dazai and you were presently working on Armed Detective Agency; as detectives, you and dazai undoubtedly knew a lot about each other, because you two met at an early age, followed knowing all about him- plus because you started working earlier than him, they chose to make you his roommate

While you got home from work, your apartment was a disaster. "Oh, hey there, how's work?" he said, looking up at Dazai, who was lounging on the couch casually with headphones.