The Elemental Realms are the realms of the four elements: fire, water, air, and earth. They each represent their specific element and are the sources of said elements. Without these realms, the four elements would not exist.
Pyronia
Pyronia is the elemental realm of fire. It is a fiery mirror of the Material Realm. Everything here is composed of fire, including buildings. While it is too hot for anything from the Material Realm to survive here, there are creatures native to Pyronia, also composed of fire.
Aquanius
Aquanius is the elemental realm of water. It has the appearance of a vast ocean of endless depth and no surface no matter how far up one swims. Non-aquatic creatures from the Material Realm cannon survive here without some method of breathing underwater.
Gustormria
Gustormria is the elemental realm of air. The realm is pure chaos. There is no land here. Only an endless void of violent winds stronger than the most powerful hurricane.
Terranorga
Terranorga is the elemental realm of earth. It is a vast, endless landscape of rock and dirt. It is the least hostile of the Elemental Realms to denizens of the Material Realm. It is still not hospitable to them though. There is no food or water here that a non-earth being can consume.