See also Category:Planes
Planes are more esoteric, being levels of existence that differ from the standard Spatial-Temporal Reality and indeed are often perceived as non-substance based realms of spirit or dream-like existence, more in tune with essence than substance. Other planes are levels of existence that are more limited in scope, either by actual space, flow of time, or diversity in its reality. Further, their physical laws at times vary wildly from the broader reality which they are connected with.
Planes are difficult concepts to define. They do not qualify as alternate universes for a variety of reasons. First, they usually are far more limited in temporal and spatial terms than any known Universe. Second, they are not part of the Omniverse construct. Third, they are usually set apart as they either connect with or are contained within a Spatial-Temporal Reality, usually in one universe. Likewise, they do not qualify as other dimensions because they do not exist on a broader spectrum, nor are they accessible by means of inter-dimensional travel.
Unlike alternate universes, or other dimensions, planes are not usually accessed through more typical scientific means. Instead, planes are usually accessed through various mystical or supernatural means, including various forms of astral projection, mind or conscious altering states, or actual spell use. Similarly, it is also known that many planes serve as power sources for various forms of magic. Specifics vary across the spectrum, but many forms or schools of magic rely on the ability to use spells to draw energy of various forms from other planes of existence. This mystical nature thus becomes one of the key differentiating points to define planes from other levels of reality.
Little else has been revealed concerning them.
- Wikipedia Article on Planes