Movies and TV shows are coming around to an idea gamers are long familiar with: with a multiverse, anything is possible.
There are many other conceptualizations of the multiverse in fiction of course, but Moorcock's Eternal Champion codified the idea of variants worlds with some commonalities:
And of course, the Marvel Cinematic Universe has made the multiverse a key part of how it explains time travel, featuring prominently in the Avenger movies, and later Spider-Man and Dr. Strange.
Thanks in part to Elric's influence on Dungeons & Dragons, the various planes of existence and the campaign worlds therein have come to be described as a multiverse.
The two settings were Planescape and Spelljammer respectively. Planescape explored the basics of dimensional planes and how they might interact, positioning them as worlds in their own right (and not just exotic places to be visited by characters from the Prime Plane). Conversely, Spelljammer created crystal spheres, each of which represented a published or homebrew campaign world that characters could sail to and from. With the release of both of these settings the multiverse felt a lot less distant.
The baseline assumption for Fifth Edition is that the multiverse encompasses everything in D&D, including each DM's campaign. Mordenkainen's Monsters of the Multiverse further tweaked monsters by removing setting-specific lore and alignments, allowing near infinite variants of creatures that could fit in any world.
Given the massive diversity of gaming campaigns, it's not a surprise that D&D uses a multiversal model to explain the setting.
As franchises get long in the tooth, settings increasingly revert to the baseline of a multiverse to provide additional challenges. This has always been the case in D&D, where adventurers would visit other planes with more dangerous entities as they leveled up. "Normal" settings establish basics like gravity, a relatable ecosystem, breathable air, etc. By creating exotic places with alien worlds, the challenges increase and monsters that would surely destroy a home world can feasibly exist in their native dimension. The more powerful the heroes get, the more their adventures are likely to span other worlds -- and beings from other worlds are likely to visit their home world.
In short, once a setting has been around long enough, it defaults to a multiversal constant. No wonder then that D&D has come around to embrace the multiverse. The concept of a multiverse legitimizes every individual dungeon master's campaign. Like the multiverse itself, the possibilities are endless.
Multiversal
The concept of a multiverse has been around for some time, with rich roots in geek media. It debuted in the Flash comics in 1961 and was a key part of Michael Moorcock's novels in 1963.There are many other conceptualizations of the multiverse in fiction of course, but Moorcock's Eternal Champion codified the idea of variants worlds with some commonalities:
In the comic "Flasth of Two Worlds!" Earth-Two is introduced along with a DC multiverse, in which it's possible to have variant characters exist simultaneously. Barry Allen teams up with Jay Garrick (the Golden Age Flash) to defeat a rogue's gallery of villains. The idea of a multiverse kicked off a series of crossovers in which DC was encouraged to revive other Golden Age characters who were no longer in print. This concept has become a key part of the Flash franchise, featuring in the television series and the upcoming movie.Central to these works is the concept of an Eternal Champion who has potentially multiple identities across multiple dimensions. The multiverse contains a legion of different versions of Earth in various times, histories, and occasionally, sizes. One example is the world in which his Elric Saga takes place. The multiplicity of places in this collection of universes include London, Melniboné, Tanelorn, the Young Kingdoms, and the Realm of Dreams.
And of course, the Marvel Cinematic Universe has made the multiverse a key part of how it explains time travel, featuring prominently in the Avenger movies, and later Spider-Man and Dr. Strange.
Thanks in part to Elric's influence on Dungeons & Dragons, the various planes of existence and the campaign worlds therein have come to be described as a multiverse.
Multi-me, Multi-you
The idea of crossing universes is not new to D&D, and was part of the original Boxed Set. But the concept of a multiverse appears later in the First Edition of Advanced Dungeons & Dragons, in the Player's Handbook:The implications of such a multiverse went largely unexplored, with the implication that each individual dungeon master's campaign world existed in a network with a common rules system, and therefore a multiversal argument could be made that any character jumping from one game world to another would reasonably expect similar (but not the same) baseline worlds, even if the names were changed. It wasn't until two capstone settings were introduced that the multiverse was truly explored."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."
The two settings were Planescape and Spelljammer respectively. Planescape explored the basics of dimensional planes and how they might interact, positioning them as worlds in their own right (and not just exotic places to be visited by characters from the Prime Plane). Conversely, Spelljammer created crystal spheres, each of which represented a published or homebrew campaign world that characters could sail to and from. With the release of both of these settings the multiverse felt a lot less distant.
The baseline assumption for Fifth Edition is that the multiverse encompasses everything in D&D, including each DM's campaign. Mordenkainen's Monsters of the Multiverse further tweaked monsters by removing setting-specific lore and alignments, allowing near infinite variants of creatures that could fit in any world.
Given the massive diversity of gaming campaigns, it's not a surprise that D&D uses a multiversal model to explain the setting.
Multiversal Advantages
A universe of multiple worlds, all potentially variants that have some baseline assumptions but are otherwise unique, makes it easy to justify just about anything. In addition to creating a justification for time travel (like the Marvel movies), revive older characters (like the Flash comics), or provide a justification for familiar-but-similar world-hopping (like the Elric novels), a multiverse provides legitimacy to all worlds. A multiversal approach ensures that not just every world is possible, but that they all exist at the same time. This hodgepodge of ideas is well-known in video games like Fortnite and role-playing games like Rifts.As franchises get long in the tooth, settings increasingly revert to the baseline of a multiverse to provide additional challenges. This has always been the case in D&D, where adventurers would visit other planes with more dangerous entities as they leveled up. "Normal" settings establish basics like gravity, a relatable ecosystem, breathable air, etc. By creating exotic places with alien worlds, the challenges increase and monsters that would surely destroy a home world can feasibly exist in their native dimension. The more powerful the heroes get, the more their adventures are likely to span other worlds -- and beings from other worlds are likely to visit their home world.
In short, once a setting has been around long enough, it defaults to a multiversal constant. No wonder then that D&D has come around to embrace the multiverse. The concept of a multiverse legitimizes every individual dungeon master's campaign. Like the multiverse itself, the possibilities are endless.