Mirror Universe

A Mirror Universe is a common plot device in fantasy, horror and sci-fi which takes the idea of parallel-realities and mixes it with dark fiction to create dystopias in which the traditionally "good" portions of a series are replaced by "evil" or "corrupt" versions.

Like many concepts the Mirror Universe is a source of parody due to it being used so often and some authors do not like utilizing it as they feel it has become dated - regardless of this criticism it remains very popular and many large franchises have at least on "Mirror Universe".

Unlike "Bad Futures" most Mirror Universes are implied to have evolved alongside the mainstream universe rather than splitting away at a certain point in history, though exceptions exist.

Perhaps the most famous example of the name "Mirror Universe" comes from Star Trek, which also popularized the image of evil "twins" having beards (which was parodied mercilessly by varied media afterwards).

Ancient LegendsEdit
Despite the concept being associated with science fiction the idea of a Mirror Universe is very, very ancient and many cultures believed mirrors held "hidden" worlds within them - numerous superstitions surround mirrors and reflections, some of which deal with the concept of what modern writers would think of as "parallel universes" (explained via ancient minds as "magic" or "spirit worlds") Mirror World' - a warped, blurry, direction-reversed, demonic reality that is the fully reversed fully reversed version of the human world in the Devil May Cry'' universe and it is accessed via a mirror on Mallet Island. Its directions and structures are symmetrical to those in the real world: its sky shows beams of light returning into a crimson sun.
 * "Bizarro World" - a phrase commonly used to describe a situation that is at odds with what is considered normal reality, named after DC's tragic villain Bizarro - who had a "mirror" personality, seeing "good" and "evil" and so forth.
 * ''' The Mirror World
 * Mirror Universe (Star Trek) - (MU) (also referred in code as The Looking Glass) arguably the most famous of these universes and the one that most likely originated the term "Mirror Universe" (at least to the general public): for more information on this realm see Terran Empire and Klingon-Cardassian Alliance.
 * NegaVerse - In the Darkwing Duck episode "Life, the NegaVerse, and Everything", it was implied that NegaDuck came from this universe. The portal was inside a giant cake. The NegaVerse had a twisted, ruined version of St. Canard, filled with pollution and wrecked houses. Even the citizens had alternate personalities from Darkwing's St. Canard. While most of the Muddlefoots and Launchpad had insane, sadistic personalities, Gosalyn was a sweeter version as opposed to her tomboy personality, and Tank was intelligent and polite instead of being a bully. Even the Fearsome Five had friendlier versions of themselves, calling themselves the Friendly Four.
 * Wishverse - In Buffy the Vampire Slayer TV series, a scorned teen named Corderlia Chase unwittingly summoned a vengeance demon named Anyanka who granted wished to scorned women. She blamed Buffy Summers for her the bad turn her life went for if it wasn't for the fact she hung out with Xander Harris, she wouldn't have fallen for him and she would have not been hurt when she kissed Willow Rosenberg. So she wished that Buffy never came to Sunnydale and her wish was granted. In doing so, an alternate reality which Buffy went to Cleveland rather than Sunnydale was created. Here the town was taken over by The Master, a malevelont vampire master who rules a vampire cult called The Order of Orellius. Also serving as his two generals were this world's version of Willow and Xander.