Mirror universe

The mirror universe is a parallel universe where the patterns of events move in similar manners to that of the primary universe, but the intentions and characterizations are different, often showing "evil" characteristics in place of "good" and vice versa. The mirror universe shares a similar history to that of the primary universe and many of the same people exist in this reality, but they and the galaxy they live in are skewed versions of their "normal" counterparts.


 * Because of the development of the mirror universe in canon and non-canon works over the years several alternate mirror universes have been established. The page approaches the mirror universe from its most recent and complete canon version with compliant non-canon works, accepting variations of the mirror universe presented in other non-canon works as alternate mirror universes.

Early History
It is not clear if the mirror universe diverged from the primary universe at some point or always existed in tandem, mirroring events and peoples. If the two universes did diverge it was at a point many hundreds of years ago. $𝜇$ noted that the "great works" of literature in both universes were roughly the same except that the primary universe characters were "weak and compassionate," with the exception of that William Shakespeare and his $𝜇$. 


 * In the mirror universe of Dark Mirror, Earth's history took a darker turn starting with the end of Homer's Iliad, where Achilles kills King Priam instead of showing one moment of humanity. Khan Noonien Singh and the other supermen won the Eugenics Wars, but then wiped each other out. The Vulcans were also militaristic as there was no Surak.

The mirror Klingon culture has a basis of celebrating the victory of $𝜇$ over $𝜇$. 

On April 5, 2063, first contact between $𝜇$s and $𝜇$s took place much as it did in the primary universe. However, once the Vulcans landed, instead of welcoming them with open arms, $𝜇$ shot the first Vulcan to step onto Terran soil and the Terrans proceeded to raid the Vulcan ship, the $𝜇$. The gun used by Cochrane later would come into the possession of Commander $𝜇$, who wondered what would have happened had Cochrane not "turned the tables on [the Vulcans'] invasion force." With advanced Vulcan technology now at their disposal, the Terrans were able to expand the Terran Empire and conquer other worlds, including Vulcan. 
 * ''It is not clear when the Empire began. Archer once stated that the Empire had existed for "centuries" as of 2155. Archer did not mention how many centuries, but by his statement, the Empire can be traced back to at least 1955, suggesting that it was a Terran political unit before it became an interstellar empire. The credits sequence for In a Mirror, Darkly used footage of battles going back at least to the "Age of Sail". It also appears that it is the empire that conflicts with the Xindi.


 * In the Mirror Universe Trilogy First Contact was the point of divergence with the primary universe; at this point Zefram Cochrane warned the Vulcans about the Borg. Humans and Vulcans formed a militaristic alliance to wipe out the Borg, after which they became the Empire.


 * The Mirror Universe Saga had the Empire come about because the Romulans conquered Earth and enslaved humans for almost a decade. When Earth overthrew the Romulans it embarked on a program of conquest itself and became the Terran Empire.

The Bajorans and Trill had empires until they were conquered by Earth. 

The history of Ireland followed a similar course to its primary universe counterpart with respect to the country's numerous conflicts with Great Britain over the course of several centuries.

Hundreds of years prior to the 24th century, Kai $𝜇$ foresaw the conquest of $𝜇$ by the Terran Empire in 2255 and the suppression of the $𝜇$ which involved the killing of its priests and the destruction of its icons such as the Orbs of the Prophets. Consequently, he preserved a fragment, known as a paghvaram, from each of them. During his orb experience with the Orb of Souls, he made contact with his primary universe counterpart, who was likewise the Kai of Bajor, and one of the fragments was transported to that universe for safekeeping. This may have been the first direct contact between the two universes. The paghvaram was kept in the village of Sidau in Hedrikspool Province until it was stolen by Iliana Ghemor in 2376. 

22nd century
By the 22nd century with advanced Vulcan technology at their disposal, the Terran Empire had expanded and conquered other races, including the Vulcans, Andorians, Tellarites, Orions and Denobulans.

In 2155, the ISS, under the command of Captain Maximilian Forrest was the flagship of the Terran Empire's $𝜇$. In January of that year, Commander Jonathan Archer mutinied against Forrest in order to take the ship into Tholian space to capture the primary universe starship USS Defiant (NCC-1764) which the Tholians had obtained. While the mutiny was ultimately unsuccessful, Captain Forrest had no choice but to continue the mission, since the ship's helm had been locked on auto-pilot. The Enterprise was later destroyed by Tholian ships, but not before Archer was able to take control of the Defiant. Archer tried to use the Defiant in a grab for power, intending to replace the Emperor, but was betrayed and killed by $𝜇$, who declared herself Empress. 
 * Sato's rise to power is detailed in Age of the Empress.

23rd century
In possession of the USS Defiant the mirror universe was aware of the primary universe. In the primary universe, Section 31 had some knowledge of the mirror universe. 

However it was not until 2267 that any official contact between the universes is recorded. By this time the Terran Empire was the dominant power in the Alpha Quadrant. In a transporter accident caused by interference from an ion storm a landing party from the USS Enterprise (NCC-1701) switched places with an identical party from the ISS in the mirror universe. The four Starfleet officers; Captain James T. Kirk, Lieutenant Uhura, Lieutenant Commander Montgomery Scott and Doctor Leonard McCoy found the terran vessel to be brutal regime, almost dictatorial in its command structure. Advancement through assassination was commonplace.

During the encounter, Captain James T. Kirk convinced the counterpart of his first officer, $𝜇$, that the Empire could not sustain itself. Indeed, Spock predicted that in its current form, the Empire had just over two centuries before total collapse. 

Shortly thereafter, Spock rose to become leader of the Terran Empire, proposing a series of reforms designed to make the Empire more secure and less dictatorial in nature. These included a significant disarmament program. Unfortunately, once these reforms were complete, the Empire was unable to defend itself against the equally aggressive and powerful forces surrounding it. The Klingon-Cardassian Alliance overran the Empire, conquering Earth and leaving Terrans and Vulcans enslaved. 
 * Spock's rise to power is detailed in The Sorrows of Empire.

During this time, the forces of the mirror universe began implementing safeguards to prevent another crossover event with the primary universe. Transporter design was altered to prevent interdimensional travel, requiring the creation of devices specifically for that purpose, including the multidimensional transporter. In the event of another crossover, those involved would be killed to prevent further interference. 

In 2293, after being snared in the Janus Prime Vortex, Captain Hikaru Sulu and the crew of the USS Excelsior (NCC-2000) found themselves in the mirror universe, transposed into the bodies of their duplicates, aboard the ISS. In order to return to their own universe, Sulu's crew were forced to use the Imperial starship and its fighters to escape from the Terran Empire, and enlist the aid of the Klingon Alliance and the Romulan Republic in fighting the Tholian Empire to gain access to the Janus Ultima Vortex. 

24th century
By the early 24th century the Terrans had been reduced to a slave race and a handful of rebels on the run from the Klingon-Cardassian Alliance, which was intent on destroying the entire Terran race. One such ships used by the Terran Rebellion was Stargazer, captained by $𝜇$. 

$𝜇$, formally occupied by the Terrans was freed by the Alliance and soon joined it, in orbit the command post/ore processing facility Terok Nor was constructed.

By 2370, the second major contact with the primary universe took place. A runabout from station Deep Space 9 entered the mirror universe following an incident in the Bajoran wormhole. Kira Nerys and Julian Bashir were captured by forces from Terok Nor, and interrogated by the commander, Intendant $𝜇$. Bashir was sent to work in the ore processing plant, where he befriended $𝜇$. After instigating a series of incidents aboard the station, including the death of $𝜇$ during a slave uprising, Kira and Bashir convinced privateer $𝜇$ to rebel against the Alliance and help them to escape back to the primary universe. 

A year later, Smiley crossed over to the primary universe and impersonated his counterpart long enough to capture Benjamin Sisko. He took Sisko back to the mirror universe, where he convinced him to impersonate his mirror self who had been killed in a skirmish with Alliance ships. The rebels needed the other Sisko to win over $𝜇$, Sisko's wife, who was working as a scientist for the Alliance. Jennifer had been developing a transpectral sensor array which would have allowed the Alliance to locate rebel hideouts in the Badlands. Fortunately for the rebels Ben was able to convince Jennifer to defect to the rebels. 

In the Badlands, $𝜇$, a former slave, commanded a ship in the rebellion attempting to evade pursuit. There he encountered a strange ship which had been catapulted seventy thousand light-years across the galaxy. 

While in the Federation's universe, Smiley downloaded information from Deep Space 9's computers, including the plans for the USS Defiant (NX-74205) (I). In 2372, the rebels constructed their own version of the $𝜇$, but had trouble getting it to function properly. Jennifer lured Ben Sisko back into the mirror universe to help. By this time the rebellion had grown in strength, culminating in the capture of Terok Nor, which became a rebel base of operations. 

In 2374, Intendant Kira sent a thief, $𝜇$ to the primary universe to steal one of the Bajoran Orbs, believing it would permit Kira to unite Bajor under her rule. The attempt failed, and Bareil returned to the mirror universe without the orb. 

In 2375, Grand Nagus Zek, the leader of the Ferengi Alliance in the primary universe, used the multidimensional transporter to travel to the mirror universe, hoping to open up business opportunities, however he was captured and held hostage by the Alliance. Intendant Kira made arrangements with $𝜇$, the Regent of the Alliance, to obtain a Klingon cloaking device from the primary universe in exchange for Zek's return.

She sent $𝜇$, a Trill mercenary and Kira's lover, to give Quark the ransom demand. Quark and his brother Rom stole the cloaking device from Klingon General Martok's ship and delivered it to Ezri, but decided at the last minute that they couldn't trust her to keep her side of the deal, and accompanied her to the mirror universe. There all three were captured by the Terran rebels, who planned to keep the cloaking device. Ezri's companion $𝜇$ freed them, delivering them to Regent Worf. Aboard Worf's flagship, Quark and Rom were imprisoned along with Zek upon discovering Kira's plan, only to be later rescued by Ezri as revenge against Kira for killing Brunt. Ezri ended up joining the rebel cause. The primary universe Ferengi were allowed to return to the primary universe for having aided the rebels' defeat of Worf, a major victory for the rebellion. 


 * Continuing events on the mirror universe are told in Saturn's Children.

In late 2376, Intendant Kira managed to use a form of mind control to manipulate the primary universe Jem'Hadar Taran'atar into doing her bidding. She had him attack Kira Nerys before fleeing Deep Space Nine and eventually beamed him into the mirror universe, shortly after she was killed by Iliana Ghemor. 


 * The continuing tale of events in the mirror universe are told in the novels Fearful Symmetry and The Soul Key.

From 2376 onto 2381, after the fall of Terok Nor to the Cardassians, the Terran Rebellion united with the Mackenzie Calhoun and the remnants of the Romulan Empire along with the forces of Memory Omega with Jean Luc Picard as their leader to liberate Earth, where they then proceeded to liberate other core worlds of the Terran Empire. Instigating a war between the Klingons and the Cardassians, the Rebellion was able to sue for peace and create the Galactic Commonwealth, a representative republic that was in the process of rebuilding its member worlds. 

25th century
By the 25th century, the Terran Rebellion had succeeded in throwing off Alliance rule and a restored Terran Empire was once again a major power in the quadrant, possessing technology and weapons roughly on par with 25th century Starfleet in the primary universe. Terran Empire ships and forces have been known to operate in and around Cardassian territory, and even conduct missions to use the Bajoran wormhole to infiltrate the counterpart universe. (Star Trek Online)

Technology

 * agonizer
 * agony booth
 * multidimensional transporter device
 * tantalus field
 * tricobalt warhead

Background
The mirror universe was first established in the episode "Mirror, Mirror;" following this there were no further canon visits until the Deep Space Nine episode "Crossover." DS9 continued to explore the mirror universe in several episodes and some year later the series Enterprise also explored the mirror universe in "In a Mirror, Darkly". Between these various canon productions the mirror universe was the basis of many novels and comics; however as each TV series made its own mark on the continuity of the mirror universe the histories and futures established for the universe in non-canon works began to contradict canon. Most recently several mirror universe novels have been published in the DS9 Relaunch series and the Star Trek: Mirror Universe series which integrate new non-canon stories into the complete canon mirror universe.

Episodes

 * ENT: "In a Mirror, Darkly"
 * TOS: "Mirror, Mirror"
 * DS9:
 * "Crossover"
 * "Through the Looking Glass"
 * "Shattered Mirror"
 * "Resurrection"
 * "The Emperor's New Cloak"

Novels

 * Glass Empires
 * Age of the Empress
 * The Sorrows of Empire
 * The Worst of Both Worlds
 * Obsidian Alliances
 * The Mirror-Scaled Serpent
 * Cutting Ties
 * Saturn's Children
 * Shards and Shadows
 * Nobunaga
 * Ill Winds
 * The Greater Good
 * The Black Flag
 * The Traitor
 * The Sacred Chalice
 * Bitter Fruit
 * Family Matters
 * Homecoming
 * A Terrible Beauty
 * Empathy
 * For Want of a Nail
 * The Sorrows of Empire
 * Rise Like Lions
 * Three
 * Warpath
 * Fearful Symmetry
 * The Soul Key

Other stories of the Mirror Universe outside primary continuity.


 * Mirror Universe Trilogy by William Shatner:
 * Spectre
 * Dark Victory


 * Dark Mirror
 * Dark Passions
 * Millennium: The War of the Prophets

Comics

 * TOS:
 * "Fragile Glass"
 * The Mirror Universe Saga
 * Mirror Images
 * DS9: "Enemies & Allies"

Other licensed works

 * Through a Glass, Darkly is an RPG that focuses on the mirror universe.
 * Two video games incorporate mirror universe elements: Shattered Universe and .
 * Several expansions of Star Trek CCG make use of the mirror universe, chief among them Mirror, Mirror and In a Mirror, Darkly.
 * Star Trek Encyclopedia provides information on mirror universe characters and storyline.
 * Star Trek Chronology and Voyages of Imagination place mirror universe events into a timeline.