Shared universe

A Shared universe is a literary technique in which several different authors share settings and characters which appear in their respective works of fiction, often referring to events taking place in the other writers' stories. It can also be called a "shared setting." It can be a metafictional device. Shared fictional universes tend to appear more frequently in fantasy and science fiction than in other genres.

Corporate examples

• The Star Trek and Buffy the Vampire Slayer franchises each have a vast empire of subsidiary and mostly non-canonical novels and comic books, and a vast community of dedicated, sometimes obsessive fanfiction writers.
• The Star Wars franchise is unusual in that, at least in theory, every official work in it is considered canonical and must fit with all the others, although George Lucas is not bound by the latter restriction.
• All Doctor Who licensed fiction is, at least in theory, set in the same shared universe as the television series on which it is based. However, since the BBC has a somewhat laissez-faire attitude towards the Doctor Who canon, divergent, sometimes contradictory, versions of the Doctor Who universe have appeared in different media (novels, comics, and audio dramas). These strands are sometimes referred to as separate universes (for example, "the Big Finish universe" or "the New Adventures universe"). Furthermore, due to both artistic and legal considerations, spin-offs from the spin-offs such as the Bernice Summerfield and Faction Paradox series, may or may not be considered to be part of the same universe as the officially licensed novels in which they originated.
• The Dungeons and Dragons role-playing game has millions of players worldwide, many of whom play characters in shared settings such as Faerûn, Eberron, and Ravenloft. There are also many novels and magazines dedicated to these shared settings. In addition, although these settings differ from one another in history and geography, they have many other elements in common (eg: elves live for several hundred years, but are not immortal; wizards must memorise spells each day); these settings are actually separate parts of a greater shared setting (Planescape).
• Marvel Comics, DC Comics, Archie Comics, and many other comic book publishers over the years have each had proprietary shared universes, in which characters from one comic book (such as Superman) often interact with characters from other comic books in the same universe (such as Wonder Woman). Series featuring a group or team of characters, each with their own individual adventures written by other writers, are common. From time to time, two comics publishers may jointly produce a story in which characters from their respective universes interact; these stories are commonly presented as "out of continuity" to avoid entangling the universes. At one point in the 1990's, DC and Marvel cooperated in the temporary, highly hyped, Amalgam universe, which blended elements from the two universes, including merged characters (e.g. Batman and Wolverine were combined as the Dark Claw).
• The cartoon libraries of Warner Brothers, Disney, Hanna-Barbera, and other animation houses each contain somewhat-independent stories featuring various combinations of their respective characters, created by a variety of writers and animators. Furthermore, Who Framed Roger Rabbit featured Toons from various cartoon universes, most notably a musical interlude with Donald and Daffy Ducks, and an action sequence with Bugs Bunny and Mickey Mouse. Doing so implied a metafictional "tooniverse" that produces animated movie stars, which later Toon-related works have expanded upon.