The Elemental Realms
The Elemental Realms are the universal source of elemental material, created in the beginning with the First Work. There are six elemental realms: Air, Earth, Fire, Metal, Water, and Wood. The elemental planes each have relationships with one another and with the mortal realms, as well as with the Outer Realms, although to a lesser extent.
The Elemental Realms are home to genies, elementals, and other creatures closely tied to the power of the six elements. It's a common misconception that each of the elemental planes consist exclusively of their own element. This was once true, near the beginning of the First Work; but after the Second Work, bits of each element found their way into the other's realms, not unlike how specs of different paints make their way into each other on a painter's palette.
Each of the Elemental Realms are visible from the Mortal Realms, though the times at which they are visable and how they appear varies for each realm and from which side of the Mortal Realm one views them from. The regular precence of the Elemental Realms in the skies of the Mortal Realms has resulted in a great deal of associations with them, especially with regards to time and seasons.
