Emperor's Hound was the nickname of Bellatrix La Rouge when she served under Emperor Luthor Elyurius. It was later used as an epithet for two agents of the New Sith Imperium after the Purge: Geist Weiss and Arch'aza'cnuruodo; it was generally used to indicate Sith who were at Sith Lord level but were not officially Sith Lords.