The Mirror Dimension is a parallel dimension that allows the user to practice their magical abilities and fight their enemies without the public's knowledge. Those who use the power of the Dark Dimension have a stronger control over space and matter than they usually would, to the point of being able to fold and warp space in reality.
- 1 Overview
- 2 History
- 3 Trivia
- 4 External Links
- 5 References
The Mirror Dimension allows an advanced sorcerer to train more advanced and dangerous spells without adversely affecting the real world, keep an eye on threats without being noticed, and a prison for those without a Sling Ring. The final usage is paramount that a prisoner is locked without a Sling Ring as it is the only means to escape. However, the realm is shown to be accessible without the use of the Sling Ring, which allowed the likes of the Ancient One and Doctor Strange to transport themselves and others into the dimension, though a Sling Ring was ultimately required to leave it.
In addition, the Mirror Dimension can be used in combat by a sorcerer with the knowledge and skill needed to perform it liberally by manifesting a gateway to it to absorb attacks and then sending the manifestation at the enemy to trap them at the Mirror Dimension, but these Mirror Dimension gateways can seemingly be destroyed when enough power is directed at them, as Thanos was able to use the Power Stone to destroy a gateway that was sent towards him by Doctor Strange.
After stealing a page from the Book of Cagliostro, Kaecilius and his followers, the Zealots, escaped through a portal to London with the Ancient One in pursuit. The Ancient One proceeded to send them to the Mirror Dimension to remove the danger they presented to the real world. In the resulting battle, several Zealots were killed by the warped landscape but Kaecilius managed to open a portal and escape with the page. The Ancient One exited the Mirror Dimension and reentered London.
Training Doctor Strange
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After the initial attack on the New York Sanctum, Doctor Strange trapped all of them inside the Mirror Dimension just before Kaecilius was about to destroy the place. Karl Mordo informed Strange that the Zealots' connection to the Dark Dimension made them even stronger in the Mirror Dimension. Realizing that their plan backfired, Mordo and Strange tried to escape. However, Kaecilius made their escape harder for them by warping reality to the point where navigation became very difficult.
Trapped Between Two Worlds
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In 2018, while on the planet Titan, Doctor Strange opened a gateway to the Mirror Dimension to protect himself against an energy blast from the Power Stone unleashed by Thanos and then sent the gateway at Thanos in order to trap him in the Dimension only for Thanos to shatter the dimensional gate via the Power Stone before using the Space Stone to collapse the remnants into a destructive black hole that he threw at Strange.
To be added
After Stephen Strange resurrected Christine Palmer, his universe began to collapse and Strange struggled to hold it back, Strange begged The Watcher, whom he had noticed earlier, to help him fix back his universe and punish him instead, but the Watcher refused, stating that "meddling with time and events only leads to more destruction", shortly after leaving, Strange's universe entirely collapsed, saved for a reality bubble composed of the remains of the Mirror Dimension held together by Strange's magic, as Palmer faded away in his arms questioning what he had done, Strange sobbed and apologized, left alone as the last survivor of his home universe.
Visited by The Watcher
The Watcher later ended up in Strange's pocket dimension after escaping his battle against Ultron. With the Multiverse in peril, the Watcher reluctantly decided to break his non-interference oath to request Strange's assistance against Ultron.
Strange later returned to the Mirror Dimension with the Watcher. While holding a miniaturized pocket dimension containing Killmonger, Arnim Zola and the Infinity Stones, Strange remarked that the Watcher had foreseen everything in the Guardians of the Multiverse's battle, from the failed Infinity Crusher to Killmonger's betrayal. The Watcher added he also foresaw Strange sacrificing himself to guard the imprisoned villains to keep them from escaping, a task Strange agreed to undertake. 
- The Mirror Dimension was influenced by the works of mathematical painter M.C. Escher and the fractal concept.