Inner Plane

The Inner Planes are the fictional innermost planes of existence in the standard cosmology of the Dungeons & Dragons role-playing game. They are the building blocks of the multiverse, the elements and energies from which all of the material universe (the Prime Material Plane, or, in the 3rd Edition, simply Material Plane) is made.

The Inner Planes, the material building blocks of reality and the realms of energy and matter, stand in contrast to the intangible and esoteric Outer Planes, which include the realms of ideals, philosophies, and gods.

The Planes serve as a home for extraplanar creatures which magic-users can summon. High-level adventurers can quest on the Planes, which are usually dangerous without protective magic.

In the first edition there were initially four Inner Planes, consisting of the four classical elements of fire, earth, air and water, as well as the energy planes of positive and negative material, and the ethereal plane.

In Advanced Dungeons & Dragons 2nd edition, the Inner Planes intersect each other to produce a number of other Planes. Probably the best analogy describing their relationship to each other is that of an octahedron: the northern pole is the Positive Energy Plane, the southern pole the Negative Energy Plane, and at the middle four points lie the Elemental Planes (based on the four classical elements): Air opposite Earth, Fire opposite Water. They were an important part of the Planescape setting. Each edge is also either a para-elemental or quasi-elemental plane of its own.

Elemental Planes
The four Elemental Planes are the planes of Air, Fire, Water and Earth.

2nd edition also included the Para-Elemental and Quasi-Elemental Planes. The Para-Elemental Planes are 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 are 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 respectively. Around the Negative Energy Planes are Vacuum, Dust, Ash, and Salt.

Note that none of the opposing planes touch one another, 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. There is only one exception to this rule: the Prime Material Plane, which is composed equally of all 6 elements; Earth, Air, Fire, Water, Creation (Positive Energy), and Decay (Negative Energy).

Energy Planes
The Energy Planes are unique in that they are not composed of matter but rather a tangible form of creativeness or destructiveness. All life (or unlife) depends on them. Despite this, energy elementals or other forms of native life are not common. The Xag-Ya (positive) and Xeg-Yi (negative) energons were the earliest such denizens to be introduced.

Negative Energy Plane
Also called the Negative Material Plane (in 1st Edition), this plane is the home of stagnation, entropy, and the undead. Any unprotected living creature exposed to the Negative Energy plane has its life force rapidly drained and will die when they run out. Most Necromantic spells, including bolstering undead and "rebuke undead" abilities, draw on this plane and most undead creatures have an inherent connection to it.

Positive Energy Plane
Also called the Positive Material Plane (in 1st Edition), this is the plane of creation and energy, and is the total opposite of the Negative Energy plane. Despite the plane's life giving effects, unprotected living creatures entering the positive energy plane quickly become overloaded with life energy and may explode. Necromantic spells harming undead and "turn undead" abilities draw on this plane and most deathless creatures have an inherent connection to it.

Publishing history
In the original Monster Manual (1977) by Gary Gygax, the only elementals that appeared were those of fire, air, water, and earth. In the original Players Handbook (1978), no para- or quasielemental planes were mentioned. The Inner Planes were described simply as above (Earth, Fire, Water, Air, and what were then called the Positive and Negative Material Planes). The Ethereal Plane and Prime Material Plane were also counted among their number.

In Dragon #27 (July, 1979), Jeff Swycaffer suggested a far more expansive elemental scheme in which twelve new "elements" were proposed. The elements were envisioned here as a complex polyhedron with 18 square sides and 8 triangular ones; a small rhombicuboctahedron. Four of the square sides represented Fire, Air, Earth, and Water. Between these elements were four qualities: Cold (between Air and Water), Moist (between Water and Earth), Hot (between Earth and Fire), and Dry (between Fire and Air). These elements and qualities formed an "equator" around the polyhedron, equidistant between the "poles" of Good and Evil. Between the equator and Good were placed the qualities Pleasure, Fertility, Beginning, and Light. Between the equator and Evil were placed the qualities Pain, Barren, Ending, and Dark.

In Dragon #32 (December 1979), in his column "From the Sorcerer's Scroll," Gygax said that Jeff Swycaffer's ideas "were good indeed", but noted that vapor should be substituted for moist and dust instead of dry/dryness.

So it was that in Deities & Demigods (1980), the "Para-Elemental Planes" were listed as:
 * The Plane of Ice where Air and Water meet.
 * The Plane of Dust, at the conjunction of Air and Fire.
 * The Plane of Heat, where Fire and Earth converge (lava).
 * The Plane of Vapor, at the meeting of Earth and Water.

In 1983, The Land Beyond the Magic Mirror was the first place to feature a lightning quasielemental, although the description says they inhabit the Positive Energy Plane and the Elemental Plane of Air, indicating that Gygax didn't expect anyone to know what the Quasielemental Plane of Lightning was.

In Dragon #73 (May 1983), Gygax criticized the inner planar cosmology depicted in Deities & Demigods while taking sole responsibility for it.

Note that, in the torus, the Para-Elemental Planes (Ice, Dust, Vapor, Heat) occupy too much area. Discerning Students will also remark that three of these intervening planes are denoted by some material manifestation, while the remaining one is designated by a condition. Thus, the logical question: Which one in the series does not belong? Do not blame the Learned Authors of the work in which the depiction occurs—I am the one responsible for it, and I offer my apologies.

Getting back to the point of this article: Another reference illustration (Figure B, at right below), also from the DEITIES & DEMIGODS book, shows the Inner Planes (Material, Elemental, Positive, etc.). Isn’t it interesting to note how the Positive Material Plane sits upon the material multiverse as if it were a plate? Observe also how the Negative one serves as a saucer for the same body?

If these odd relationships have troubled you, Gentle Readers, half as much as they have disturbed me, you have been sorely put upon. I, for one, could stand it no longer.''

After several hours of rooting around in the mess which I laughingly term my files, I discovered my notes on the Inner Planes. Atop the heap was an illustration of a tetrahedral structure for the Elemental Planes proposed by my Worthy Confederate, Steve Marsh. (count ‘em) Para-Elemental Planes, viz. Lightning, Magma, Dust, Ice, Vapor, and Ooze—all material substances, not conditions, by the by! The four faces are the Positive Material, Negative Material, and Shadow Planes, plus the infinity of the Prime.

After fiddling with this structure for some time, Gygax decided (as described in the same article in Dragon #73) to change the structure from a tetrahedron to a cube in which four of the six faces were the "Inner Planes" described in the Players Handbook: Earth, Fire, Air, Water, and the Negative and Positive Material Planes. The edges of the cube, where the various faces met, represented "Para-Elemental" and "Quasi-Elemental" planes. Gygax listed the Para-Elemental planes, where the elementals mingled, as Smoke (where Fire met Air), Ice (between Air and Water), Ooze (between Water and Earth) and Magma (between Earth and Fire). He listed the Quasi-Elemental planes as Lightning (between Air and the Positive Material Plane), Steam (between Water and the Positive Material Plane), Radiance (between Fire and the Positive Material Plane), Mineral (between Earth and the Positive Material Plane), Vacuum (between Air and the Negative Material Plane), Ash (between Fire and the Negative Material Plane), Salt (between Water and the Negative Material Plane), and Dust (between Earth and the Negative Energy Plane).

This new structure became the default one for the 1st and 2nd edition AD&D game, described in greater detail in the Manual of the Planes (1987), the Planescape campaign setting (1994), and The Inner Planes (1998). In his review of the Planescape Campaign Setting boxed set, Gene Alloway mentioned that the set gives players a solid sense of "the sheer force of nature that drives all the Inner Planes. The Inner Planes don't have anything against you—they're hard on everyone." The cosmology remained the same in all these sources, though in Planescape the Negative and Positive Material Planes were renamed the Negative and Positive Energy Planes.

In the 3rd edition Manual of the Planes (2001), the paraelemental and quasielemental planes were removed, and the Inner Planes were assumed, by default, to be completely separate and not border one another. Paraelemental creatures were said to exist in both their constituent planes. Later 3rd edition sources, such as Sandstorm (2005), generally did assume the Inner Planes bordered one another. The quasielemental planes were never mentioned in 3rd edition at all, although an article on the Plane of Radiance appeared in Dragon #321 as the antithesis of the Plane of Shadow rather than as a quasielemental plane.

In the 4th edition of the game, the Inner Planes were replaced with a plane called the Elemental Chaos, which combined features of the Inner Planes, the Ethereal Plane, and Limbo, and also contained within it the Abyss. The Negative Energy Plane was combined with the Plane of Shadow and Ravenloft to form a plane called the Shadowfell.