The Khadim were an endangered species. They had flat heads, three legs and two arms. They fled their homeworld in an attempt to escape the U'lanna civil war.
They were saved from extinction when the Stoneship rescued, and towed, the sleeper ship Kishuna. The Lyran Starfleet Command decided to relocate the survivors to Montrosa. (Star Trek: The Stoneship Files: "Generational Ghosts")