A shared universe or shared world is a set of creative works where more than one writer (or other artist) independently contributes a work that can stand alone but fits into the joint development of the storyline, characters, or world of the overall project. It is common in genres like science fiction.
It differs from collaborative writing where multiple artists are working together on the same work and from crossovers where the works and characters are independent except for a single meeting.
The term shared universe is also used within comics to reflect the overall milieu created by the comic book publisher in which characters, events, and premises from one product line appear in other product lines in a media franchise.
The term has also been used in a wider, non-literary sense to convey interdisciplinary or social commonality, often in the context of a "shared universe of discourse."
Fiction in some media, such as most television programs and many comic book titles, is understood to require the contribution of multiple authors and does not by itself create a shared universe and is considered a collaborative art form. Incidental appearances, such as that of d'Artagnan in Cyrano de Bergerac, are considered literary cameo appearances. More substantial interaction between characters from different sources is often marketed as a crossover. While crossovers occur in a shared universe, not all crossovers are intended to merge their settings' back-stories and are instead used for marketing, parody, or to explore "what-if" scenarios.
It can become difficult for writers contributing to a shared universe to maintain consistency and avoid contradicting details in earlier works, especially when a shared universe grows to be very large. The version deemed "official" by the author or company controlling the setting is known as canon. Not all shared universes have a controlling entity capable of or interested in determining canonicity, and not all fans agree with these determinations when they occur. A fanon may instead find some degree of consensus within the setting's fandom.
Some writers, in an effort to ensure that a canon can be established and to keep details of the setting believable, employ tools to correct contradictions and errors that result from multiple contributors working over a long period of time. One such tool is retconning, short for "retroactive continuity", which resolves errors in continuity that came about through previously-written conflicting material.
Readers may also object when a story or series is integrated into a shared universe, feeling it "requir[es] one hero's fans to buy other heroes' titles".
The expansion of existing material into a shared universe is not restricted to settings licensed from movies and television. For example, Larry Niven opened his Known Space setting to other writers initially because he considered his lack of military experience prevented him from adequately describing the wars between mankind and the Kzinti. The degree to which he has made the setting available for other writers became a topic of controversy, when Elf Sternberg created an erotic short story set in Known Space following an author's note from Niven indicating that "[i]f you want more Known Space stories, you'll have to write them yourself". Niven has since clarified that his setting is still to be used only "under restricted circumstances and with permission", which Niven granted to the several authors of the Man-Kzin Wars series. By contrast, author Eric Flint has edited and published collaborations with fan fiction writers directly, expanding his 1632 series.
A setting may also be expanded in a similar manner after the death of its creator, although this posthumous expansion does not meet some strict definitions of a shared universe. One such example is August Derleth's development of the Cthulhu Mythos from the writings of H. P. Lovecraft, an approach whose result is considered by some to be "completely dissimilar" to Lovecraft's own works. Less controversial posthumous expansions include Ruth Plumly Thompson's and later authors' sequels to L. Frank Baum's Oz stories and the further development of Isaac Asimov's Foundation universe by Greg Bear, Gregory Benford, and David Brin.
Many other published works of this nature take the form of a series of short-story anthologies with occasional standalone novels. Examples include Robert Lynn Asprin's Thieves' World, C. J. Cherryh's Merovingen Nights and Janet Morris' Heroes in Hell.
Busytown, created by Richard Scarry
CoDominium, created by Jerry Pournelle
Cosmere, created by Brandon Sanderson
Cthulhu Mythos, created by H. P. Lovecraft
Deathstalker by Simon R. Green
Dune by Frank Herbert
Seussville, created by Dr. Seuss
The Eight Worlds, created by John Varley
Emberverse, created by S. M. Stirling
Friardale Universe, created by Frank Richards
Golden Books universe (with exceptions with licensed characters)
Goosebumps, created by R. L. Stine
Heroes in Hell, edited by Janet Morris
Honorverse, created by David Weber
Known Space, created by Larry Niven
Liaden universe, created by Sharon Lee and Steve Miller
The Malazan Universe by Steven Erikson and Ian C. Esslemont
Middle-earth, created by J. R. R. Tolkien
Noon Universe, created by Arkady and Boris Strugatsky
The Shadowhunter Chronicles, originally created and edited by Cassandra Clare
Thieves' World, originally created and edited by Robert Lynn Asprin and Lynn Abbey
The Trillium series, created by Marion Zimmer Bradley, Andre Norton and Julian May
Uplift Universe, created by David Brin
The Way, created by Greg Bear
Wessex, created by Thomas Hardy
Wild Cards, created by George R.R. Martin
The Wizarding World, created by J.K. Rowling
Yoknapatawpha County, created by William Faulkner
Norman Bridwell's universe (such as Clifford the Big Red Dog, The Witch Next Door, and Tiny Family)
Eric Carle's universe
Agatha Christie's universe
S. E. Hinton's universe
Robert Ludlum's Bourne series
Rick Riordan's works based on mythology
Stephen King's universe
Robert A. Heinlein's Future History, or World as Myth novels
Universal Monsters – Dracula, Frankenstein and The Wolf Man (1931–1951)
Universal Monsters (2017–present)
Toho's Showa universe with Godzilla, Rodan, Mothra (1954–1975)
Toho's Heisei universe (1984–1995)
MonsterVerse (2014–present)
Alien vs. Predator – Alien and Predator (1979–present)
Freddy vs. Jason – Friday the 13th and A Nightmare on Elm Street (1980–2003)
View Askewniverse (1994–present)
Lake Placid vs. Anaconda – Anaconda and Lake Placid (1997–2015)
Marvel Cinematic Universe (2008–present)
DC Extended Universe (2013–present)
1950s
Series created by Mark VII Limited (1951–1979)
Guiding Light and other series (1952–present)
The Muppets and Sesame Street (1955–present)
77 Sunset Strip, Bourbon Street Beat, Hawaiian Eye and Surfside 6 (1958–1964)
1960s
Coronation Street and other series (1960–present)
Supermarionation (1960–1969)
The Beverly Hillbillies, Petticoat Junction and Green Acres (1962–1971)
General Hospital and other series (1962–present)
Whoniverse (1963–present)
Ultra Series (1966–present)
Batman and The Green Hornet (1966–1968)
Dragnet, Adam-12, Emergency! and Sierra (1967–1974)
Dad's Army and other stories (1968–1992)
1970s
The Mary Tyler Moore Show, Rhoda, Phyllis and Lou Grant (1970–1982)
Toei tokusatsu universe (1971–present)
Cannon and Barnaby Jones (1971–1980)
Diff'rent Strokes, The Facts of Life and Hello, Larry (1978–1988)
1980s
The Tommy Westphall universe (St Elsewhere, Homicide: Life on the Street, Law & Order etc.)
Magnum, P.I., Simon & Simon, Whiz Kids, Murder, She Wrote and The Law & Harry McGraw (1980–1996)
The Golden Girls, Empty Nest, Nurses and The Golden Palace (1985–1995)
The Cosby Show and A Different World (1984–1993)
Cheers, Wings, Frasier and The Tortellis (1982–2004)
Full House and other series (1987–present)
1990s
Law & Order franchise (1990–present)
The X-Files, Millennium and The Lone Gunmen (1993–present)
NYPD Blue and other series (1993–2008)
Walker, Texas Ranger and Sons of Thunder and Martial Law (1993–2001)
ER, Third Watch and Medical Investigation (1994–2009)
Hercules: The Legendary Journeys, Xena: Princess Warrior and Young Hercules (1995–2001)
JAG and other series (1995–present)
Everybody Loves Raymond, The King of Queens and The Nanny (1996–2007)
The Pretender and Profiler (1996–2000)
Buffyverse (1997–present)
Dawson's Creek and Young Americans (1998–2003)
2000s
CSI, Without a Trace and Cold Case (2000–present)
Crossing Jordan and Las Vegas (2000–2008)
Disney Channel sitcoms
One Tree Hill and Life Unexpected (2003–2012)
Nickelodeon sitcoms (2004–present)
Prison Break and Breakout Kings (2005–present)
Bones, The Finder, Sleepy Hollow and Rosewood (2005–present)
My Name is Earl, and Raising Hope (2005–2014)
Eureka, Warehouse 13 and Alphas (2006–2014)
Flashpoint and The Listener (2008–2014)
The Vampire Diaries and The Originals (2009–present)
2010s
Pretty Little Liars and Ravenswood (2010–present)
American Horror Story (2011–present)
Lab Rats, Mighty Med and Lab Rats: Elite Force (2012–present)
Arrowverse (2012–present)
American Crime Story (2016–present)
The spin-off media extending of the universe originating in Doctor Who has relatively little consistency given its division into audio plays produced by Big Finish and the BBC, the New Adventures universe novel, or a universe based on comics published in Doctor Who Magazine and other publications.
Within comics, the term shared universe has been used to reflect the overall milieu created by the comic book publisher in which characters, events, and premises from one product line appear in other product lines in a media franchise.
By 1961, Marvel Comics writer and editor Stan Lee, working with artists Jack Kirby and Steve Ditko, merged the bulk of the publisher's comics characters into the Marvel Universe. Marvel sets its stories in an increasing number of alternate realities, each with an assigned number in a greater "multiverse". DC and Marvel have also periodically co-published series in which their respective characters meet and interact. These intercompany crossovers have typically been written as self-limiting events that avoid implying that the DC Universe and Marvel Universe co-exist. Exceptions include the twenty-four comics released under the metafictional imprint Amalgam Comics in 1996, depicting a shared universe populated by hybridizations of the two companies' characters. Marvel has since referred to this as part of its setting's greater multiverse by labeling it Earth-692.
Although DC and Marvel's shared universe approaches to comics have set them apart from competitors in the industry, other companies have attempted similar models. Valiant Comics and Crossgen both produced titles primarily set from their inception in a single, publisher-wide shared universe, known respectively as Unity and the Sigilverse.
Action Lab Comics
Actionverse
Amalgam Comics
Amalgam Universe
CrossGen
Sigilverse
DC Comics
DC Universe
Image Comics
Image Universe
IPC Magazines / Rebellion Developments
2000 AD, Judge Dredd, Rogue Trooper, Strontium Dog and ABC Warriors
Malibu Comics
Ultraverse
Marvel Comics
Marvel Universe / Earth-616
Marvel Mangaverse (2005–2006)
Top Cow Productions
Top Cow Universe
Valiant Comics
Valiant Universe
Vertigo
Vertigo Universe
WildStorm
WildStorm Universe
Other
Harvey Comics
Peanuts
Peanuts animated universe (1964–present)
Jim Davis universe
Gnorm Gnat
Garfield
U.S. Acres or Orson's Farm
Tribune Media universe
All Time Comics by Fantagraphics Books
Originating in video games and the Internet
The influence of the Internet on collaborative and interactive fiction has also resulted in a large number of amateur shared universe settings. Amateur authors have created shared universes by contributing to mailing lists, story archives and Usenet. One of the earliest of these settings, SFStory, saw its spin-off setting Superguy cited as illustrative of the potential of the Internet. Another example is the furry-themed Tales from the Blind Pig created at the Transformation Story Archive which some limited publication. Other early examples include the Dargon Project, Devilbunnies, and the popular SCP Foundation wiki.
Mario franchise
Super Mario
Paper Mario
Doctor Mario
Donkey Kong franchise
Donkey Kong Country
Wario franchise
WarioWare
Yoshi
Sonic the Hedgehog franchise, ‘‘Bayonetta‘‘ and Nights
Puyo Puyo franchise
Hatsune Miku: Project DIVA franchise
Yakuza franchise
Sega Superstars/All-Stars franchise
Atlus
Persona and Shin Megami Tensei.
Kingdom Hearts (Final Fantasy and Disney)
Rockstar Games
Grand Theft Auto, Manhunt, Red Dead, and Bully.
Assassin's Creed, Watch Dogs and Far Cry.
Half-Life and Portal
Hero Universe
Total Annihilation series
Mickey Mouse and Donald Duck universes
Pinocchio, Fun and Fancy Free and The Adventures of Ichabod and Mr. Toad
Tangled and Frozen (2010–present)
The Pixar Universe (1995–present)
Gargoyles and W.I.T.C.H. (1994–2006)
Phineas and Ferb and Milo Murphy's Law (2007–present)
Sofia the First and Elena of Avalor (2012–present)
Earth-12041 – Ultimate Spider-Man, Avengers Assemble, Hulk and the Agents of S.M.A.S.H., and Guardians of the Galaxy (2012–present)
MTV
Beavis and Butthead and Daria
Nicktoons
The Adventures of Jimmy Neutron: Boy Genius/Planet Sheen
Avatar: The Last Airbender and spin-off/sequel The Legend of Korra
Nickelodeon-owned Klasky-Csupo universe (Rugrats/All Grown Up!, Aaahh!!! Real Monsters, The Wild Thornberrys, Rocket Power, and As Told by Ginger) (also part of Klasky-Csupo universe)
Nick Jr.
Dora universe (Dora the Explorer, Go, Diego, Go! and Dora and Friends)
WB animation
Looney Tunes, Merrie Melodies, Tiny Toon Adventures, and Animaniacs
The Lego Movie universe
DC animated universe
DC Animated Movie Universe
post-1974 Rankin-Bass Productions universe
Hanna-Barbera
The Flintstones and The Jetsons
Hanna-Barbera cinematic universe
pre-1986 MGM classic cartoon universe such as Tom and Jerry, Droopy, Barney Bear, Tex Avery cartoons, etc. (except the Pink Panther cartoon universe, which is still owned by MGM)
Cartoon Network
Cow and Chicken and I Am Weasel
Grim & Evil franchise and Codename: Kids Next Door
Ben 10, Generator Rex and The Secret Saturdays
Uncle Grandpa and Secret Mountain Fort Awesome
Adult Swim
Space Ghost: Coast to Coast, The Brak Show, Aqua Teen Hunger Force and Soul Quest Overdrive
China, IL and Brad Neely's Harg Nallin' Sclopio Peepio
Fox animated sitcoms
The Simpsons, and Futurama
Family Guy, American Dad!, and The Cleveland Show
FX animated universe
Animation Domination High-Def universe
DreamWorks Animation
Jay Ward universe (Rocky and Bullwinkle, Dudley Do-Right, George of the Jungle, and Fractured Fairy Tales)
Toei Animation Universe
Dragon Ball franchise, Jaco the Galactic Patrolman, and Dr. Slump
Digimon animated universe
Izumi Todo universe
Ojamajo Doremi series
Pretty Cure universe
Yu-Gi-Oh! Duel Monsters, Yu-Gi-Oh! GX and Yu-Gi-Oh! 5D's
TMS universe
Vocaloid mascot universe (e.g. Hatsune Miku)
Studio Ghibli universe
Gonzo universe
Production I.G. universe
Madhouse universe
Studio Gallop universe
Spümcø universe
Happy Days animated universe (1980–1982)
Klasky-Csupo universe (with the exceptions The Wacky Adventures of Ronald McDonald and Duckman)
Aardman Animations/Wallace and Gromit universe (e.i., Wallace and Gromit, Shaun the Sheep, and Timmy Time)
Disney on Broadway universe
Seussical universe
Hasbro
Hasbro Universe
Marvel Comics (1979–2004)
Rom: Spaceknight, The Micronauts and The Transformers (set in the Marvel Universe)
Marvel Productions and Sunbow Productions (1983–1987)
G.I. Joe: A Real American Hero, The Transformers, Jem and Inhumanoids
IDW Publishing (2005-present)
Transformers, G.I. Joe, Micronauts, Rom, Action Man and M.A.S.K.
Paramount Pictures (2009-present)
G.I. Joe, M.A.S.K., Micronauts, Rom and Visionaries
Star Trek (1966-present)
Star Wars (1977-present)
Stargate (1994–2011)
The Librarian (2004–present)
Marvel Cinematic Universe (2008–present)
Disney Channel crossovers
Henson/Muppets universe (except with licensed characters)
James Lowder. Shared Worlds // The Greenwood Encyclopedia of Science Fiction and Fantasy: Themes, Works, and Wonders / Edited by Gary Westfahl. Advisory Board Richard Bleiler, John Clute, Fiona Kelleghan, David Langford, Andy Sawyer, and Darrell Schweitzer. — Westport, Connecticut: Greenwood Press, 2005. — 1395 pp. ISBN 0-313-32950-8, ISBN 978-0-313-32950-0
