Introduction to Planescape

Introduction to Planescape 2/4: D&D’s Unified Theory of the Planes

The planes are critical for helping players rationalize and organize information about some of the aspects of Dungeons & Dragons that are both the most fun and most confusing.  The 5e writers identify these problems, listing them as the justification behind the minimum number of planes required for most DND campaigns (DMG, p.43):

  • Where do Fiends and Celestials come from?
  • Where do the deities “reside”?
  • Where do mortal souls go after one dies [and how does resurrection function]?
  • How does one travel amongst the planes?

I would add the following other key questions that must be answered by the arrangement of the planes:

  • What is the relationship between deities and their followers, particularly their clerics?
  • Why does alignment matter, both of the planes and of individual PCs?
  • Why do deities/fiends/celestials intervene in the affairs of the Prime Material Plane?

Any good theory of the planes needs to be able to answer these questions.  Let’s dive in, starting from the Prime Material Plane and working our way out.

What is a Plane?

The designers of DND 5e demonstrate the importance of the planescape by making it the second chapter of the Dungeon Master’s Guide.  What they don’t do is define the term plane, and why it is important to organizing your game and providing a sensible account of its inner workings to your players.  

A plane is a level of existence characterized by continuity in certain traits that make it function as a cohesive whole and set it apart from other levels of existence.  Planes help players develop schema, or cognitive categories of organizing information, that they can use to understand and really immerse themselves in your DND world. For example, having a schema about the Plane of Limbo that everything is chaotic and changeable will help them immediately understand any specific world or setting that they are dropped into in Limbo.  By connecting this schema to each other, players can more easily conceptualize the entire DND multiverse, which in turn makes the game much more rewarding for many players, especially those keen on narrative continuity, immersive fantasy, and discovery (see the AngryGM’s discussion of Types of Player Fun).

It Starts with the Prime

The Prime Material plane contains all of the worlds that form the default settings for most DND campaigns. Prime Material worlds are inhabited by tangible beings made of flesh and blood or sometimes metal.  Magic works as described in the rulebooks. Gods deserve worship and their followers advance causes in their names, but gods themselves are abstract and not interacted with directly. When creatures die, their souls travel elsewhere and their bodies begin to decompose.  Elements and concepts, such as fire, water, magic, fear, are all present in different combinations, but the world is not a manifestation of any one concept or elements. The Prime may comprise a steampunk world, a high fantasy world, or even 21st-century earth.

Prime Material worlds reflect what we believe earth could be in an alternative universe.  The characters and the setting are different, but the core themes are the same. Roleplaying games also allow us to take themes from our own world but explore them from new or heightened points of view by adding magic, monsters or other dramatic elements.

To make the Prime Material a baseline that echoes the themes of our own world, four other types of plane are introduced to explain the origin of the Prime Material’s more fantastic elements.  They are the Transitive Planes, the Inner Planes (aka the Elemental Planes), the Outer Planes, and the Echoes of the Prime Material.

The Echoes of the Prime Material

The Shadowfell and Feywild are described as echoes of the prime material, parallel dimensions that recast the prime material in two very different mirror images.  The Feywild is a version of the prime material where everything is taken to the extreme. This is especially true of the passions of the heart and the chaotic primal forces of nature.  The Shadowfell, on the other hand, reflects the prime material as a shadow reflects its source, as a dark form stripped of warmth and detail.

Both planes were introduced in 4e, though the Shadowfell existed in prior versions as the Plane of Shadow.  Consequently, 2e Planescape materials do not reference either plane. The Feywild is useful for describing the origin of Fey magic and Fey creatures, such as familiars, while the Shadowfell is connected to certain spells and abilities as well.

Other planes, especially the Outer Planes, play a greater role in the unifying theory of the planes, so I have only touched briefly on these echoes, but for GMs interested in learning more about them or including them in their campaigns, I highly recommend Mike Mearls’s interview about them for DNDBeyond.

The Transitive Planes: The Highways of the Multiverse

The transitive planes resolve the problems of distance, time, and travel.  How does one travel through the planes? How do souls travel to their final destination?  How do separate planes--which by their nature are designed to be distinct from one another, connect?  Transitive planes! Or portals. Or magic. Or elemental vortices, or color pools, or the city of Sigil.  Really, all of these are variations on the road or the teleportation device (i.e., instant road). But what the transitive planes establish is a general system and theory, so that when players ask general questions about how the world works, the DM has answers that sound more convincing, and have built-into them a lot more plot hooks, than the tired response “because magic.”

Note that, according to the 5e Dungeon Master’s Guide, when one dies, one’s soul travels through the Astral Plane to the outer plane where one’s deity resides or that most closely matches her alignment (DMG p.24).  I find this description uncompelling and have developed my own system that I believe is more comprehensive and has smoother edges, which I will describe in a future article.

The Inner Planes: The Elemental Fuel for the Multiverse

The Inner Planes, aka the Elemental Planes, are manifestations of elemental forces such as fire, wind, and earth.  The Inner Planes may be reached via magic or portals, or via vortices, which connect to locations embodying the extreme nature of the corresponding element in the Prime Material Plane.  For example, the center of a tornado may be a vortex that leads to the Plane of Air, or the center of a volcano a Vortex leading to the Plane of Fire.

My personal theory is that the game purpose of the Inner Planes is to explain how worlds in the Prime Material Plane were constructed and why they have so much variety.  The energies of the plane were the physical building blocks that the deities used to shape the worlds of the Prime Material, and the elemental powers that fuel or are produced by these worlds provide the physical energy for the Prime Material.

Elemental creatures and elemental forces also have a rich history in D&D, and these planes help explain their existence.  When you summon an elemental, it comes from these planes, and when you cast a fireball, you tap into the magical weave and draw energy from the plane of fire.

The Outer Planes: Everything Depends on Belief

Now we’ve reached the heart of Planescape theory, the why.  Why do the gods exist, why do they intervene in mortal affairs, and why does alignment matter.

The Outer Planes are planes of thought, of morality, of philosophy, of belief.  Gods exist in the outer planes as manifestations of one or more these concepts. They reside in the plane or planar layer that most closely resembles their beliefs.  There are 16 outer planes arranged in a circle based on alignment. Eight more or less line up with one of the eight possible alignments, while eight others fall between two bordering alignments.  In the middle, embodying pure neutrality, is the Outlands, with the city of Sigil sitting atop an infinite spire in the center.

[Note: While the following is based on 2e lore, it is not, to my understanding, contradicted by 5e lore, and hence can be used to supplement existing 5e lore.]

The most critical feature of the Outer Planes for our theory of the planes is is that each god draws its strength from the belief of its followers on the Prime Material plane. 

In fact, without the sustained belief of prime followers, gods “die” and their bodies become physical masses aimlessly adrift in the Astral Sea.  This fact and its derivative conclusions explain the motivations of the most powerful forces in the multiverse, the gods.

Gods protect and expand their influence because their existence depends on it.  They gift some of their own power to their followers so that their followers directly increase the number of the god’s believers, or indirectly create conditions beneficial to worship of that god.  The more influential or powerful the follower (i.e., higher level clerics), the more power the god bestows upon her. Yet because they must draw upon their own strength, gods must be judicious in distributing their power, reserving it only for those who have proven themselves.  And, weakened by being forced to distribute much of their own power, the gods must work through proxies rather than directly intervening in Prime affairs.

It is not just the gods that draw their power from the Prime Material--it is also the Outer Planes themselves.  The balance of power of the Outer Planes is determined by the relative power of belief, and the Prime Material is the greatest source of belief in the planes.  If belief swings too much in one direction, the very makeup of the Outer Planes changes as part of one plane becomes absorbed by another (for example, the presence of great chaos may cause part of a lawful plane to transform into a nearby neutral plane, or have a lawful city simply disappear and reappear in a chaotic plane). 

The souls of the dead travel to the Outer Planes to be with their god, strengthening the plane that matches their alignment.  But even if such souls are destroyed, for example by a planeswalker venturing on the outer planes, the soul merges with its plane and continues to provide power to it.  Only in cases where souls are destroyed outside their home plane is their power lost completely. As a result, gods are hesitant to send their heavenly armies to wage battle in other planes or in the Prime Material, again preferring to advance their goals through proxies.  

As we can see, the core principle of Planescape theory is that the powers of the Outer Planes rely on the belief of ordinary people in the Prime Material.  This is why gods care about mortal affairs. It is why they intervene by lending their power to clerics and other proxies. It is why devils and demons seek to corrupt souls, but why, fearing death outside their home planes, typically rely on subterfuge and corruption rather than outright invasion.  

Planescape theory defines the stakes and the struggle not just of the PCs and their personal BBEG, but of the entire D&D multiverse.  Yet its brilliant stroke is to link these grand stakes to the individual stakes of the adventures undertaken by PCs on the Prime, and hence to give greater meaning to the PCs actions and their goals.

Next: Exploring the Setting

By adding Planescape into your game, you can add richness and depth to the world, provide greater meaning and context to what the PCs are trying to achieve, and answer many of the seeming contradictions between D&D’s rules and lore.  Many of the best resources for how to do this came from Second Edition’s Planescape Setting, so that seems like a good place to start. But in order to effectively draw from those resources, GMs need to understand the Planescape specific-setting for which they were created.

In Part III of this Introduction to Planescape Series, Understanding the Core Setting, I will introduce the key elements of the setting.  We will then have all the background we need for the final article of the series, which will discuss how -- and how not -- to add Planescape to your own campaign.