World of Dreams
Known among the Selar as Tan’del’lar, the World of Dreams is a world in its own right, though it exists as a reflection of Eurthasia. It tends to be of a elastic nature so that it is easily mutable by those who know how but it then will gradually or even rapidly come to reflect Eurthasia again. Making permanent changes to the World of Dreams, without making similar changes in Eurthasia is difficult or impossible.
The World of Dreams was created when the Gods of Light split the prime world (which until that point had many of the mutable characteristics of Tan’del’lar) during the Severing. The Outer Realms on which the Gods of Light supposedly reside are said to be accessible through the World of Dreams and that may explain why contact with such beings often comes via dreams.
Most pre-severed conscious beings such as the Selar can still witness and even cast themselves into the World of Dreams in a limited way. They do this often as part of resting (when others sleep). This however is a form of spiritual projection and is very different from entering the world physically.