I'm not sure if this has ever been asked before but while wonder about such NC as the WOTGS and certain quests in Verbonnoc it occurred to me- what's the motavation for an evil party to do some of these quests? I realize there are a few that tends towards more evil alignments than others (the joining the assassins quest given to you by Romeg and Davos for example). But really- why would an evil party do some of these quests, like finding the Slavers? Wouldn't they be more likely to join the Slavers- or maybe take their place/positions after killing them? Basically what I'm asking is there a way to mod this game to give a more evil perspective, i.e. viewpoint so as to give the 'bad' guys some reason other than mass chaos, death and destruction to do these quests (not that there's anything WRONG with that- from an evil perspective...).
I find this kind of amusing, just a short while back another person posted as to why is all the NC made for evil parties. In my opinion, a great deal of the Verbobonc content IS aimed slightly more to the evil, (or at least Chaotic) parties. I can't answer your question very well because I'm yet to make it all the way through with an evil party.
Hmm haven't tried an evil party since WotGS. Having a hill giant and a succubus in the group should be delicious muahaha.