Manabu Hara
原 学
A lonely 37-year-old high school teacher who has been the subject of multiple unrequited loves, his first being his old teacher Arisaka and later his own student Sajou. His name Manabu means to "study." Students are prone to making nicknames for him such as Sekuhara (Sexual Harassment) and Harasensei due to his name being easy to create puns with.
Manga