The key thing to understand about pulling characters from games, or any fiction, is that it’s an art. You need a good AI to even have a chance, and then you need a lot of human input. First you map all decisions, conversations, and actions a character made onto a blank AI matrix. You are mapping out what is basically a life. And since many characters make different choices based on what you do in the game, you have to factor that in as well. Sometimes you have to add extra life choices, or massage existing choices when they conflict with the pattern you are trying to model. What you want is a basic AI that will make the same choices as the source character while being capable of operating in an open environment. That is not easy.