I rarely ever outright hate characters, but I just... really really don't like Ashfur. He's not sympathetic, because his motives are so petty and overblown, and he's not really interesting as a villain because he doesn't do much and is too angsty to be genuinely entertaining. I just find him obnoxious because he doesn't even really reach love-to-hate status.
And like, I normally really like pathetic sad-sack characters, and one of my favourite types of villains are the ones who are completely lacking in self-awareness and insistent that they are the ones who have been wronged, but Ashfur is just... ugh.
I think a lot of it is the way the narrative wants you to feel about him. I'm still pissed that he went to StarClan and they went out of their way to defend him.