From a roleplaying perspective, the human are the servants of the murderous, torturing scum that had their way with you for so long. Unspeakably evil demons. LOL you are a paladin, remember?
The Renaar are the (more or less) innocent victims whose world has been stolen by the aforementioned evil demon and his servants.
I do the quests that I must do for the servants of chaos, but none that hurt the Renaar (I don't take the book, for example). I do all the Renaar quests. I usually wipe out all the humans before leaving but that depends on my mood <smile> since the loot and xp really isn't worth the effort. I only do it for roleplaying reasons. Samuel will need a new logistics support base, not to mention a new general.