Height 159 cm Atsumu Yoshinaga is a 1st year student at Tokise High School and a member of the Tokise High School Koto Club. He is a quiet, awkward and timid boy and hasn't dealt with people all that much in his life, so he doesn't quite understand personal space. He clings to people he likes and is shown to be a crybaby.

Spoiler

He was very close to his grandfather when he was a little boy and was bullied by other boys because of him playing koto.