I guess it's a question of perspective like I wiped out a bunch of bed bugs and I guess I'd be the evil destroyer from the bed bug perspective?

There is a reason why in Christianity you can "repent". In the middle ages you could even pay for a get out of hell card.

Certain serial killers maybe? I get that people are fascinated by them, but to me such people are oddly boring. Their crimes are horrific, but the justifications (if not outright delusional) seem to be just "I can do whatever I want if I find a way to get away with it".

Most other people we might consider 'evil' have more moralistic justifications - such as religious fanaticism, or nationalism, or revenge against some perceived enemy. Not that this makes them right in absolute terms, but presumably they do not consider themselves evil.

yes, they're called sadists

I guess it depends on what you mean by "aware". Does awareness imply that someone simply knows that what they did was immoral, or does it also imply remorse? Psychopaths know that their actions are immoral but are incapable of feeling remorse.