Kurasaki Minato

Minato Kurasaki is a roommate of Nanami at the female school's dormitory, after she, Riko and Manatsu found Nanami and Shuuichi in the bathroom, she agrees to let him live with them for the summer vacation and states that each one of them have a different speciality so they can probably set time aside for some one-on-one study sessions at the condition to be called onee-chan, since she asked for a little brother as a Christmas present when she was a kid.