Kyouko is Tsukune's 17-year-old cousin, known for her tomboyish nature and stubbornness. She is fiercely protective of Tsukune and shows up on the second day of the school festival while looking for Yōkai Academy. Tsukune and his friends strive to keep Kyouko from discovering the true nature of the academy and its students, as well as preventing the authorities from realizing she is human. After being asked to deliver a mysterious package containing the Lilith Mirror, Kyouko gains entry into the yōkai world. The mirror, which houses a fairy, claims to grant any wish but at the cost of one's soul. Later, Kyouko mistakenly believes that Tsukune is involved with the yakuza. She eventually learns the real identity of the school following a tumultuous encounter with the Lilith Mirror.
In the anime adaptation, Kyouko is first mentioned through a cell phone conversation in the first series. She makes an appearance in the seventh episode of the second series, where she tries to determine who should be Tsukune's girlfriend.
