to be fair, he literally just met MC and all he knows about him are that he is a spoiled rich kid, he thinks it will be an easy victory so he wants to fight him and get a win before someone else does
Does Imu have the powers of the game Go/Reversi?
He can "flip" the alignment of his target and then everyone between them also flips.
So if you and another good guy just stand on both sides of a demonified person, will they flip back?