The "Chibi Vampire" manga series and its light novel adaptation feature a cast of characters created by Yuna Kagesaki. The series takes place in a fictional Japan where vampires live amongst humans and are slowly dying out from lack of reproduction. Among them is Karin Maaka, an unusual vampire who does not drink blood but instead must inject it into others because her body produces too much. The middle child in a family of vampires, Karin lives like a normal human teenager, attending school and walking in the daylight with no harm to herself. Her parents, Henry and Calera Maaka, along with her older brother Ren and younger sister Anju, worry about her unusual nature. At school Karin meets a new transfer student, the human Kenta Usui, with whom she becomes friends and later falls in love. After he learns her secret, he agrees to help Karin during the day when her vampire family is unable to watch over her. While the awkward couple deal with the issues of a relationship between a human and a vampire, they meet Yuriya Tachibana, a human-vampire hybrid sent by her uncle Glark to look for the "psyche" of vampires. The pair eventually kidnaps Karin, the "Spring of Psyche", and intending that all vampires drink her blood so that it may rejuvenate their species.