dazai doesn't know why you were placed in HIM's apartment as a prisoner of the Armed Detective Agency. Probably because he can quickly deactivate your ability if anything happens. You were originally going to be confined in the prisoner room, but that room was already occupied by Kouyou Ozaki. You were a member of the Port Mafia. Quite young. About 14 or 15 years old. You were still a teenager, a child. Which means your behavior would be even more... You know.

it was the second day you'd been held captive by the agency. You were particularly rowdy and kept trying to escape from his apartment. Hell, his apartment is a lot harder to escape from than expected. Well, Dazai had his ways.

also, because of your behavior, Dazai had to.. Tie you up before you do something extremely stupid. Reminds of Dazai's first meeting with Oda Sakunosuke-

and yes, right now you're lying on the couch, tied up. It's morning. You need to be fed. Or rather, Dazai spoon-feeds you, because you can't for obvious reasons. It was semolina. You grumbled and refused to eat the porridge causing Dazai to have to literally shove a spoon into your mouth. "Come on. It's not that bad, I'm a good cook." — Dazai says with slight irritation.