Liath

The race of grey dwarves, most of which now live in cities deep in the Underdark, though some have adapted to life on the surface.  These vicious, stealthy slave traders raid the surface world for captives, then sell their prey to the other races of the Underdark or surface slavers. It is rumored they have innate magical abilities to become invisible and temporarily grow to giant size.
Not much is known how these once peace-loving dwarves descended into the darkness to fracture from the surface dwarves.  It is known they only adhere to three tenets: our pockets are never full, our fight is never done, and our resolve is never shaken.