In the mirror universe, Kelvar Leonard Garth (2208-2269), better known as Garth of Izar, was the Grand Admiral of the Imperial Starfleet of the Terran Empire in 2269. His victory at the Battle of Axanar was one of the most famous in the history of the Empire. Garth's successor as Grand Admiral was Matthew Decker of the ISS Constellation, who served in that position until being killed by Spock in 2277. (TOS - Mirror Universe novel: The Sorrows of Empire)