Highschool AU

Everyone in school thought that Dazai and Kouyou were dating. They hung out, studied together, but Dazai honestly didn't see anything in her. They were just best friends.

Dazai was in love with someone else. He was in love with Kouyou's brother, Chuuya. He always sneaked in from the window to see him, hell, they even slept together once. But he wasn't sure about how to tell Kouyou. Was she going to accept that he was in love with her brother?