(coexisting on another dimensional plane)
The mirror universe was a morally reversed or "mirrored" reality parallel to the Prime universe.
Sometime before 1783 the British Empire was founded and began to spread throughout Earth like a plauge, earning them the nickname Black Death, by 2063 they had conquered the entire world and had evolved into the Terran Empire.
Late 21st Century
On 5th April 2063, the Vulcan ship T'Plana-Hath landed in Bozeman, Montana where they encountered Zefram Cochrane who rallied the other Terrans to board the ship, kill all Vulcans inside and raid their technology.
The mirror universe had many different organizations.
- Terran Empire (Central government)
- Klingon-Cardassian Alliance
- Galactic Coalition
- Romulan Empire (replacement state)
- Xindi Council (mirror)