Editing Planescape (section)

==Description==
''Planescape'' encompasses numerous [[Plane (Dungeons & Dragons)|planes of existence]], creating an entire cosmology called the Great Wheel, which was originally developed in the 1987 ''[[Manual of the Planes]]'' by [[Jeff Grubb]]. This includes many of the other ''Dungeons & Dragons'' worlds, linking them via inter-dimensional magical portals.

===Cosmology===
[[File:Pgp 005 01.jpg|thumb|right|An artistic representation of the grand design of the Planes.]]
The ''Dungeons & Dragons'' cosmology as reflected in ''Planescape'' consists of a number of planes, which can be divided into the following regions:<ref name="Pyr"/>
* The [[Inner Plane]]s (representing planes of elemental nature, such as Water, Earth, Fire, and Air, as well as the Positive and Negative energy planes)
* The [[Plane (Dungeons & Dragons)#Ethereal Plane|Ethereal Plane]]
* The [[Prime Material Plane]]
* The [[Plane (Dungeons & Dragons)#Astral Plane|Astral Plane]]
* The [[Outer Plane]]s (representing alignments and the primary domains of the various deities, where their petitioners spend their afterlives)

''Planescape'' "solidified the Great Wheel cosmology that began in 1e and would later be reinstated in 5e as the dominant of three theoretical models".<ref name=":02" />{{rp|98}}

====Outer Planes====
The Outer Planes consist of: the Abyss, Acheron, Arborea, Arcadia, Baator, Beastlands, Bytopia, Carceri, Elysium, Gehenna, Gray Waste of Hades, Limbo, Mechanus, Mount Celestia, the Outlands, Pandemonium, and Ysgard.

===Sigil===
{{Main|Sigil (city)}}
''Sigil'', the "City of Doors", is located atop the ''Spire'' in the [[Outlands]]. It has the shape of a [[torus]], and the city itself is located on the inner surface of the ring. There is no sky, simply an all-pervasive light that waxes and wanes to create day and night. Sigil cannot be entered or exited save via portals. Although this makes it quite safe from any would-be invader, it also makes it a prison of sorts for those not possessing a portal key. Thus, many call Sigil "The Bird Cage" or "The Cage". Though Sigil is commonly held to be located "at the center of the planes" (where it is positioned atop the infinitely tall Spire), some argue that this is impossible since the planes are [[infinity|infinite]] in all dimensions, and therefore there can never truly be a center to any or all of them. Curiously, from the Outlands, one can see Sigil atop the supposedly infinite Spire.

===Factions===
{{Main|Faction (Planescape)}}
Within Sigil there are philosophy-derived factions. Before the event known as the ''Faction War'', the groups controlled the political climate of Sigil. Each of these factions is based on one particular belief system; one faction's beliefs make them enemies while others make them allies. There are fifteen factions in total.

====''The Faction War''====
{{Main|Faction War}}
In 1998, TSR published ''Faction War'', an adventure that effectively closed the book on Planescape, as it was then ending the product line. The culmination of several adventures leading up to that point, the Faction War brought an end to the factions' control of the city. Instigated by the power-hungry Duke Rowan Darkwood, factol of the Fated, in a bid to dethrone the Lady and rule Sigil himself, the war spread throughout the city before the Lady of Pain, with the aid of a group of adventurers (the players' characters), intervened.

===Sects===
Sects are in many ways identical to the Factions, differing in that they are not based in Sigil. Sects are often highly specific to the particular planes they originate from, though historically many of the Factions were once Sects and some Sects were once Factions.

===Rules===
There are three principles (or [[heuristics]]) governing the world of Planescape: the Rule-of-Three, the Unity of Rings, and the Center of the Multiverse.<ref>{{cite web | url = http://www.gamebanshee.com/planescapetorment/glossary.php | title= ''Planescape: Torment'' glossary}}</ref>

====Rule-of-Three====
The first principle, the Rule-of-Three, says simply that things tend to happen in threes.<ref>{{Cite web | url=http://official.planescape-torment.org/glossary.html | title = Planescape:Torment – The Glossary | access-date = October 2, 2007}}</ref> The principles which govern the planes are themselves subject to this rule.

====Unity of Rings====
The second principle is the Unity of Rings, and notes that many things on the planes are circular, coming back around to where they started.

====Center of All====
The third principle (fitting neatly into the Rule-of-Three above) is the Center of All, and states that there is a center of everything—or, rather, wherever a person happens to be ''is'' the center of the multiverse... From their own perspective, at least. As most planes are functionally infinite, disproving anyone's centricity would be impossible. In ''Planescape'', this is meant philosophically just as much as it is meant in terms of multiversal geography.<ref>Planescape Campaign Setting pg.3</ref>

The fact that anywhere could be the center of the multiverse in this view also implies that nowhere can be said to be the only absolute true center. This sparks a lot of arguments and violence since some people believe the City of Doors to be the center due to its uncommon number of portals to other planes and position in the Outlands and some factions also claim different centers, each with their own significance.