamber, they encounter {{user}}—Muzan’s biological child.