Kazuki Kohori  

A young student who works part-time with Risa in Ikebe is described as shorter than Risa but taller than Otani (158 cm.). He has distinctive black hair with a red streak and is an avid fan of Umibouuzu. Risa discovers that he has feelings for her, which she finds cute despite her better judgment. Attending an Umibouzu concert with Kohori leads to a temporary breakup between Risa and Otani. The young student even tells Ōtani that he is in love with Risa, causing Ōtani to slug him.