Mirror World

Mirror World is the world on the other side of the regular world. Mirror World is most notable for it's connection to Hades, the realm ruled by Elizabaoth. Certain people in the Mirror World can also use Persona.

Discovery
Irene discovered Mirror World one day by tripping into her mirror. Irene explored Mirror World and collected all of its effects. She eventually came into contact with Faceless, a murderous psychopath who tried to kill her. Irene and Madotsuki would eventually battle and defeat Faceless.

Connection to Hades
After the death of Faceless and Zalgo, the realm of Hades was unlocked. At seemingly random times, Madotsuki and Irene will be forced out of the real world into Hades for between 4-7 hours. They use this time that they are trapped in Hades to find out more information about Elizabaoth and Immensus.

Past
Mirror World was originally ruled by a wealthy and benevolent family. Of this family was Elise, the mirror version of Irene. Faceless would kill every member of this family so Zalgo could control both Silent Hill and Mirror World. One of the graves in Elise's manor mentions Madotsuki, meaning that Madotsuki's mirror version also died in Mirror World. It's possible that in order to wield Persona in Mirror World, the mirror variant has to die first.