Kobachi is Miko's classmate with the glasses and a member of the disciplinary committee. She has been looking after Miko for over 10 years.
SpoilerThough she doesn't love him in a romantic way, she has liked Yu Ishigami since middle school. She believes that Tsubame Koyasu is a kind person and is therefore supportive of Ishigami's feelings for Tsubame, despite her friend Miko being in love with Ishigami as well.