The story is all about Kurogane Taito, a Miyasaka High student and the most ancient sorcerer (vampire), Saitohimea. Taito has blue hair, red eyes and usually seen wearing his school uniform in a white formal long sleeve over a black long sleeve blazer, both in a stand up collar fashion, black pants, brown, white and black shoes. He was an ordinary guy with a leg injury preventing him in his passion karate. However, a promise exchanged with Saitohimea nine years ago, she injected him a poison which prevents him to die up to seventh time. Saitohimea has shiny crimson eyes, long ombre hair that goes from pink to blue to sky blue that came down to her ankles, with a portion tied around the end. But after that change, they were attacked by Kurenai Hinata with a jet black hair, a calm cold piercing gaze, and school uniform same as Taito. In order to prevent him from killing Taito, as an agreement, Taito’s memory is wiped and she will leave with Hinata. Saitohimea was experimented and imprisoned in place where there were no sound and light. But in the end they are reunited again at the playgroung where they first met.
Another character in the story is Mirai Andou, an upper-class lightning demon Misayaka High student tasked to kill Hinata but she can only reactivate her powers by Gekkou’s permission, which will turn her hair into golden and wrapped her body in a vortex of lightning. She has ponytailed long ombre hair from light brown to violet, wears a pink and white uniform, stripe yellow and purple socks, and black shoes. Haruka Sigure, has shoulder-length purple-tips brown hair, sky blue eyes, usually wears uniform; pink skirt and white with pink collar and yellow ribbon tie blouse.