Existing within an expansive multiverse, the Prime Universe, containing interstellar powers
like the United Federation of Planets and Klingon Empire, shared a special relationship
with what became known as the Mirror Universe.
An alternate reality existing on the same plane but a different dimension, sharing many
similarities in their history and population, though specific details and personalities
were often different.
Among the few known fundamental differences, was that beings from the mirror universe were
more sensitive to bright lights.
Though the human civilizations of Prime Earth fought wars and committed terrible atrocities
against each other, many individuals were able to retain good natured and trusting personalities.
This however was not the case with most humans of the Mirror Universe, as they were raised
in a cut-throat, fascist culture spread by the Terran Empire, which over time grew it’s
influence across the entire world.
Ruled by the absolute authority of an Emperor, Terrans believed life was a constant struggle
for survival and everyone was out for themselves.
They lied, cheated, stole and killed if it was to their benefit, with assassination eventually
becoming a common form of career advancement.
Just like in the Prime Universe, Mirror Earth experienced first contact with the Vulcan
species in 2063.
However with a paranoid, militaristic culture taking hold in many parts of the world, Zefram
Cochrane did not make peaceful contact with a Vulcan representative, instead feigning
civility before pulling out a shot gun to kill the alien.
An incident remembered in their history as the defeat of a Vulcan invasion force.
After the initial attack, Cochrane’s followers then stormed the Vulcan ship and harvested
its technology, using it to advance and unite the human race under the authority of the
Terran Empire.
Growing into an interstellar power, they conquered vast portions of the Alpha and Beta quadrants,
enslaving species like the Vulcans, Andorians, Tellarites, Orions, Denobulans, Kaminar and
Kelpians and Klingons, some of whom were founding members of the Federation in the Prime Universe.
In 2155, as the Terran Empire fought to suppress a rising rebellion, First Officer Jonathan
Archer mutinied against his Captain Maximilian Forrest aboard the ISS Enterprise, taking
command to ensure they completed an unsanctioned mission of his own design, learning about
an advanced star ship called the USS Defiant located in Tholian space, transported from
the Prime Universe, a century in the future.
This was also the first time they learned about an alternate dimension with a special
connection to their reality.
Though Forrest eventually took back control of the Enterprise, Archer sent his plans to
their superiors who agreed with it’s potential, ordering the Captain to release Archer and
continue on their present course.
Leading the mission to board the Defiant, Archer found the Starfleet crew dead, and
so took control of the ship.
Meanwhile, the Tholians attacked and destroyed the Enterprise for violating their space.
Though most of the crew fled in time, Captain Forrest went down with the ship, buying them
as much time as possible to escape.
Archer was then free to take command of the Defiant, planning to use its advanced technology
to overthrow the Emperor, but in the end was betrayed by Hoshi Sato, the former lover of
Forrest who renewed an old relationship with the Captain to bide her time, before killing
Archer, taking command of the Defiant and using it become Empress of the Terran Empire.
A century later in the 2250s, the Terran officer Gabriel Lorca attempted to overthrow Empress
Philippa Georgiou, and so she sent her adopted daughter Michael Burnam to track down the
rebel leader, only for her to join in his rebellion.
Yet Burnam was ultimately killed and Lorca nearly captured, causing him to transport
during an ion storm, leading to a malfunction which switched him with his Prime universe
counterpart.
Impersonating Starfleet’s Gabriel Lorca, the Terran took command of the USS Discovery
in 2256, using its spore drive to transport back to the Mirror Universe where he once
against attempted to overthrow the Empress.
But when Prime Michael Burnam learned the truth about Lorca, she allied with Philippa
Georgiou to defeat the rebellion.
In the end Lorca was killed and the Empress transported to the Discovery before it returned
to the Prime Universe in 2257.
Stuck in an alternate reality, Georgiou eventually went to work for the rogue espionage agency
section 31.
Learning of the Mirror Universe for the first time, the Federation classified the information,
keeping it from becoming public knowledge.
A decade later in 2267, 4 Prime Universe crew members aboard the USS Enterprise switched
places with their Mirror Universe counter-parts due to yet another transporter malfunction
during an Ion storm.
Though both groups eventually made their way back to their own realities, Captain James
Kirk used his time in the Mirror Universe to speak with Mirror Spock, using logic to
convince him the Terran Empire was doomed to collapse in the next few centuries, thus
he must find a way to change their culture and form of government, in the hope of creating
a more stable, long lasting state.
Inspired by this encounter, Mirror Spock grew his influence until he eventually became Emperor,
instituting reforms to make the Empire less authoritarian and militaristic.
However, their centuries of ruthless expansion and enslavement of conquered peoples meant
Terrans were surrounded and infiltrated by enemies like the Klingon-Cardassian Alliance
which took advantage of their weakening security to conquer the Terran Empire, enslaving and
subjugating humanity the same way they treated others for so many years.
In 2370, Bajor’s Kira Nerys and Starfleet’s Julian Bashir were transported to the Mirror
Universe due to a warpfield malfunction while entering the Bajoran Wormhole.
Finding Deep Space Nine, called Terrok Nor, under the command of Mirror Intendant Kira
Nerys, as Bajor joined the Klingon-Cardassian Alliance after suffering years on enslavement
under the Terran Empire.
Eventually Prime Kira and Julian ran into privateer Benjamin Sisko, convincing him to
start a Terran rebellion against the Alliance.
Making it back to the Prime Universe, they were followed a year later by the rebel agent
Smiley O’Brien, who captured Benjamin Sisko and brought him back to the Mirror Universe,
explaining that their Sisko, leader of the rebellion was dead, so they needed Prime Sisko
to take his place on a crucial mission.
Agreeing to help them, Sisko met with his deceased wife’s Mirror counter-part Jennifer
Sisko, a scientist working on a transpectral sensor array for the alliance, and convinced
her to switch sides.
Sisko was then returned to his reality until 2372, when they once again brought him to
the Mirror Universe so he might help the rebels build their own version of the Defiant.
Although Jennifer Sisko was killed, the Terrans managed to capture Terrok Nor, which became
headquarters to the rebellion.
In 2374, the dangerous and erratic Kira Nerys of the Mirror Universe launched a failed attempt
to steal Bajor’s sacred orbs from the Prime Universe, hoping to use them to become ruler
of her homeworld.
Refusing to give up on her aspirations for power, Kira’s next scheme centred around
the prime universes Grand Negus Zek, leader of the Ferengi Alliance, who in 2375 unwisely
transported himself to the Mirror Universe in the hope of finding new opportunities for
trade and profit.
Quickly captured by the Alliance, Kira convinced Regent Worf, to extract a ransom for the Grand
Nagus, arranging for the Ferengi Quark and Rom of the Prime Universe to steal and bring
them a Klingon cloaking device.
Yet Mirror Kira was betrayed by her lover Ezri, who helped free the Ferengi and joined
the Rebellion, leading to the death of Regent Worf, striking a critical blow against
the Alliance.