Xerxian

Xerxian was an individual of Human or Sith pureblood descent who held the title of Moff of the reconstituted Sith Empire. Xerxian was assigned to govern the planet Sullust sometime after it was captured by the Empire during the Great Galactic War with the Galactic Republic, but when Xerxian failed to put down a violent uprising among the native Sullustans sometime between 3681 and 3640 BBY, he was summoned to a private audience with Darth Marr, a member of the Empire's ruling Dark Council.

After the meeting with the Sith Lord, Xerxian dictated a letter of resignation and shot himself, leaving many to believe that Marr had removed his mask and allowed Xerxian to view his supposedly ruined visage, thereby driving the man insane.

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