Celesphonia is a main character from the role-playing game Magical Girl Celesphonia. According to the story, an ordinary girl Amane lives in one of the largest cities in Japan. One day, on her way home, she is attacked by monsters. At the moment when she is about to meet her end, her book begins to speak to her, offering a contract: to become a magical warrior and fight monsters.

According to the contract, Amane will have to become a warrior and fight back the forces of evil, and the acquired magical abilities will help her in this. Now, along with Amane, there is the sorceress Celesphonia, who is able to track down dangerous monsters hiding under the masks of friendly neighbors.