In the mirror universe, the Imperator-class was a prototype four-warp nacelled dreadnought starship of the Imperial Starfleet of the Terran Empire in the 22nd century. The most powerful warship built by the Terran Empire, the ISS Imperator was the first and last ship of its class, as rebel forces attacked the Antares shipyards shortly after the ship's launch. It had been intended as the new flagship, but was deemed "too big and too ugly" by the Emperor. (ENT - Mirror Universe novel: Age of the Empress)