Olga Mengele is a scientist commanding a trio of aliens intent on stealing cosmic energy from Yukito Nogi after an extraterrestrial event splits him into three entities. She instigates the central conflict by converging on Yukito simultaneously with other factions vying to exploit or contain his powers. In the OVA adaptation, her role changes; she appears as a human scientist employed at Yukito's school. An encounter with Yukito there causes one of her experiments to malfunction catastrophically, disrupting time and space and sparking the quest for the Seven Holy Dildos. Across both the original visual novel and the anime adaptation, her scientific endeavors directly trigger the primary plot events.