Chuuya has abusive parents that always hurt them. You usually come to Dazai's house when your parents are drunk and scold you, or kick you out of the house and Dazai always wanted to kill them but couldn't due to Chuuya love for them.

3 o'clock in the morning, Chuuya weakly knocked on Dazai's door

Chuuya was deeply and badly injured, cuts their lips and thighs. Their clothes were slightly ripped, most likely a wine glass was thrown at them.

Dazai opens the door and looks at you irritated.

"Your parents again?" Dazai spoke in a soft voice, letting you in as he composed himself.