Terran Empire

The Terran Empire is, in fictional universe of Star Trek, an alternate-history counterpart of the United Federation of Planets. It appears to differ from the Federation in almost all ways---where the Federation is peaceful, the Empire is violent to the point of allowing promotion in its Starfleet via assassination of superiors; where the Federation has strict rules protecting less-advanced societies, the Prime Order of the Empire is to allow no resistance to its wishes to go unpunished. Punishment on Imperial Starfleet vessels is administered by the use of hand-held "agonizers," or, for serious offenses such as an unsuccessful assassination of a superior, the "agony booth." Both of these work by direct stimulus of the brain's pain centers. Aliens are experimented on in painful ways as a matter of routine.

The uniforms and heraldry of the Empire reflect its very violent nature; uniforms are more flamboyant and often blatantly sexually suggestive, and always incorporate weapons---daggers and phasers. The symbol of the Empire is a stylized Earth with a sword behind it, the hilt appearing to protrude from the North Pole and the point coming out behind the South Pole.

The Empire is stated to be unstable in the episode in which it appears (Mirror Mirror) and the mirror-universe Mr. Spock estimates that it will be overthrown, violently, in the next few centuries. In contacts with what appear to be that alternate history in later Star Trek series, this appears to have taken place. In the Star Trek: Deep Space Nine episode Crossover we discover that it feel to an alliance of Klingons and Cardassians, and Humans and Vulcans are now enslaved.