Veil of Worlds

Description
The Veil of Worlds is an unlivable world that exists between the Human World and the Beneath. It is used primarily as a filter for beings crossing from either side.

Within the Veil
Inside the Veil is thought to be the Dream. Although impossible to prove, it's suggested that since souls must be dragged into it and do not appear in the Beneath, that they become trapped within the Veil. What is known, is that solid and semi-solid beings cannot exist within it. A mystical property of the Veil prevents beings from entering and automatically traverses them to the opposing world if an entry is attempted.

Beside the Veil
On either side of the Veil is the Beneath and the Human World. Because of its perfect placement, it acts as a filter, disallowing solid being from entering the Beneath (or the human world if they are already there). Non-solid beings are able to pass through the veil but unable to enter it.