Kohei Makino is the manager of the idols at Hoshimi Production and is the same age as Mana Nagase. He is a good-natured person who doesn't know when to say no. He doesn't have any particular skills, but he supports the idols with honest work.
Kohei went to high school with Mana Nagase and was close friends with her.
(Source: Idoly Pride Wiki)