This is the qin race from Hyperconscious. A good fit for Dark Sun, perhaps?
*The qin are psionic humanoids who view other intelligent races as property by right of mind.
*The qin people have no plans for world conquest, and they usually ignore the political nuances of “lesser” creatures. Most are simply interested in collecting other races as slaves to make their own lives more comfortable.
The qin infiltrate human cities, and the practice of slavery prevalent on Athas is perfect for the qin. The qin have racial telepathy among their own people, so they can communicate with each other in secret. A slave holding aristocrat may actually be a qin. A templar may be a qin. A society within a society.