Board Thread:Lore Discussion/@comment-24372248-20150615183642/@comment-6881629-20150616135249

Thats the general theory of the Dreamsleeve if your not going to one of the realms of Aetherius or claimed by a Deadric Prince you end up there.

In Battlespire one of the Deadra of Nocturnal used it to hide from Mehrunes Dagon's invasion of the Shade Perilous.