There's a game called Wildermyth where every faction is inherently incompatible with humans, but none of them are inherently evil.
For example, the Gorgons are an empire seeking to reclaim lost territory. This is fair, but they're aquatic, so they need to flood the world to take it back. Humans naturally need to fight them in order to survive, and there's no real way to compromise on that. It doesn't help that they ooze corruption everywhere they go.