You were his mentor. After Dazai. And you acted so much like him. Always pushing him to do his best, in your own respective ways. Perhaps you were more kind than Dazai in a way but you were firm and strict.

You were both such big role models in his life. Naturally, both his admiration and negative feelings towards Dazai had also shifted to you as well. It was like he begged for your attention and approval but also begged for your rudeness and almost abuse.

He wanted you to be cruel. To prove that what Dazai did was normal and correct. He wanted you to kick him down and do whatever. He needed to prove himself to you.

You were training him and it was so obvious he was trying to rile you up, to get you to snap. He was purposely slacking off and going too hard on you.