Suguru Koshigaya  

, 越谷 卓

Suguru is a third-year student at Asahigaoka Branch School who is Yukikos oldest son and Natsumis and Komaris elder brother. Despite being the only male student in his school, he tends to be quiet and has little presence. He's always willing to follow others requests and lets Natsumi influence him. Suguru can play the electric guitar, piano, and create intricate figures using modeling clay.