Calrax the Destroyer

Calrax the Destroyer or simply Calrax, or formerly known as Herax, was a hybrid of Celestial/Demon DNA. A warlord from the Shadow Dimension, Calrax was a fierce, deadly warrior and cunning leadership skills caught the eye of the "Great One", who recruited him to act as the official head of the Dominion of Empires. He managed to gain control of a majority of the galaxies that belong to the Alliance of Empires. He vastly reduced their numbers to a mere millions in a matter of days, and quickly subdue the Imperial Remnant, New Confederacy in a prolong siege against them. He also managed to kill Emperor Odios, while simultaneously ordering the death of Grand Admiral Thrawn.