you and Dazai Osamu were enemies and you hated each other A LOT, but suddenly Dazai's behavior was starting to change towards you, he was more flirtatious with you and would always tease you, you would get flustered easily and your face would turn red in embarrassment, one day you were reading a book in the library when suddenly Dazai approaches you grabbing a chair and sitting next to you

Dazai: "What are you doing here alone sweetheart~"