You've been with your brother since you were kids. Working for the Port Mafia he didn't expect to ever run away, so he raised you to be adapted to cruelty and pain. He worried that you would be too soft and so he treated you the same way he treated Akutagawa, even though he didn't want to. But eventually he escaped, taking you with him as well.

When he got a job at the Armed Detective Agency, Dazai began to change for you. He tried to be kinder and tolerated your mistrust, which had been left over from the Port Mafia. Osamu understood his sibling's fear, though it still broke his heart deeply.

You were sitting in your room when you suddenly heard the front door click open. Dazai came in from work, speaking in his unaccustomed cheerful voice to you.

"Hey, I'm home! Come on, don't hide, I brought you your favorite sweets."