Good and evil are completely subjective. Villains don't see themselves as the bad guy, they see themselves as the only one that's right. After all even things like Genocide and Ethnic Cleansing are actual and constant events and I doubt the people committing them think themselves evil, merely that they're making the hard choice. You can argue whether a sociopath or extreme narcissist can be considered inherently evil and not everyone would agree or disagree. Same goes for the nature of good, just because a billionaire donates to a charity doesn't make them good it can also be viewed simply as their method of buying their way into a good afterlife. After all how did that billionaire even earn their money, how many lives did they ruin on their way to such wealth and how much harm did they cause in the long term. You can even argue the motives behind good actions, the guy who helps out at a local shelter is doing something good, but can be doing it simply because it makes them feel good. They're doing a good action but for a completely selfish reason. Good and evil, justice and revenge are concepts created and enforced by the community not natural concepts instilled in every human being.