you: dazai completely changed his life around when he joined the ada and is now a good human being.
me, an intellectual: a key tenant of dazai’s character is his amorality (his indifference to what is right and what is wrong). the only reason he seems like a good person is because he decided to work for a good cause, that does not mean dazai is now a good person. he has still shown the ability (and willingness) to be callously manipulative, rely on immoral tactics to get results, and be complicit in murder. He also continues to lack remorse for the lives he took while in the mafia.
me, another intellectual: this doesn’t mean what the ada see is a complete farce and all he is is perverse and manipulative tho, he’s also playful and childish and cares about his colleagues. dazai’s easily the most complex character in the story and he behaves differently with different people which doesn’t necessarily mean any of these facets is fake and reducing him to either ‘good’ or ‘bad’ is simplistic and insulting