Walking the Planes

Records about the Elementals Realms are sparse. Given the fact that the more centuries past the less likely portals are to remain open, we are lucky to have the work of Valeande.

— High Sage Syronikir

Walking the Planes is an ancient but famous book written by the explorer Valeande. It tell the story of how an ordinary expedition to the Doromir Mountains turned into a whole other adventure. Within those mountains Valeande managed to find a portal to the Elemental Realms and would later write the story of his travels down.

History

Expeditions

Valeanda was already a well known High Elf explorer even before he travelled to the edges of Nervonia, commonly known as the Elemental Realms. It is not known how he got to the realms through a portal but not how he found it and opened it.
Once he returned with amazing tales of his travels it did not take long for other to try to do the same. They managed to go through the portal as well but most did not return or returned rather quickly. This period lasted for about a 100 years until suddenly the portal closed without ever opening again.

Influence

The book he created from his travels to the Elemental Realms is actually the main resource for any knowledge on those realms. Travel to the realms after Valeande seldom occured or was not possible to verify. It is for this region that the current cosmological model for the outer areas of Nervonia is based on his work.
However, because his work is rather vague on the actual form of the Elemental Realms there are several theories.

Yamaderis misplaced this image by Kefkjaco with heroforge

Elemental Realms

Elemental Paths by Kefkejaco with Inkarnate

Path or world

In his work Valeande describes the realms as both long paths and as larger worlds. This has given rise to two main theories for the form of the Elemental Realms. One states that the Elemental Realms there are a series of free floating paths each with their own gravity. From each path it is possible to see other paths free floating in Nervonia. Each path has its own element linked to it and travelling to other paths is mostly done at crossings.
The other theory states that the Elemental Realms are divided in zones where certain elements are dominant. According to this theory there are many large worlds in outer Nervonia and travel between them has to be done through portals.

Creatures

The edges of Nervonia, the Elemental Realms, have varying degrees of habitabilty. Some still have climates comparable to Niorath while others are influenced more heavily by the element from which they originated. And although all elements can at least be found in one occasion to some degree, it is not easy for every creature to live there.
The creatures living there are primarly those born from the elements themselves, the Elementals. Nonetheless from the travels of Valeande we know that there are other creatures there and even some civilizations. Valeande himself goes in great detail about his adventures in the flying palaces of avian humanoids. All of this is impossible to verify as nobody has visited those places again afterwards.

At least two civilizations are, however, believed to have made themselves home here. The Selefer are thought to have escaped to the fire realms whereas the Deep Gnome civilizations are believed to still inhabit the earth realms.

Fire Realm by Kefkejaco with Artbreeder