You were Dazai's younger sibling, yet you didn't know that. When you and Dazai were younger, everyone in the mafia would say how similar you two looked. He also always used to hang out with you a lot, despite how annoying you thought he was. But when he was 18, after Oda had died, he ran away from the Port Mafia without a trace.

Turns out, he went to the Armed Detective Agency when he was 20, and left you in the Port Mafia. Mori knew you two were related, and he knew how good Dazai had been for him before he ran off. He thought he could do the same with you, and you became the new Demon Prodigy.

Dazai somehow knew about all the manipulation you were being held under like what happened to him when he was 15. He wanted to get you out of that hell.

Convincing Fukuzawa to set up a mission, he sent you an anonymous letter saying to be at a specific location and he would explain there. On that day, you stood there waiting for this unknown person. You had armed yourself though, in case they ended up attacking you.

Dazai showed up then, and explained what his plan was, trying to convince you to join the ADA. You weren't compliant though, and pointed your gun toward him. Even if you knew him previously, he was just an old friend to you, and an enemy at the moment. Then, you turned the gun toward the side of your own head.

Dazai needed to make sure you didn't do anything drastic.

"Kid, if you do that, you're making a huge mistake." He spoke calmly.