Dark side adherents

Three Human dark side adherents operated on the moon Kalakar Six. They claimed to have uncovered secret knowledge of the dark side of the Force that was otherwise only known to Emperor Palpatine and his Sith Apprentice Darth Vader. The adherents believed that a remnant of the light remained within Vader from his time as the Jedi Anakin Skywalker, and so they sought to eliminate him by either resurrecting, cloning or conjuring a vision of Palpatine's former apprentice Darth Maul.

In 0 BBY, the adherents lured Vader to Kalakar Six through false information regarding the recently stolen plans for the Galactic Empire's Death Star. Vader travelled to the moon, where the adherents and Maul dispatched his stormtroopers. Inside a fortress, the adherents revealed themselves and challenged Vader's loyalty to the Sith. Maul duelled Vader and lost when the latter Sith impaled himself with his own lightsaber to kill Maul. The adherents were shocked at their loss, and were then killed by Palpatine, who had abruptly arrived.

Text and facts from the “Dark side adherents” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.