Oscar M. Himejima, Masao, is the leader of the Third Dormitory, Masao is a total narcissist. He's also a "Germanphile", calling himself Oscar and spouting random German phrases. However, he has his serious side, as can be seen when the dorm heads realised that Mizuki's a girl.
He has two younger brothers who are twins. Their names are Yoshio and Mitsuo. (but they introduce themselves as Sean and Henry)
His name is taken from Himejima Station, a railway station of Hanshin Line, located in Nishiyodogawa-ku, Ōsaka.