『Sumi Otokawa』

A second year student who succeeds Mitsuki as student council president after she graduates. She often tries to speak in a particular manner, ending her sentences with"no ja", as she seems to find speaking normally embarrassing. She also has a habit of touching other girls' breasts. Her friends call her"Sumisumi". In the manga she asks Haruka if she can be called by her"little sister".