If I designed the NWN 1 story line I would not have used the Creator Races at all. Ancient evil equals lame. Been there done that, who gives a smeg. I would have used a brand new evil. An evil so new that they have only been in the Realms maybe 12 to 14 years.
The Kir-Lanan Gargoyles. Born from the corrupted energies of the dead gods Bane, Myrkul, and Bhaal they seek to destroy all the gods and their "godslaves." A particularly strong leader could form a coven that could implement the Wailing Death which it decays and kills the soul of the inflicted and tranfers that spiritual energy to lead Kir-Lanan. They would use trickery to lure some of the godslaves to do their bidding but inthe end would kill them just as well.
Hmmm...
Also I would have it that the PC or PCs could actually get the Wailing Death disease and have it drain the character's stats as time goes along. I mean, you need to find the cure not to save the city but to keep your own arse alive. It wouldn't be automatic but would require a Fortitude Save in the right circumstances.
I am beginning to like this idea...