The Elemental Realms are ten special planes of energy that exist within our universe. They each represent one of the Ten Elements.
They have existed far before anyone can remember, possibly having existed even before space and time began to crawl forward. These Realms are responsible for the presence of the ten Elements in our universe; Fire, Ice, Water, Electricity, Wind, Earth, Light, Darkness, Nature and Poison. All of them are natural concepts that have existed long before Mobius was even formed.
The Realms are not physical; it is impossible to step foot into these places of purest energy. However, there are still rumors that creatures beyond our comprehension exist in these Realms; quite fittingly, they are known as Elementals.
The Realms are not without their representatives, primarily in the form of ancient deities that have walked the planet for eons. Chief among these are The Elemental Gods; the children of Ka, the Great Wheel of Being. The Elemental Beasts were created by the Ka and Elemental Gods to help keep the Elemental Realms in balance with each other, and to keep their influence in check; one Realm should never become stronger than the others, after all.