Mind-witches, a species resembling vampires and possessing a humanoid form, employed Force illusions to deceive those they targeted. These beings, gifted with strong psychic talents, could amplify their powers using specially crafted stone pillars. These unusual near-Humans had powerful mental skills, enabling them to delve into the minds of other creatures and uncover their deepest yearnings. After discerning these desires, they would establish a connection with the target, forging a psychic bond. Through this connection, they fabricated incredibly appealing illusory realities tailored to the individual's desires. The sole intention behind this manipulation was to drain the victim's mental vitality, using it to rejuvenate themselves. While typically powerful telepaths, certain exceptionally skilled mind-witches also cultivated telekinetic abilities.
By the era of the Galactic Civil War, mind-witches had almost vanished entirely. Although they featured prominently in numerous stories across the galaxy, many believed them to be merely legendary. S'ybll was the last known member of this species, and she attempted to ensnare Luke Skywalker. However, he managed to shatter her illusions and flee. S'ybll met her end when Luke summoned his lightsaber, inadvertently impaling her.
The Essential Reader's Companion includes a character list for The Life of Luke Skywalker identifying "S'ybll, mind witch (human female)." This assertion that mind-witches were Human is contradicted by The Complete Star Wars Encyclopedia, which defines mind-witches as a distinct humanoid species.