Hisui Kujō, nicknamed "Witch" or "Majo," attends Sainotama Girls' High School as a first-year student but rarely participates in classes. Her intense fascination with occult phenomena embodies her moniker. Hisui shares a unique bond with her twin sister, Kohaku Kujō, who asserts she claimed Hisui's "ability to communicate and sense of decency" during their birth—implying a supernatural or metaphorical link between them. This dynamic casts Kohaku as the socially adept twin, while Hisui remains defined by detachment and her occult endeavors.