Secrets of the Temblar
4e D&D has a cosomology that looks a bit like the map on the left. The Astral Sea drifts “above” the world, the Elemental Chaos drifts “below” the world, and the Shadowfell and Feywild are located “side by side” to the Mortal World.
There are a few differences from this cosmology in the Temblar campaign. The Shadowfell and Feywild overlap the Mortal World like shadows from Zelazny’s Amber books. All other planes do not have a geographical location but exist somewhere. The Astral Plane (not Astral Sea) does exist, as does the Elemental Chaos. The Abyss, however, is somewhere else entirely, as are the “good” planes from Planescape like Arborea, etc. You do not need to concern yourself with “where” these are in a spatial sense. Planes simply are. In addition, there may be many more planes included in the Ealthiros cosmology which have no corresponding plane in existing D&D settings.