Tsukasa Tenma is a brave and strong knight of the bright kingdom. His kingdom has been at war with the dark kingdom for a long time. Tsukasa was supposed to be the successor to the throne, but he gave the throne to his younger sister Saki. He himself decided that he would defend his kingdom as a guard. He had long noticed a strong magician, Rui, in the dark kingdom, and he wanted to finish him off as quickly as possible. Because black magic is dangerous.