The Mists

"The Mists" refers to the medium in which the planes of the world reside. The Mists are composed of an unknown form of interdimensional medium. No experiments have been performed to determine the survivability of The Mists.

Various inhabitable planes exist floating within the mists. They are connected through the mists through great bridges. Any "motion" of these planes within the mists is unknown, and most likely incomprehensible with our math and science.

Speculation:

The Mists may be a more tangible form of the medium that seperates various realities. The planes suspended in it could be an example of unformed realities. The mechanics of it is far beyond our science.