From the game:
Somewhere just outside reality is a realm that mirrors our own. It isn't an exact reflection, but instead a realm distorted by the minds who retain a depth of imagination and wonder. It is a realm that has been sought by shamans since the dawn of history, it is a place sought through meditation, sutras and hallucinogenic drugs. Some know it as the astral plane; others call it the spirit realms or even the dreamtime.
This realm has always existed, beckoning the minds of the physical world, calling to them with wonder and hope. The realm of dreams is the source of imagination, the home of creativity and a place where anything is possible.
Dreams are a connection to this plane, a way for mortal minds to understand their reality in light of an infinite potential of wonder. Those who live in this realm are known by various names, some call them angels, gods or spirits, among themselves they are known as Phantasms.