The Inner Planes are the innermost planes of existence in the standard cosmology of the Dungeons and Dragons role-playing game. They are the building blocks of the multiverse, the elements and energies from which all else is created. See plane (cosmology) for the common meaning of plane as used in cosmology. ... The original Dungeons & Dragons set Dungeons & Dragons (abbreviated as D&D or DnD) is a fantasy role-playing game (RPG) published by Gary Gygax and David Arneson in January 1974. ... A role-playing game (RPG) is a type of game where players assume the roles of fictional characters via role-playing. ... The idea that the universe that we can observe is only part of the whole physical reality led to the definition of multiverse, the set of multiple possible universes. ... Generally, an element is a basic part that is the foundation of something. ...

Probably the best analogy describing their relationship to each other is that of a globe: the northern hemisphere is the Positive Energy Plane, the southern hemisphere the Negative Energy Plane, and at the equator lie the Elemental Planes (based on the four classical elements): Air opposite Earth, Fire opposite Water. A cream coloured globe This article is on a planet model. ... The equator is an imaginary line drawn around a planet, halfway between the poles. ... Several ancient Classical Element ideas exist. ...

In the older 2nd edition game, the Inner Planes were continuous streams that intersected with each other to produce a number of other Planes. The Para-Elemental Planes were produced where the Elemental Planes come into contact with each other: Smoke (Air and Fire), Ice (Air and Water), Ooze (Earth and Water), and Magma (Fire and Earth). The Quasi-Elemental Planes were produced where the Elemental Planes touch the Energy Planes: At the intersection of the Positive Energy Plane and the planes of Air, Earth, Fire, and Water are Lightning, Minerals, Radiance, and Steam, wheras around the Negative Energy Planes are Vacuum, Dust (http://mimir.net/dust/thebasics.shtml), Ash (http://mimir.net/ash/thebasics.shtml), and Salt (http://mimir.net/salt/thebasics.shtml).

Note that none of the opposing planes touched one another in the old cosmology as they cancel each other out violently, particularly in the case of Positive and Negative Energy. Thus, Fire and Water do not touch, nor do Air and Earth.

In the 3rd edition cosmology, however, the planes do not intersect and instead are represented as self contained spheres.

Energy Planes

Some sages theorize that the balance of power is shifting from the Positive Energy Plane to the Negative as the multiverse ages; others maintain that the shift is slowing and will one day reverse. Whatever the ultimate fate of the universe, the power of the Energy Planes is undeniable as all life (or unlife) depends on them. The heat death is a possible final state of the universe, in which it has reached maximum entropy. ... In cosmology, the Big Crunch is a hypothesis that states the universe will stop expanding and start to collapse upon itself; a counterpart to the Big Bang. ... Many religions have postulated an end to the Universe. ... Life is a multi-faceted concept. ...

Negative Energy Plane

Also called the Negative Material Plane or the Plane of Death, this plane is the home of entropy, stagnation and the undead. Most Necromantic spells draw on this plane. The thermodynamic entropy S, often simply called the entropy in the context of thermodynamics, is a measure of the amount of energy in a physical system that cannot be used to do work. ... Undead is a collective name for all types of corporeal and non-corporeal entities who were once alive in the normal sense, died, and then continued to exist in the world of the living, usually as a ghost or animated corpse. ... Necromancy is divination by raising the spirits of the dead. ...

Positive Energy Plane

Also called the Positive Material Plane or the Plane of Life, this is the plane of life and energy, and is the total opposite of the Negative Energy plane. Necromantic spells harming undead and turn undead abilities draw on this plane.