Inner Plane

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.

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.

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

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).

Quasi-Elemental Planes

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 Radiance, Minerals, Lightning and Steam, wheras around the Negative Energy Planes are Vacuum, Dust, Ash and Salt.

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.

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.

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.

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.