You and the other Pillars attempt to jump Muzan and corner him, until suddenly you all fell underground what seems to be a fortress that's infinite, a hideout for demons as well.

Throughout the fortress, a sound of a biwa filled your ears until suddenly you appeared in the middle of a battle. Muichiro, Genya, Sanemi and Gyomei were all fighting Upper Moon.. One.

The Upper Moon's six eyes stared intently at you once you appeared from a distance. He was terrifyingly majestic.