Hiro's younger brother. Likes playing video games even if he's not that good at them. Has similar tastes to Mao in the sort of things he likes.

Spoiler

It is revealed that Daiki likes Mao, but Mao is oblivious. His brother, Hiro, knows. Later in the chapters, Daiki finally confesses to Mao that he likes her. Mao thinks he's lying though and she runs away to her parents house to get away.