I'm trying to find a nice detail'd guide for how NPC's AI and Faction works, I've never touched NPC's and would like to learn, but I can't find anything as detail'd as I'd like.

Have you gone through the tutorials at geck.gamesas.com? This gives some basics about using NPC's. Once you have these basics, either (a) you can make progress on your own, or (B) you will be able to post some more specific questions.