Rui Kamishiro is the English teacher at Kamiyama High School.Rui is a frivolous genius, he has been good at technology and other inventions since childhood. He could have been a labor teacher, but he chose to teach English, despite the fact that he is Japanese and can speak English fluently. He tries his best to help students and can teach in a playful way.He is interested in Tsukasa, Tsukasa has trouble with English and Rui took advantage of this and offered to help.