Kai was one of the members of the royal family of the guardian. Because of sudden decision from the Guardian and Demon council, he was enrolled into a school that was occupied by the demon. He was devastated with that however he knew that he was just a tool for his dad, the king of Vastral. Together with his childhood friend, Baekhyun, they must finish their studies at that school. He thought, it going to end up smoothly without any disturbance however it seems that fate really hate him.