The Sarnaks, a race which was created by the meddling of the Iksar Necromancers are in an ongoing state of war with the Legion of Cabilis (the Trooper Guards).
They have a fortress at the Lake of Ill Omen, as well as their ancestral home - the city of Chardok - which is within the burning woods.
Sarnaks are highly intelligent, and have a strong presense of magic users within their ranks.
Their warrior classes also tend to have a high magical resistance rate.
To my knowledge, there is nothing you can do to gain faction with Sarnaks.