Sacred Haven of Debauchery

Um... I understand what "eliminate all enemies" means. But I don't understand what "good roleplaying" or "a character that isn't too contradictory" means.

Yeah, I get your point now.
Imagine you're playing a game, and you're given a main quest. Some guy gives it to you. Let's say, "save the world." You go and try to complete it, meaning you save the world. Along the way, you visit locations, find allies, fight, complete side quests, and so on.
Now imagine that in this scenario, you don't have a guy giving you the main quest. There just isn't one. There are plenty of side quests, but no one has given you a main quest. How is that possible? And how can you build a game around that? It's very simple: you give yourself the main quest. The guy who gives the main quest and the hero are combined into one person. And what principle do you use to give yourself these quests? Obviously, the same principle that the guy used before, because he doesn't come up with them on the fly. The plot, the biography. To some extent, the character's personality, which compels him to pursue this particular goal and not another.
If simplified, that's how it works.