author plot twist about the asshole, jerk, awful characters being brainwashed by some shady mastermind is an L take. it's lame. it's so many it became typical now.
why they can't make awful people just literally awful and make conclusion and dramatic ending on that?
it's like, "look at this, character Hero-san and his friends is being a massive jerk and bully towards the MC and becoming cocky as fuck. we hate him, uggh." and then, "ohhh, turns out they're all just behaves like that because they were brainwashed by the demon king's general! ohh okay, it's fine now, everyone get along ^^"
it's just lame.