Before there were humans or dwarves, before there were even worlds or the stars that light the night sky, there was but one thing in the universe-- the Mists. The mists touch all things. They are what binds the universe together, past present and future. They are the source of all good and evil, and all matter and knowledge. It is said that all forms of life, no matter how simple or complex, can trace their origins back to this one place.
Some immortal beings are apparently able to travel directly through the mist to step over from one world to the other, while mortal beings have to use special portals, such as the one located in the Tomb of the Primeval Kings.