Darth Vader

Darth Vader was a Sith and a leader of a group of Sith who were politically independent of the Sith Empire. Vader and his group of Sith soldiers served the Sith Empire, the Imperial Republic, and other governments as hired mercenaries.

During the reign of Anakin Skywalker, Darth Vader's mercenaries were hired to fight the Rebel Alliance along with the warships of the Imperial Navy and the Imperial Army stormtroopers.