Prime Material Plane

The Prime Material Plane is the plane of existence that sits at the conjunction of all the other planes. Also known as the Material Plane, the Prime Material Plane is said to be at the centre of all other Planes of Existence, embodying them to varying degrees.
Runetalras is the name of the only known world within the Prime Material Plane, however, astrologers claim in addition to the moons and sun, there are other worlds within the night sky that may be home to an infinite number of other worlds with countless peoples. It does not appear the mages and clerics of Runetalras are able to teleport to these other worlds giving rise to the concept of Cosmic Sphere which dictate the ability to contact and interact with other worlds.
Overlapping the Prime Material Plane are the Echo Plane, the Shadowfell, Feywild, and Weave. Surrounding the Prime Material Plane and its Echo Planes, are the Inner Planes, those being the Elemental Plane of Air, Elemental Plane of Earth, Elemental Plane of Fire, Elemental Plane of Water, and the Elemental Chaos. Beyond the Inner Planes are the Outer Planes which are divided between the Upper Planes and the Lower Planes; the Lower Planes are the Abyss and Nine Hells, and the Upper Planes are the Celestial Heavens.