When Tasha the Dark banished Koran using Tasha’s Guide to the Planes he found himself drawn into the page and transported into a place that exists outside of normal time and space.

The Place Between the Pages appears a cross between a Palace of the Imagination for those who visit it willingly, and a Prison for those trapped within it’s walls forever.

Within the domain time appears to pass slower allowing visitors to rest and recover, the walls are prismatic and ghostly in that you can see though them if you focus hard enough.

The entire palace respond to the users thoughts to provide whatever they need with walls, doors and hallways reshaping to lead one where their hearts desire.

Walking the hallways allows a visitor to peer into a series of rooms created to house and contain creatures from all over the Multiverse, some friendly. while others continue to rage against their imprisonment.

Seemingly ruling over this domain out of time is “Her”, a otherworldly variant of Tasha the Dark who acts as parent, jailer or host to those souls trapped within her realm.

Known residents within this realm include:
Madryck – The Ghost of a Old Man with a Fairy dragon Familiar.
Koraboros the Pit Fiend – A Hulking CR20 Pit Fiend who calls “her” Ma’ and appears to be ‘not all there’.
A Teenage Goth Vampire who’s bedroom appears to be a total mess.
Three Akanaloths trapped in what appears to be some kind of lab.
Three Hags who fit the classic ‘maid, mother, crone’
A Large Assortment of Black Cats, Quasit’s and various monsters.

Rooms:
A large Library
A hallway ending in a Mirror of Truth
A Ice Cream Parlor – complete with Mr Whippy Van
Extensive Gardens