The Planes (Aegir Supplement)
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The cosmology of Aegir is slightly different than typical D&D cosmologies. For the most part, the world consists of two planes: the material plane (Aegir) and the spiritual plane (Threysos). Within the spiritual plane, there are various sub-planes created by deities out of the stuff of Threysos. These planes are usually still technically part of Threysos, but are occasionally larger on the inside than the outside and often have vastly different characteristics than Threysos does.
This article will deal primarily with Threysos and the special characteristics of that plane. I will also discuss the major sub-planes, though small pockets of other planes are scattered all around Threysos, created and forgotten by gods and other immortals, and ripe for adventure. Finally, I will go through the major planes presented in the Dungeon Master's Guide and discuss how they fit into the Aegir cosmology.