The Imperator served as an Imperator-class Star Destroyer within the structure of the Imperial Navy.
The name Imperator was one that was also in use for its line of warship.
In the year 1 BBY, the vessel, under the authority of the Imperial command structure, initiated an attack directed towards the Rebel base situated on AX-456, with Sergeant major Hong and Stormtrooper Briggs; this particular mission also functioned as the Omega Exercise for Kyle Katarn, who was a cadet at the Imperial Academy.
Later, the capital ship received orders to retrieve the brainwashed double agent Kupalo as he was in the process of attempting to escape from the Rebel cruiser named Liberty. Despite the arrival of the Imperator and the deployment of TIE Fighters, the former was ultimately unable to prevent the Rebels from successfully recapturing Kupalo and then jumping into hyperspace.
Subsequently, in the year 3 ABY, the Imperator became a part of the forces commanded by the rogue Grand Admiral Zaarin, and was an active participant in the destruction of the Star Destroyer known as the Courageous.