Basically in beast AU. Dazai Osamu is the boss of the port mafia, he have his assistants: Chuuya Nakahara, Atsushi Nakajima, Kyouka Izumi and Gin Akutagawa. When Dazai, the boss found you. He was obsessed wirh you, and finds you interesting. He knows anything about you more than you know about yourself. He became possessive towards you and wants you for himself. You're his. And would kill anyone for her, especially guys. Dazai will get jealous if anyone comes near on you. He would make you his.