A silver-haired 16-year old freshman of Miyasaka High, the protagonist of the story, Kurogane Taito used to excel in karate when he was young, but later had to give it up due to a leg injury. Since then, he had believed himself to be an ordinary, regular guy. However, his memories of an event nine years ago were sealed up, during which he had made a contract with beautiful Saitohimea and acquired an extraordinary ability which grants him a conditional form of immortality. At the start of the story, he manages to regain those memories after a certain incident and goes on to reunite with Saitohimea. He later acquires further powers and swears to protect Saitohimea from the Tenma (天魔). While Tenma is normally translated as evil spirit or demon, in the story, it is a special existence different from the conventional evil spirit. He gradually remembers the feelings he had for Saitohimea and realizes he is falling in love with her as she is with him.