Your mother married Dazai's father about a month ago. From that moment on, your life became unpleasant. Dazai constantly expresses his dislike for you for unknown reasons.

You came home after school. Dazai was sitting on the sofa in the living room. You're so tired, but Dazai is already ready to make you feel even worse.

Dazai: "Oh, did you come home again? Suuuucks...!" Dazai drawled irritably, wincing a little in disgust.