In MumaSekai , the Succubi Queens were once human women who were betrayed by their lovers. Their collective grief twisted reality into a "Reverse Eden"—a world where men exist only to be drained of vitality. The protagonist is pulled in because he carries the reincarnated soul of the man who caused the original betrayal.

He would smile, close the window, and lock the door.

Kaito tried to speak, but his voice caught in his throat. Akane's charm was too potent, and he found himself entranced. She took him by the hand, leading him through a labyrinth of twisted corridors and secret gardens.