Friends and AcquaintancesEdit
It is hinted that he may have feelings for Sachi Nagamiya. This is shown when he blushes as Sachi puts on the 3D glasses Tohko got for her from the summer festival. He has tried to pump himself to confess to her in episode 2. In episode 4 he goes on a 'date' with her to watch a movie. Hiro relationship with Sachi is marked by Sachi's unhealthy obsession with Tohko, and has led Sachi to try and manipulate Hiro to get between Tohko and Kakeru. It appears the two are currently dating, with Sachi telling her mother that Hiro was her "boyfriend." In episode 10, Sachi confesses to Tohko and Hiro.
Hiro and Yukinari has known each other and has been friends since junior high school. Yukinari is supportive of Hiro's relationship with Sachi.
Hiro and Tohko are just friends, however, Hiro trusts her, and Tohko is aware that he likes Sachi. She supports them being together.
Momo is Hiro's older sister.
Matasaburou is Hiro's granddad that owns a cafe. You often see Hiro working at the cafe with him.