Demi-Plane of Imprisonment

The Demi-Plane of Imprisonment is hidden somewhere in the depths of the Ethereal Plane, resembling a swollen, crystalline cyst nearly a mile in diameter. The ethereal substance surrounding the demi-plane boils with the dreamscapes of worshipers and others whose dreams the dark god within invades.
The demiplane’s origin is ancient, and the mythology of its founding appears in a hundred variations across a thousand prime material worlds, with the names changing to fit the local theology. But the stories all possess one common truth: the demiplane is the prison of a malevolent deity of oblivion called the Dark God, the Elder Elemental Eye, the Elder Elemental God, who seeks nothing less than the destruction of everything. Scholars believe the god within to be Tharizdun, sealed away at the beginning of the Dawn War.
So feared was this entity, that unable or unwilling to kill him, a pantheon of rival gods or other planar powers sealed him away. These legends are ancient, with fiendish historians placing the Dark God's imprisonment near the birth of the first deities spawned of mortal worship, and potentially before that point, suggesting the entity might not be a god in the same sense, but something else, maybe even originally native to another multiverse.

Type

Dimensional, Pocket