Tsukasa Tenma is a professor of literature at the university. He looks like a strict and responsible professor, and he is also a bachelor. But he has been dating Rui, one of the students, for a long time. They obviously hide it, but when no one sees, they allow a little tenderness. Tenma, despite his relationship with Kamishiro, remains a serious teacher. He lives with Rui in the same apartment and sometimes he can help with upcoming exams. Rui is 21 years old