- "However, such as with our actual world, the expanses of the game multiverse will always have frontiers and unexplored territories. This fact, indeed, is what makes the AD&D game system so wonderful and appealing."
- — Gary Gygax, Unearthed Arcana, May 1985
The multiverse is the sum total of all possible worlds and realities in Dungeons & Dragons. It includes every official D&D campaign setting and every unofficial homebrew world. It may also be used in a more limited context to refer to the contents of a single campaign setting or planar cosmology.
The exact shape of the multiverse, the connections between worlds, and means of travel between those worlds are arbitrary, highly subjective, and vary based on the perspective of the inhabitants of different worlds.
The Dungeons & Dragons 5th edition Player's Handbook describes the multiverse of D&D worlds as follows:
- "The worlds of the Dungeons & Dragons game exist within a vast cosmos called the multiverse, connected in strange and mysterious ways to one another and to the other planes of existence, such as the Elemental Plane of Fire and the Infinite Depths of the Abyss. Within this multiverse are an endless variety of worlds.
The multiverse is described as a transfinite expanse of mind-boggling immensity. The shape of the vast cosmology of planes is practically impossible for an individual to objectively observe and may even appear differently from the perspective of different worlds.
A popular model of the multiverse is known as the Great Wheel, which describes the relationship of the plane with some accuracy. It includes the Material Plane where people live; the Inner Planes, which are the four basic elements of which other matter is ultimately made; the Outer Planes, arranged in an outer ring of infinite realms where the gods reside; and the transitive planes, which connect planes together. Outside of these lie other smaller spaces, such as demiplanes and extradimensional spaces.
However, the Great Wheel is not the only valid conception of the planes, and since most planar travel is conducted via spells or portals, the exact layout is effectively arbitrary and largely irrelevant. Other layouts include the World Tree, in which all worlds are connected by a great cosmic tree, and the World Axis, in which the Astral Sea floats above the Material Plane and the undifferentiated Elemental Chaos below.
The Material Plane is usually now considered a single realm containing every single Oerthlike material planet, which it is possible to physically travel between. An older interpretation still popular in many circles describes different worlds as parallel material planes, leading to terminology such as "Prime Material Plane" for one's own home world.
Most adventures take place within a certain world. A world is part of the multiverse with its own form of reality separate from the rest of the multiverse.
Various methods allow travel between worlds of the multiverse. It is possible to transfer from one plane to another, one world to another, and between multiple versions of reality.
A spelljamming ship allows travel between material worlds through a medium known as phlogiston.
It is difficult or impossible for any person to truly comprehend the nature of the universe. As a result, different organizations have wildly differing views of the multiverse.
The Doomguard believe that the multiverse is gradually falling apart, and embrace destruction rather than try to prevent it. The Mind's Eye believe that the multiverse provides knowledge available to the enlightened, while the Transcendent Order believe the multiverse is a massive single life form. The elemental Mephlings believe the multiverse is ultimately uncaring to life, while the Xaositects believe it is unpredictable.
The question of how the multiverse was created, and by whom, and why, is largely unknown. A myriad of cultures each have their own creation mythologies, often attributing the creation of reality to powerful or divine beings or a natural progression of nature.
Divine creation myth
Many cultures believe that a god or gods first created the multiverse.
The term "multiverse" and concept of the connectedness of every D&D world were largely popularized by Dungeons & Dragons 5th edition, although the name or concept appeared previously in some early editions.
AD&D 1st edition
Perhaps the earliest use of the term "multiverse" in a D&D sourcebook appeared in the original Players Handbook (1e) (1978), p.120:
- "There exist an infinite number of parallel universes of existence in the fantastic "multiverse" of Advanced Dungeons & Dragons. All of these "worlds" exist, but how "real" each is depends entirely on the development of each campaign referee."
AD&D 2nd edition
The nature of the multiverse and the connection between it and individuals are explored in the Planescape campaign setting sourcebooks.
D&D 3rd edition
The spell rope trick in the Player's Handbook (3.0) (2000) refers to "an extradimensional space that is outside the multiverse of extradimensional spaces". This is a change to the AD&D 2e version of the spell, which doesn't mention the term "multiverse".
Other sourcebooks use the term "multiverse" in reference to a DM's campaign setting. For example, Manual of the Planes (3e) (2001), p.41 says that "the Material Plane usually has particular characteristics because it's the heart of your multiverse." Mechanus is described as "the gear works for the multiverse", and Carceri its prison.
D&D 5th edition
All three core rulebooks of D&D 5th edition core rulebooks use the term "multiverse".
- "Does the #dnd tabletop RPG have one official setting? The answer is yes. That setting is the multiverse, which includes all #dnd worlds."
- "The worlds occupy pockets of the Material Plane—sort of like planets but in a space shaped by magic and divine forces."
The Far Realm is said to be outside the known multiverse.
- Player's Handbook (5e) (2014), p.5-6.
- The Complete Book of Necromancers (1995), p.94.
- Planar Handbook (2004), p.27.
- Planar Handbook (2004), p.43.
- Dungeon Master's Guide (5e) (2014), p.43-44.
- Dungeon Master Option: High-Level Campaigns (1995), p.44.
- Planar Handbook (2004), p.46-47.
- Planar Handbook (2004), p.11.
- Book of Artifacts (1993), p.103.
- DMGR4 Monster Mythology (1992), p.97,104.