Igor sending you here
The Shadow Realm (known by too many names) is a place where gods come and go to do evil things that directly effect the UnUniverse. Igor is the guy who always just so happens who decided to live here exclusively. This place has a past for bad people abusing it to do bad things.
After a god decides he or she wants to take it over, they consult King Frost to get Shadow Juice, Jack and Black Frosts. After an agreement is made and money switches hands, the mirror humans become shadows. However a side effect of Shadow Juice is that one good shadow always emerges that assists in the god's downfall. Then eventually the god tries to play a game with humans in the UnUniverse, this leads to the god's downfall and "The Collapse" of The Shadow Realm going back to a mirror of the UnUniverse instead of a corrupted version of it. In this event of the collapse, King Frost recoups his frost minions before the collapse kills them, and the time between when someone rules the place is when he sets up more Cadbury factories.
Incarnations of The Shadow Realm[]
Incarnation No. 0 - "The Sacred Realm"[]
Back before any of this nonsense happened this place was nice place, and the Triforce was kept here, it is written Bob Ross lived here for over just over 30,000 millennia before things went south.
Incarnation No. 1 - "The Dark World"[]
Ganon was sealed in this place and it got used for EEEVIL! Link killed him and this place was forgotten about for some amount of time. Not to be confused with Dark UnWorlds.
Incarnation No. 2 - "King Frost's Pocket Dimension"[]
Unknown how he used this place, probably is the guy who discovered how to fully utilize this place's full power. Near this time Igor would move in, unknown if King Frost was related to this or not.
Incarnation No. 3 - "Other Side"[]
Philemon would seal some bad timeline here and hope nobody would remember it. He did such a good job at it even I don't remember what it was about!
Incarnation No. 4 - "The TV World"[]
When Izanami got bored one day, she was offered by King Frost's a realm where she could toy with humans for the low low price of $5,000,000,000,000. After accepting the offer, it was filled with King Frost's signature Shadow Juice and transformed it into The TV World. Tohru Adachi was appointed by her as the ruler, but in reality it was an April Fools' joke. An added bonus is that the UnWorld this time would be connected to this place through televisions, and those with an Izanagi could traverse through the glass barrier. Yu Narukami with the help of Teddie sneezed too hard and she died, causing this place to collapse and become sacred again, but this wouldn't last as Igor would be sent to The Shadow Realm by Bob Saget. Wait...
Believe it or not Jack Frost once lived here before the place got torn down, but left due to being absolutely disgusted with Teddie, as he sensed Teddie would replace him as Atlus's mascot, but he was just paranoid.
Incarnation No. 5 - "Mementos"[]
Normal view of Mementos.
Mementos, is that one place of where everyone's mind goes when on vacation. But the thing to know is that it is a super big real estate as big as the UnWorld and is also everyone's mind world, or something like that. King Frost was actually scared of Fake Igor, and so did not stop him or anything. It collapsed when Fake Igor started charging people ¥9001 per second. Everyone got tired of paying high prices to live in a train station, so they decided to all leave the hotel at once. This caused the UnWorld and Mementos fused for like an hour, before Fake Igor's prisoner Mario burnt his bread, killing him and causing things to become normal again.
Also Mementos
Joker and Morgana would of helped, but the cat was too busy being a bishop to assist Mario and Joker was too busy dating all the girls all at once. Bob Saget realized his mistake from earlier of sending Igor to The Shadow Realm and put him back hoping nobody would notice. Greg Heffley died in this time from being forgotten also.