The brutal, expansionist state that rules much of the Mirror Universe, where humans conquer and enslave other species and officers advance through assassination.
The Terran Empire is the dark counterpart of the United Federation of Planets in the parallel Mirror Universe. Founded on conquest rather than cooperation, it subjugates alien worlds, demands tribute under threat of annihilation, and rewards ambition and treachery. Its starships carry the ISS prefix, and officers routinely murder their superiors to rise in rank.
Captain Kirk and members of his crew were accidentally swapped with their counterparts in 2267, finding an ISS Enterprise preparing to destroy the Halkans for refusing to surrender their dilithium. Kirk urged the mirror Spock to consider the Empire's inevitable fall and work to change it. Earlier history was shown in Enterprise, where the ISS Enterprise of the 22nd century seized a futuristic Federation starship from the Tholians.
In Discovery, Philippa Georgiou's mirror counterpart ruled as Emperor, and Gabriel Lorca was revealed to be a Terran exile. By the 24th century the Empire had collapsed, and the Klingon-Cardassian Alliance had conquered and enslaved humanity.