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->''"They were independent, separate stories. But now...the stories are combining, that's why the worlds are becoming one."''
-->-- '''[[Series/KamenRiderKiva Wataru Kurenai]]''', ''Series/KamenRiderDecade''

When an author or creator takes two previously unrelated works and puts them into a single, shared {{continuity}}.

[[SpeculativeFiction Sci-fi]] and fantasy authors don't always write all their novels in the same continuity. A budding new author's first published book might be about {{space pirate}}s in the 27th century, while his sophomore effort might instead be about 21st century scientists reverse-engineering a flying saucer. In response to popular demand, he might end up writing a {{sequel}} to one, or even both of these novels. Flash forward about 20 years -- the author has grown wealthy from writing stories about Captain Flash Orangebeard and Dr. Smith of Mars, but he's running out of ideas and the two [[LongRunners long-running series]] are in danger of getting stale. What does he do to keep the public's interest, and breathe new life into the storylines?

''Combine them!''

Many long-lived genre authors tend to resort to Canon Welding, usually at a later point in their career. They combine two or more distinct series they've created into a single continuity. This isn't just a one-off {{Crossover}}; for series with radically different premises, the foundations of one or both stories can be altered forever.

By combining the two series together, the author can introduce fans of one series to characters they may not be familiar with, inducing them to go out and buy the works in that series, and hopefully attract high sales from fans of both storylines. When done well, it can add a more epic feel to the tale, explore aspects of the two storylines not previously delved into, and make lots of money for the author and his publisher (and there are many examples of this, perhaps most famously ''Literature/TheLordOfTheRings''). When done poorly, especially with stories with radically different settings or styles, it looks and feels like a shallow money-grab and can potentially be a [[JumpTheShark shark-jumping]] moment for both series.

ModularFranchise is when it's done at a corporate level. Compare SharedUniverse, which can be created through Canon Welding if it wasn't shared from the beginning.


* Creator/ChrisBoucher's Franchise/DoctorWhoExpandedUniverse Literature/PastDoctorAdventures novel ''Corpse Marker'', and his semi-licenced audio series called ''Kaldor City'', both indicate that ''Series/BlakesSeven'' takes place in the Franchise/{{Whoniverse}}. Specifically, these show that ''Blake's 7'' takes place in the same time period as Boucher's popular ''Series/DoctorWho'' story "[[Recap/DoctorWhoS14E5TheRobotsOfDeath The Robots of Death]]".
** This was very nearly canonical, as it happens; the [[OutsideContextProblem invasion force from another galaxy]] from the finale of Season 2 of ''Blake's 7'' were intended to be the Daleks at one point, but for one reason or another the idea was dropped.
** Creator/DouglasAdams' character Professor Chronotis from the novel ''Literature/DirkGentlysHolisticDetectiveAgency'' came from Adams' ''Doctor Who'' TV serial "[[Recap/DoctorWhoS17E6Shada Shada]]", which was left incomplete due to an electricians' strike. In the novel, at least partially for copyright reasons, it's not explicitly stated that Chronotis is a Time Lord in hiding, but it's clearly meant to be the same person. There's even an oblique little reference at the end to [[TheNthDoctor a strange young man]] permanently disabling his time machine while the POV character wasn't around...
* In TheFifties, [[ComicBook/DisneyMouseAndDuckComics Disney Comics]] began to spread until the {{canon}} of the comic stories encompassed not only the regular Donald-Mickey-Silly Symphonies[[note]]The ''Silly Symphonies'' universe refers to Bucky Bug and the Three Little Pigs, mainly.[[/note]] melting-pot, but also several animated features by the studio, the most notably integrated into the canon being ''Film/SongOfTheSouth'', ''Disney/SnowWhiteAndTheSevenDwarves'' and ''Disney/{{Pinocchio}}''. It was later taken to ridiculous extents in TheSixties and TheSeventies, as the creators were beginning to run out of ideas. Aside perhaps of ''Snow White'', ''The Sword and the Stone'' and ''Song of the South'', the stories featuring such crossovers are very much CanonDiscontinuity, though some fans disagree with that decision of the company — they say that some of those stories were ''bad'', sure, but that they were bad because the writers didn't do their job, not because the crossover idea in itself was bad.
* ''VideoGame/SuperRobotWars'' is already a {{Crossover}} series, with nearly as many canons as it has games -- most entries take place in their own continuities, created by fusing together the stories of whichever HumongousMecha shows are featured in that particular installment, but there are a few characters who show up in multiple continuities, and while most of them are AlternateUniverse versions of each other, the likes of Gilliam Yeager for example, whose gimmick involves hopping between dimensions, is implied to be the same individual in all his appearances, no matter what continuity he's in. This in turn would make any games with Gilliam in them part of the same {{Multiverse}}.
* The ''VideoGame/EndlessFrontier'' series, which crosses over with both ''[[VideoGame/SuperRobotWarsOriginalGeneration Original Generation]]'' (which features Gilliam) and the even-more-mega-{{Crossover}} ''VideoGame/NamcoXCapcom''. And since ''VideoGame/NamcoXCapcom'' contains everything from ''Franchise/StreetFighter'' to ''VideoGame/{{Xenosaga}}'' (which also crosses over to ''Endless Frontier'') to ''VideoGame/{{Klonoa}}'', there are versions of all of those characters (but not the same versions that exist in their original games, yet still ''a'' version) in the Banpresto multiverse. With ''VideoGame/ProjectXZone'', any Creator/{{Capcom}} and Creator/BandaiNamcoEntertainment series not already included into this multiverse will most likely be added; however, there will also be dozens of Creator/{{Sega}} series in the game like ''VideoGame/VirtuaFighter'' and ''VideoGame/ValkyriaChronicles''.
* ''Franchise/KamenRider'':
** The franchise has had this going since the beginning. The Showa-era shows ([[Series/KamenRider original]] through ''Series/KamenRiderBlackRX'') explicitly took place in the same universe, and the previous Riders would often show up near the end of the latest series to help out [[TheHero the current hero]]. The movies produced in the hiatus years (''Film/ShinKamenRiderPrologue'', ''Film/KamenRiderZO'', ''Film/KamenRiderJ'') and the Heisei shows (''[[Series/KamenRiderKuuga Kuuga]]'' onwards) abandoned this, except for a few rare crossover events. ''Series/KamenRiderDecade'' deliberately says that the Heisei shows all occupy their own separate universe...and then has the first nine (''Kuuga'' to ''[[Series/KamenRiderKiva Kiva]]'') forcibly merged, with Decade forced to travel to alternate versions of said worlds in an attempt to fix everything...and then there's the ''Decade'' movie ''All Riders vs. Great Shocker'', which crosses over with the entire Showa-era universe as well. ''Movie War 2010'' also adds ''Series/KamenRiderDouble'' to the mix. Then ''Series/KamenRiderFourze'' decided to just bite the bullet and imply at the end of episode 2 that every show in the franchise is set in the same universe, with WordOfGod saying that they're going to {{Retcon}} the elements of ''Decade'' that didn't work. For extra humor, ''Series/KamenRiderKabuto'' has a brief in-character cameo by the actor who plays Rider-1 in TheRemake ''Film/KamenRiderTheFirst'', and ''Series/KamenRiderRyuki'' had a DVD-exclusive joke episode where the protagonist [[AllJustADream dreams]] that he teams up with Series/KamenRiderAgito to battle Agito's EvilTwin.
** ZO and J fight a multi-seasonal batch of monsters in Kamen Rider World (8-minute theme park thingy, may not be canonical but never said not to be, and not contradicting anything) which puts ''all three'' hiatus movies (yes, Shin provided a monster) into old-school KR continuity. Kuuga's mention of a Professor Hongo (and an imitation of him, which means he ''must'' have known ''the'' Hongo) put Kuuga and Agito into it as well. However, Decade makes the multiverse more complicated with its {{alternate universe}}s bearing variable resemblance to -- and ''rarely'' literally being -- the worlds of the actual series it's crossing over with. We even get Black and Black RX as separate worlds, as well as Kuuga and Agito, with alternate versions of some of the same people. Even more so, late in ''Double'' a member of [[NebulousEvilOrganisation Foundation X]] can be seen looking over data on OOO's Core Medals. Nothing came of this for over a year, until the crossover ''Film/KamenRiderXKamenRiderFourzeAndOOOMovieWarMegamax'' revealed that Foundation X would be playing a role, this time using the Astro Switches from ''Fourze''...and that Double and the first seven Showa Riders would be teaming up with Fourze and OOO. Given how Astro Switches pretty much ''are'' Gaia Memories this makes some sense (except for the Last One thing).
** Some ''Decade'' worlds have versions of Riders of other worlds with no dimension-hopping. For example, Dark Kabuto, Dark Kiva, Ryuga, and Orga live in a world where monsters rule, and have no connection to ''Kabuto, Kiva, Ryuki,'' or ''Faiz.'' It's the ''second'' Ryuga we meet, and no, the first wasn't in the World of Ryuki, either.) It also means Double and OOO take place in the World of the Rider War, as Double does no dimension hopping to meet Decade, and OOO does no dimension hopping to meet Double in any of their multiple teamup occasions.
** Decade's own MindScrew-itiude and AWizardDidIt attitude makes it nigh useless for working out continuity issues [[PowerCreepPowerSeep or finally answering which of your favorite Riders can kick the other's ass]]. Post-Decade teamup occasions not requiring any dimension-hopping (as it was with pre-Decade teamup occasions) would seem to have all things ''Kamen Rider'' in one universe, with past Riders still out there after they leave our sight (like any character in any show who has been PutOnABus.) It would seem that none of the AR Worlds were the one universe KR usually takes place in.
** As closest anyone can figure, here's how the Kamen Rider multiverse seems to work: The Showa era Riders and the 3 intermediate Riders (Shin, ZO, and J) take place in a singular continuity, as we saw. The Heisei era shows from Kuuga to Kiva (plus most of their movies) ''appeared'' to each take place in their own continuity, so completely separate were they, with the notable exception of Kiva and Den-O (the second Den-O movie has the Kiva gang cameo, and Kiva himself joins in the final battle) and the possible exception of Kuuga and Agito (there's a reference, and there are a few points that take some FanWank to make fit neatly.) Decade takes place all over the multiverse, but the opening episode and and the end of Movie Wars takes place in the same continuity as Double (whose appearance in Decade's movie can be chalked up to his universe meshing with Decade's). Speaking of Double, all of the series from Double onwards exist in the same continuity, which also contains variations of every Rider from Ichigo to Kiva, just not exactly as we saw them in the series. As far as OOO is concerned, his movies seem to be more canonical than his actual series is.
** However, the more we see of Riders old and new it makes more sense to just toss Decade out: its "AR Worlds" are clearly not the originals, so the World of Blade that's like a workplace sitcom with Riders and the World of Ryuki that's like a legal drama with Riders being separate worlds tells us ''nothing whatsoever'' about the canonicity of the series that they resemble InNameOnly. When it comes to the actual shows, the assumption made by fans that when SupermanStaysOutOfGotham it means Metropolis and Gotham are in completely separate and unrelated ''universes'' is something that ''never'' had canonical support, and now that Riders meet ''all the time'' it goes from plausible FanWank to something that really doesn't have a leg to stand on.
** However, don't put away your migraine medicine ''just yet: OOO, Den-O, All Riders: Let's Go, Kamen Rider'' would have the ''Decade'' World of Kuuga BigBad instead of the ''Series/KamenRiderKuuga'' Big Bad representing the Grongi in the LegionOfDoom, which would have welded Decade and its madness right back in...if it weren't for the fact that the movie's ending implicitly makes the whole ordeal non-canonical to everything by virtue of [[spoiler:settling on a CloseEnoughTimeline where, in regards to ''Kamen Rider OOO'', Hina doesn't know Eiji]]. (Also, ''every'' character who appeared in Decade had their updated design from that series instead of their original designs, but that can be ignored - ''you'd'' use the shiny Decade suits instead of making all new ones that ''don't look as good'' in order to perfectly match the 1970s versions.)
** More out-of-series welding: ''Let's Go, Kamen Rider'' also gives us cameos of Inazuman, Series/{{Kikaider}}, Kikaider 01, and even ''Series/KaiketsuZubat''. So basically everything with Creator/ShotaroIshinomori's name on it officially coexists now, even if you didn't take ''Goranger vs. JAKQ'' (which had ''Series/KamenRiderV3, Series/KamenRiderAmazon'', and ''Series/{{Kikaider}}'' stated to be fighting the same LegionOfDoom overseas.) seriously before. Then one of the ''Kamen Rider Fourze'' movies goes and introduces Inazuman... based on ''Inazuman'' the manga, not the show, and so not the Inazuman encountered in ''Let's Go Kamen Riders.''
*** And then ''Series/KamenRiderGaim'' meets up with Kikaider. Namely, the version from ''KikaiderReboot'' instead of the one we met in "Let's Go, Kamen Riders."
** ''Series/MaskedRider'', the not well received American adaptation of ''Black RX'', was launched with a PoorlyDisguisedPilot in a ''Series/MightyMorphinPowerRangers'' episode; much later, ''Series/PowerRangersInSpace'' crossed over with ''Series/NinjaTurtlesTheNextMutation'', which makes all three American series share a verse. All three are produced by Saban, which wasn't so bad back then, but as of 2009...
** Take all the crossovers above, put two plus two with the ''Kamen Rider'' and ''TMNT'' {{multiverse}}s separately established by ''Decade'' and ''WesternAnimation/TurtlesForever'' respectively[[note]]Incidentally, both are 2009 anniversary specials.[[/note]], and toss in both the canonical ''Series/SamuraiSentaiShinkenger'' arc of ''Decade'' and ''VideoGame/TeenageMutantNinjaTurtlesSmashUp'' for kicks. End result? ''Kamen Rider'', ''Power Rangers'', ''Franchise/SuperSentai'', ''TMNT'', the ''Franchise/UltraSeries'', and ''VideoGame/RavingRabbids'' are all part of the multiverse. It's gotten to the point that, near as anyone can tell of the yet-unreleased ''Film/KamenRiderXSuperSentaiSuperheroTaisen'' movie, nobody except Marvelous and Decade know what the hell is going on. Even the narrator is baffled. And with Compati Hero Series ''The Great Battle IV'' this would tie in ''Franchise/{{Gundam}}'', the ''Ultra Series'', and ''Kamen Rider'', et al. with the aforementioned ''VideoGame/SuperRobotWars'' and... well. Just let your imagination go wild, one supposes.
* Speaking of ''Franchise/{{Transformers}}'', it was split from its very beginning into separate comic and cartoon continuities. However, this rapidly splintered further and further, with different comics in different continuities being introduced, anime series being created, the introduction of the ''WesternAnimation/BeastWars'' and ''WesternAnimation/BeastMachines'' ranges which combine elements from previous continuities, [[Film/{{Transformers}} the live-action movies]] and so on.
** In the mid-2000s, writer Simon Furman ruled that every single ''Franchise/{{Transformers}}'' continuity forms part of a massive {{multiverse}} of different timelines, dimensions and universes, and sometimes featured crossovers in his stories (for example, the Generation One Galvatron and several others making a cameo appearance in a ''Anime/TransformersArmada'' comic). He also ruled that Unicron and Primus are constant forces in this multiverse, and though they can be destroyed in one reality their consciousness lives on in another. Curiously, his [[ComicBook/TheTransformersIDW next range of comics for IDW]] seemed to separate from this idea altogether.
** The canonical explanation of how multiversal singularities work, using [[Film/{{Transformers}} The Fallen]] as an example, [[MindScrew truly has to be read]] [[VoodooShark to be believed.]] [[http://tfwiki.net/wiki/Multiversal_singularity Here's a link.]]
** It gets better. Courtesy of Axiom Nexus, '''any''' Transformers series can interact with any other.
** Even better, the Transformers franchise itself was an amalgamation of several unrelated lines of Japanese die-cast toys (Jetfire/Skyfire was a [[Anime/{{Macross}} VF-1 Valkyrie]]), with most of the welding done by the fine folks at Marvel Comics and Sunbow Productions.
** The Transformers also went full circle when they crossed over with ''[[Comicbook/TheAvengers the New Avengers]].'' To say nothing of their participation in the ''Infestation'' crossovers at IDW, which suggests that, among others, ''Franchise/StarTrek'' and the ''Franchise/TeenageMutantNinjaTurtles'' are also part of the same multiverse.
** ''Regeneration One'', the continuation of the original Marvel series (disregarding the ''Generation 2'' series), concludes that the Grand Plan of Primus is to eventually create one "optimal" universe that comprises the best features of the various realities of the multiverse. And yes, Simon Furman wrote that series. (It also features a team-up of [[spoiler:Rodimus Prime and his cross-dimensional counterparts]].)
** The ''Transformers'' and ''Franchise/GIJoe'' often take place in the same universe. The G1 cartoon continuity also includes ''WesternAnimation/{{Jem}}'', ''WesternAnimation/{{Inhumanoids}}'', and ''WesternAnimation/{{COPS}}''; most of these series all had cameos from Hector Ramirez, an in-universe news reporter and a [[NoCelebritiesWereHarmed takeoff on Geraldo Rivera]]. ''WesternAnimation/MyLittlePonyAndFriends'' was close to being in the same universe, due to ''WesternAnimation/MyLittlePonyTheMovie1986'' nearly including scenes where Firefly encounters Shipwreck of ''G.I. Joe'' (who was drunk) and Optimus Prime.
** The [[Fanfic/TheElementsOfHarmonyAndTheSaviorOfWorlds Hasbroverse]] follows a similar premise, which also includes ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' and ''WesternAnimation/DungeonsAndDragons''. The author sets the G1 MLP as G4's distant past, and used some BroadStrokes by using mostly Marvel's ''[[ComicBook/GIJoeARealAmericanHeroMarvel G.I. Joe]]'' and having the G1 Transformers each possess a spark (a concept introduced in ''WesternAnimation/BeastWars''). The Earth Defense Command, meanwhile, is a descendant of both the original Joe Team and their Russian counterparts, the Oktober Guard; their respective leaders (General Clayton "Hawk" Abernathy and Colonel Ivan Brekhov) are now the leaders of the US and Russia, while Cobra [[CurbStompBattle got decimated in 1994]] after an ill-advised attack on the Decepticons; only Cobra Commander and a few others managed to escape.
** When a Matt Trakker figure was released as ''Specialist Trakker'' in one of the ''G.I. Joe'' toylines, ''WesternAnimation/{{MASK}}'' was ''adopted'' into the ''G.I. Joe'' universe. (''M.A.S.K.'' originally started as Creator/{{Kenner}}'s counterpart to the Joes and the Transformers; it came under Hasbro's umbrella when tkey acquired Kenner Parker Tonka in 1991).
** And ''[[ComicBook/Revolution2016 Revolution]]'' not only welds together their ''Transformers'' and ''[[ComicBook/GIJoeIDW G.I. Joe]]'' comics [[ComicBook/HasbroComicUniverse into one universe]] (with the statement being that all the ''Joe'' issues took place during a time where the Cybertronians were absent from Earth), but also brings in rebooted versions of [[ComicBook/RomIDW Rom the Space Knight]], [[ComicBook/MicronautsIDW the Micronauts]], ComicBook/ActionMan and WesternAnimation/{{MASK}}[[note]]the ''ComicBook/JemAndTheHolograms'' comics are an odd case - they apparently exist in the new Hasbro Universe, but for "reasons of tone" they're [[ExiledFromContinuity pretty much in their own little bubble]]; the ''[[ComicBook/MyLittlePonyFriendshipIsMagicIDW My Little Pony]]'', ''ComicBook/DungeonsAndDragons'', and ''TabletopGame/{{Clue}}'' titles aren't part of it at all[[/note]], with all sorts of connections between characters and plot threads between everything - Miles Mayhem was a member of Joe Colton's Adventure Team (and founded M.A.S.K. as an anti-Cybertronian deterrent team, with parts of their technology reverse-engineered from their captive, Decepticon triple-changer Blitzwing), Colton himself was on of a few Joe Team members who got replaced by Dire Wraiths (Rom's sworn enemy), Baron Karza found that Microspace was created by Micronus Prime (one of the 13 Primes of Cybertronian lore), and Ore-13, a powerful energy source created by Decepticon Shockwave and seeded on Earth during the ice age, is what drives the plot, as ''everyone'' is trying to use it. [[spoiler:It's eventually revealed that Mayhem, Karza and the Dire Wraiths were working together to exploit Ore-13 for their own ends, only for Karza to go OneWingedAngel when he absorbs a bunch of Ore-infused Wraiths with his "enerchange" ability and takes down Mayhem; it ultimately takes the Micronauts, Rom, Soundwave, Matt Trakker and Mainframe working together to bring him down.]]
*** The follow-up ''ComicBook/{{Revolutionaries}}'' takes it further, bringing in all sorts of obscure concepts and tying up dangling plot threads from previous IDW titles, including various ''G.I. Joe''-related villains - Baron Ironblood from ''Action Force'' (the British 80s counterpart to ''G.I. Joe''), General Krieger from ''WesternAnimation/SgtSavageAndHisScreamingEagles'' (a mid-90s attempt to reboot the ''G.I. Joe'' line), Iron Klaw from ''WesternAnimation/GIJoeExtreme'', and the Transformers from ''Hearts of Steel'' (a universe where the Transformers landed on Earth in the 1800s and got {{Steampunk}} bodies).
** More toy lines related to the ''Transformers'' multiverse include ''[[WesternAnimation/ChallengeOfTheGoBots GoBots]]'', ''WesternAnimation/{{Robotix}}'', ''Rock Lords'', and ''Beastformers'', the Japanese version of ''Battle Beasts''.
* Creator/ShotaroIshinomori's later ''Manga/SkullMan'' manga incorporates his earliest concept for the titular character of ''Kamen Rider'', monsters from said show, and Series/KamenRider himself, along with appearances of Joe Shimamura from the anime ''Manga/{{Cyborg 009}}'' and cameos from ''Series/HimitsuSentaiGoranger'', ''Series/RobotDetective'', ''{{Inazuman}}'', and ''Series/{{Kikaider}}.'' A later anime version of ''Skull Man'' has a DownerEnding that connects it even more explicitly to ''Manga/{{Cyborg 009}}'': [[spoiler:Skull Man is defeated and turned into Black Ghost, the BigBad of ''009''.]]
* The OVA ''Manga/GiantRobo: The Day The Earth Stood Still'' and its companion manga ''The Day The Earth Burned'' incorporates practically ''all'' of Mitsuteru Yokoyama's work, including the first magical girl ''Manga/SallyTheWitch'', the tokusatsu show ''Iga No Kagemaru'', the eponymous giant robots, and historical characters from both the ''Literature/WaterMargin'' and ''Literature/RomanceOfTheThreeKingdoms''.
* {{Inverted|Trope}} with ''VideoGame/StarshipTitanic'' and ''Franchise/TheHitchhikersGuideToTheGalaxy''. Despite both featuring similar Starship Titanics which undergo similar events in similar settings, the game [[FridgeLogic explicitly states that they're different universes.]]
* ''TabletopGame/WitchGirlsAdventures'' is a [[TheVerse 'verse]] created almost entirely through Canon Welding. The 'verse [[BleachedUnderpants started as a fetish e-zine called "The Shrinking Sorceress"]] by MANGA GRAPHIX, dedicated to sorceresses transforming people into animals and inanimate objects. Later on, many of the same people went on to write ''Witch Girls Tales'', theoretically a comic about young witches getting into mischief with their powers, and several characters and concepts from MANGA GRAPHIX stories ended up in the new 'verse. Completely independently, a different author wrote a comic called "Princess Lucinda," about the titular princess' love for wickedness and transforming people over the slightest offense. The ''Witch Girls Adventures'' game was created as a team-up between Channel M (the reconstituted MANGA GRAPHIX) and Abby Soto (the creator of Princess Lucinda), using characters from "The Shrinking Sorceress" (including some that hadn't yet appeared in ''Tales''), ''Witch Girls Tales'', and ''Princess Lucinda'' all in a single standalone universe.
* ''Manga/ReturnToLabyrinth'':
** The OEL manga sequel to the film ''Film/{{Labyrinth}}'' has cameos by Uncle Traveling Matt from ''Series/FraggleRock'' and the devils from the "Soldier and Death" episode of ''Series/TheStoryTeller'', establishing that these Creator/JimHenson Company works share a [[TheVerse Verse]].
** Fraggle Rock (the location) is basically a canon-welding tool, since it's established in the fourth season of the show that the Rock can magically link to many locations - some in our world, some in others. Uncle Matt also turned up in ''Film/TheMuppetsTakeManhattan'', and other creatures from the Rock have appeared as extras in Muppet productions throughout the 1990s. In turn, the Muppets share a universe with ''Series/SesameStreet''. Additionally, one creature occasionally seen in Fraggle Rock resembles Fizzgig from ''Film/TheDarkCrystal'', suggesting another link.
* The guest characters of the ''VideoGame/{{Soul|Series}}'' series imply that the series shares a multiverse with ''Franchise/TheLegendOfZelda'', ''Franchise/StarWars'', ''VideoGame/{{God of War|Series}}'', ''Manga/SgtFrog'', Creator/ImageComics (or at least ''ComicBook/{{Spawn}}''), ''VideoGame/TalesOfSymphonia'', and ''Franchise/AssassinsCreed''.
** The ''Soul'' series is also hinted to take place in the distant past of the ''VideoGame/{{Tekken}}'' universe due to the presence of [[LegacyCharacter Yoshimitsu]] in every installment of both series. Well, ''nearly'' every installment; the ''Soul'' series Yoshimitsu didn't debut until ''Soulcalibur'', and he is [[LegacyImmortality eventually succeeded by]] Yoshimitsu the Second in ''Soulcalibur V''.
*** WordOfGod indeed places the ''Soul'' series and ''Tekken'' in the same universe. The presence of ''Zelda'', ''Star Wars'', ''God of War'', Image Comics, and ''Assassin's Creed'' characters are non-canonical (although Lizardman's character profile in ''SCV'' seems to imply that [[spoiler:he ate Kratos]]). As for ''Tales of Symphonia'' and ''Sgt. Frog'', it's left ambiguous.
* Video game ''VideoGame/BlairWitchVolumeIRustinParr'' sets the original ''[[Film/TheBlairWitchProject Blair Witch]]'' movie and the video game ''VideoGame/{{Nocturne}}'', made by the same creators, in one world.
** And apparently the first ''VideoGame/BloodRayne'' game implies several times that it's set in the same world as ''Nocturne''.
* There is a crossover between ''Franchise/WonderWoman'' and ''Literature/FafhrdAndTheGrayMouser''. The latter's world was adapted into ''TabletopGame/DungeonsAndDragons'' setting. Of course, there was a fair amounts of retcons in Franchise/TheDCU and revised editions of D&D, but it's quite possible that the link establishing connection between the three still exist in some form.
** Thanks to the d20 edition of ''TabletopGame/CallOfCthulhu'' you can play as Dungeons and Dragons characters in Call of Cthulhu and introduce the Cthulhu Mythos into Dungeons and Dragons. It however doesn't stop there as the Call of Cthulhu sourcebook known as the ''Malleus Monstrorum'' not only mentions every major [[Franchise/CthulhuMythos Mythos]] entity, it also manages to throw in ''Film/TheThing1982'', the Martians of ''Literature/TheWarOfTheWorlds'', and ''Film/TheWickerMan1973'' and several of Creator/StephenKing's characters as avatars of Nyarlathotep.
** D&D's crossover with the Mythos and Nehwon goes back to the AD&D 1st Edition version of the ''Deities & Demigods'' {{Sourcebook}} published in 1980, along with the heroes of Arthurian legend and the deities of Michael Moorcock's world of Melnibone. The Cthulhu Mythos and Melnibonean material nearly brought down legal action from Creator/{{Chaosium}}, which had the game license rights to both at the time, and so they were left out of subsequent print runs since Creator/{{TSR}} didn't want to provide a reference to a competitor in the publishing credits. Obviously, copies of this first printing are hard to find.
* Creator/RaymondEFeist's ''Literature/TheRiftwarCycle'', set in [[http://www.rpg.net/columns/designers-and-dragons/designers-and-dragons13.phtml Midkemia,]] setting of RPG publisher Midkemia Press, who were also Raymond E. Feist's college role-playing buddies. [[note]]"While I was writing Magician, it occurred to me that it was stupid to be creating all of this stuff for Midkemia and creating a separate world called Crydee. So I asked them if they had any objections to me combining the two, turning Crydee into a duchy on the far coast of this empty area of the kingdom and tailoring my story around that. (Interview, ''[[http://www.sierragamers.com/uploads/24082/Interaction/016_InterAction_Volume_5_Number_4_Winter_1992.pdf InterAction Magazine - Vol. V Number 4 - Winter 1992]]'')"[[/note]] ''Literature/TheRiftwarCycle'' includes Sierra's ''VideoGame/BetrayalAtKrondor'' and its novelization.
* Creator/NeilGaiman's ''Literature/AmericanGods'' had a cameo from Delirium of the Endless from ''ComicBook/TheSandman''. Given the Endless' nature it is entirely vague if that means the book takes place in the Franchise/DCUniverse or just is part of the same multiverse.
* ''Creator/TeamFourStar'' connected their LetsPlay of ''VideoGame/DragonBallXenoverse'' to ''WebVideo/DragonBallZAbridged'' by way of AscendedFanon: namely, that their character Dumplin is a younger, less experienced Mr. Popo.

[[folder:Anime and Manga]]
* Manga creator Creator/GoNagai does this often with his various works, although ''Anime/MazingerZ'' and ''Anime/UFORoboGrendizer'' were already part of one continuity from Grendizer's get-go.
** ''Anime/ShinMazinger'' is quickly reaching a critical level of this, with a woman from ''Violence Jack'' turning out to be [[spoiler: Kouji Kabuto's ''mother''.]]
** ''Manga/ViolenceJack'' has incorporated ''Manga/{{Devilman}}'' and later ''Manga/DevilmanLady'' as taking place in one Universe [[spoiler:that resets itself and all main characters are really incarnations of Akira Fudou]]. And because the series is also DeconstructorFleet for all other Creator/GoNagai's manga, there are many theories incorporating them into it [[spoiler:in all incarnations, which is possible thanks to the nature of this world]]. Cameos and crossovers between his works are so often it's pretty easy. Then there's ''Devilman Grimoire'', where Jun Fudo and Aoi Kurosaki from ''Devilman Lady'' are shown to be teachers at Akira and Miki's school. They are also lovers. Alphonse and Himura, from the 1970s ''Devilman'' anime series, also feature.
* Gosho Aoyama's three main works ''Manga/DetectiveConan'', ''Manga/MagicKaito'', and ''Manga/{{Yaiba}}!'', have the tendency to merge into one universe. ''Magic Kaito'' was more or less put on hold in favor of ''Detective Conan'', but its characters occur so frequently in ''Detective Conan'' to be the latter's recurring characters. Although, Aoyama also drew the line: ''Detective Conan'' does not deal with the daily life of the ''Magic Kaito'' characters.
* The ''Franchise/{{Gundam}}'' franchise started off with only the Universal Century timeline under the auspices of creator Creator/YoshiyukiTomino. When he stepped away from the franchise in 1993, Sunrise introduced the concept of {{Alternate Universe}}s to allow new creators to explore their vision of Gundam without creating a ContinuitySnarl, resulting in the [[Anime/MobileFighterGGundam Future Century]], [[Anime/MobileSuitGundamWing After Colony]], and [[Anime/AfterWarGundamX After War]] timelines. Then Tomino returned for the 20th anniversary and created ''Anime/TurnAGundam'', set in the Correct Century timeline, which was eventually revealed to be the DistantFinale of ''all'' of Gundam, including the [=AUs=]. Afterwards came more Alternate Universes ([[Anime/MobileSuitGundamSEED Cosmic Era]], [[Anime/MobileSuitGundam00 Anno Domini]], [[Anime/MobileSuitGundamAGE Advanced Generation]], and [[Anime/MobileSuitGundamIronBloodedOrphans Post Disaster]]), with WordOfGod confirming that they're part of the timeline created by ''Turn A'' as well. Tomino's latest work, ''Anime/GundamReconguistaInG'', takes place in the Regild Century timeline, which is explicitly stated in-series as being the era that came after the end of the Universal Century. The sole exception to the rule is ''Anime/GundamBuildFighters'', which takes place in a TwentyMinutesIntoTheFuture setting where ''Gundam'' is a popular anime franchise. Presumably the same applies to ''Anime/ModelSuitGunplaBuildersBeginningG'', which is ''Build Fighters''[='=] [[SpiritualSuccessor spiritual precursor]].
* The mangaka group Creator/{{CLAMP}} has been known for self-crossovers for many years, but their twin series ''Manga/TsubasaReservoirChronicle'' and ''Manga/XxxHOLiC'' are meant to tie all their works--both present-day and fantasy--into a single continuity.
* One of ''Naruto Shippuden'''s final {{Filler}} arcs revealed that the reason Kaguya turned into a cruel warlord was that she [[spoiler:feared the arrival of Momoshishi and his subordinates, who were the villains of the eleventh (and canonical) film, ''Anime/BorutoNarutoTheMovie''.]]
* ''Anime/PrettyCureAllStars.'' 14 magical girls from 4 different continuities save the day. Awesome.
** The second All Stars-movie features 17 magical girls from 5 different continuities. From the previews it seems to feature some of the different baddies, too.
*** ''All Stars DX 3'' ups the number to 21 from 6 continuities and the brand-new New Stage brings it to a grand total of 28 from 7. It overlaps with RememberTheNewGuy as a lot of Cures that show up in one movie weren't in the movie before that.
*** ''All Stars New Stage'' delivers a {{Retcon}} of sorts now stating that 23 magical girls from 6 different continuities saved the day. Then 5 more from the 7th hopped in and it was madness.
** Interestingly, it seems that ''Anime/SmilePrettyCure'' is attempting a bit of a Canon Weld experiment themselves - an episode midway through reveals that Yayoi's mother works for Fairy Drop, the store owned by [[Anime/HeartcatchPrettyCure Erika Kurumi's]] mother. And said mother is mentioned, at least by last name.
* Eiichiro Oda re-used Ryuuma, a character from his one-shot manga ''Monsters'', as a (zombified) villain in ''Manga/OnePiece'' and his home country was mentioned to be part of the New World (the second half of the Grand Line). He later confirmed that ''Monsters'' was incorporated into the backstory of the setting.
* ''Manga/MahouSenseiNegima'' reveals that all of Ken Akamatsu's major works exist in the same universe. The ties between Negima and ''Manga/LoveHina'' are obvious with Setsuna being a Shinmeiryuu swordswoman, which is lead by the Aoyama family from ''Love Hina''; the reference to ''Manga/AILoveYou'' is found in a single panel, although it's kinda important, as [[spoiler:the protagonist of that series is implied to have written the code that enables [[RobotGirl Chachamaru]] to have a soul]].
* Before he gave the world ''Manga/DragonBall'', Creator/AkiraToriyama's first popular series was a comedy called ''Manga/DoctorSlump'', about a robot girl and the slob scientist who created her causing havoc in a weird place called Penguin Village. About a year into ''Dragon Ball'', Toriyama had Goku visit Penguin Village and meet most of the ''Slump'' cast, thus joining the two series into one universe. This was mostly done as an attempt to use ''Dr. Slump'''s popularity to help increase readership of ''Dragon Ball'', as it wasn't the huge hit it would eventually become yet. In contrast, the crossover has had the opposite effect in later years: many fans, especially outside of Japan, only know the ''Dr. Slump'' cast because of their guest spot on ''Dragon Ball''. It's gotten to the point that Arale's made it into at least three Dragon Ball video games as a playable character! ''VideoGame/DragonBallZBudokaiTenkaichi 3'', ''VideoGame/DragonBallOrigins'' and ''Revenge of King Piccolo'', to be precise. The first one also caused a good amount of rejoicing for those who knew her.
* The Creator/AkiraToriyama manga ''Pola and Roid'', ''Tomato, Girl Detective'' and ''Wonder Island'' connect to ''Dr. Slump'' through cameos. The manga ''Dub and Peter 1'', ''Escape'', ''Go! Go! Ackman'', ''Kajika'', ''Kintoki'', ''Nekomajin''/''Nekomajin Z'', and ''Sand Land'' might all take place in the ''Manga/DragonBall'' universe (Galactic Patrol of ''Manga/JacoTheGalacticPatrolman'', ''Jiya'' and ''Sachie-chan Guu!!'' fame is confirmed to take place due to its ending).
* ''Anime/DragonBallSuper'' is an odd example, since while it's specifically meant to be a sequel to the original ''Manga/DragonBall'' manga rather than the anime, various anime-only {{Filler}} moments get directly referenced. Gregory, an anime-only character, is present, Android 18 gets pissed when 17 accidentally calls Marron "Maron", Krillin's girlfriend from the Garlic Jr. filler arc, and when Krillin is surrounded by ghosts of the various villains they've fought over the series, [[FreakyFridayFlip Captain Ginyu in Bulma's body]] also appears, something that also never happened in the manga. On the other hand, Gohan at one point talks to a group of bus hijackers he stopped in the manga, but not the anime, and various continuity errors, such as the different depictions of hell in the ''Z'' anime and ''Super'' exist if one tries to connect them directly.
* The canons of ''VisualNovel/{{Tsukihime}}'', ''VisualNovel/FateStayNight'' (plus others) are generally grouped together and called the Franchise/NasuVerse. There's rarely direct crossover of the characters, except in [[VideoGame/BattleMoonWars spin-off]] [[VideoGame/MeltyBlood games]] and non-canonical side-comics. WordOfGod on each canon's characters respective power levels in relation to each other ([[MemeticMutation can Shiki kill Servants?]]) is [[FlipFlopOfGod conflicting]]. Even better: it is canonical in the series that alternate timelines exist in which different events took place, and that travel between them is possible (albeit ''extremely'' difficult, this being the Second Magic), so it can be said that ''all'' routes of ''all'' materials are canonical in one universe or another. Except ''LightNovel/KaraNoKyoukai'' which, by WordOfGod, explicitly isn't in the same universe as Tsukihime.
* Creator/LeijiMatsumoto is notorious for this, with ''Manga/GalaxyExpress999'', ''Anime/CaptainHarlock'', ''Anime/QueenMillennia'', and ''Anime/SpaceBattleshipYamato'' crossing over to various degrees, not always following a consistent continuity.
* Endings of ''Manga/GetterRobo Armageddon'' and ''New Getter Robo'' [[spoiler:in which Armageddon versions of Ryoma, Hayato and Benkei and New version of Ryoma ends in WarriorHeaven, alongside countless Getters, fighting unknown monsters]] has hinted that all Getter's separated continuities (two mentioned above, Creator/KenIshikawa's manga continuity, ''Getter Robo DASH'' manga and anime ''Getter Robo Go'' and ''Shin Getter Robo Vs Neo Getter Robo'') might exist in the same Multiverse.
* Madhouse Studios anime adaptations of four Creator/MarvelComics' titles - ComicBook/XMen, ComicBook/IronMan, ComicBook/{{Wolverine}} and ComicBook/{{Blade}} - are set in one Universe, confirmed both by WordOfGod from Marvel and the same Wolverine appearing in all four anime.
* ''Anime/GaoGaiGar FINAL'' has blink-and-you'll-miss-it cameos of characters from ''Anime/{{Betterman}}'', establishing those two series takes place in one Universe.
* ''Anime/{{REDLINE}}'' does this by making main characters from two different anime - Miki and Todoroki from ''MoleBrothers'' and Trava and Shinkai from ''TravaFirstPlanet'' - participating in the eponymous race.
* Several years ago, Hidenori Kusaka and Satoshi Yamamoto worked on a short ''VideoGame/PokemonRanger'' manga that was only released online. As it turns out in the Platinum arc of ''Manga/PokemonSpecial'', the events that occured in that online comic are indeed canonical.
* ''Anime/TimeBokan'':
** ''Anime/YattermanNight'' has the cast encountering characters (or in some case, blatant {{Expies}})) from various other shows produced by Creator/TatsunokoProduction. One episode even has Galina and Alouette driving the [[Anime/SpeedRacer Mach 5]]!
** This seems to be tradition for ''Anime/{{Yatterman}}'': the original and 2008 series crossed over with several Tatsunoko shows, and even placed them in a "Tatsunoko Kingdom" where ''all'' Tatsunoko characters appeared to reside in during one OVA.
* Eiji Ohtsuka has demonstrated that his horror manga ''Manga/MPDPsycho'' and ''Manga/TheKurosagiCorpseDeliveryService'' share a continuity thanks to the character Sasayama, who appears as a police officer in the former and as a social worker, at a later stage of his life, in the latter.

[[folder:Comic Books]]
* Creator/JackKirby is the TropeCodifier.
* The [[Franchise/TheDCU DC]] and [[Franchise/MarvelUniverse Marvel]] universes were born from this trope; originally, the titles published by each company did not overlap, but over time, cameos, {{Crossover}}s, and inside references combined to form the comic books into one big, interconnected web. That's not even counting the Amalgam universe. Since ''DC Vs. Marvel'' in 1996, it's revealed all crossovers were canonical -- FromACertainPointOfView. [[note]]The different universes and realities occasionally touch, causing them. Access' job is to make sure they don't stick.[[/note]]
** Mind, Marvel started this with the first issue of ''ComicBook/SpiderMan''. And even before that, Marvel started this 21 years earlier in the Timely Comics era, when Human Torch faced off against Namor the ComicBook/SubMariner for the first time. They teamed a few more times over the next few years, and some of the less prominent characters occasionally got involved. Then, in 1946, Timely launched the All-Winners Squad, teaming up existing characters like ComicBook/CaptainAmerica, the Human Torch, and the Sub-Mariner (among others).
** DC started it in All-Star Comics #3 with the Justice Society's first meeting. To this day, it's generally accepted that the Justice Society is the first-ever example of a super hero team lasting longer than a single issue in comics history.
** DC has also historically made a habit of assimilating the characters of other comics companies into their multiverse - Quality Comics (Uncle Sam and the Comicbook/FreedomFighters, ComicBook/PlasticMan, Comicbook/{{Blackhawk}}), Creator/FawcettComics ([[ComicBook/{{Shazam}} Shazam, Captain Marvel and the Marvel Family]]), Creator/CharltonComics (ComicBook/CaptainAtom, ComicBook/BlueBeetle, ComicBook/TheQuestion), Creator/WildStorm (ComicBook/TheAuthority, ComicBook/WildCATs), Creator/MilestoneComics (ComicBook/{{Icon}}, ComicBook/{{Hardware}}, ComicBook/{{Static}}) and Franchise/ArchieComics' Red Circle superhero characters. Generally, these characters start off in alternate universes, and then some sort of universal crisis reboots the DC Universe yet again, merging the universes.
** That said, sometimes the welding isn't permanent, as with the Red Circle characters, who eventually returned to Archie.
** ComicBook/DCRebirth saw the welding of Watchmen and the DC main universe.
* ''ComicBook/{{Shazam}}'' and ''Kid Eternity'' are a particularly interesting example. DC acquired the rights to both from separate comic companies. Eventually, they realized that ''Shazam'''s Freddy Freeman and the [[NoNameGiven nameless]] Kid had remarkably similar back stories--both were [[RaisedByGrandparents raised by a grandfather]] who died in a boating accident caused by Nazis, which also resulted in the grandson getting superpowers activated [[ByThePowerOfGrayskull by saying a magic phrase]]. As a result, Freddy and "[[GivenNameReveal Kit Freeman]]" were revealed to be brothers.
* ''Creator/ImageComics'' is an interesting case.
** Originally, all of its titles took place in a shared universe. Over time, the original Image partners focused on their own corners of the Image Universe, causing the continuity to split into several distinct sub-continuities. The ''Shattered Image'' crossover made the split official. But Image partners still occasionally "borrowed" each others' characters, so the sub-universes still interacted. As new, non-partner creators become more prominent in Image Comics, they started building universes of their own, and they occasionally used the Image partners' characters. For example:
** Characters from Jay Faerber's creator-owned series (''ComicBook/NobleCauses'', ''Venture'', ''Firebirds'', and ''ComicBook/{{Dynamo5}}'') appear in each other's books all the time, creating a loose-knit "Faerberverse".
** Robert Kirkman's characters occasionally cross over in a similar fashion (and sometimes become supporting cast - especially in ''ComicBook/{{Invincible}}''). The Kirkmanverse and Faerberverse intersect at a number of points, especially The Pact mini-series. Other Image characters, such as ComicBook/SavageDragon and ComicBook/{{Shadowhawk}}, often pop up. ComicBook/{{Spawn}} didn't make an appearance until ''Image United'', which brought together characters of all of the current Image partners (Erik Larsen, Rob Liefeld, Todd [=McFarlane=], Marc Silvestri, Robert Kirkman, and Jim Valentino), as well as Whilce Portacio and several other creators.
** Angela from the ''Comicbook/{{Spawn}}'' universe jumped ship to the Franchise/MarvelUniverse at the close of ''Comicbook/AgeOfUltron''.
* Eclipse Comics' four-part crossover mini-series ''Total Eclipse'' brought together virtually all company-owned and creator-owned characters that the company published.
* ''ComicBook/TwoThousandAD'':
** The ''ComicBook/HarlemHeroes'' strip (about a basketball team with jetpacks in 2050) appeared to be totally unconnected to the 22nd centuy of the ''ComicBook/JudgeDredd'' universe until the son of one of the Heroes (John "Giant" Clay) joined the Judges (as Judge Giant).
** The ''ComicBook/JudgeDredd'' story "Hammerstein" suggested ''ComicBook/ABCWarriors'' was also set in the past of the Dreddverse, but later ''ABC Warriors'' stories contradicted this.
** ''Judge Dredd'' has also had crossovers with other ''2000 AD'' strips whenever the writers felt like it, most notably ''ComicBook/StrontiumDog'' and the story Helter Skelter (where Creator/GarthEnnis basically crossed ALL his favourite strips over with Dredd).
** Meanwhile, ''2000 AD'' stalwart Pat Mills has crossed over ''everything he's ever written for 2000 AD'' with each other. ''Invasion!/ComicBook/{{Savage}}'', ''ComicBook/{{Flesh}}'', ''Ro-Busters'', ''ComicBook/ABCWarriors'', and ''ComicBook/NemesisTheWarlock'' all slot together.
** Ian Edginton does the same thing with his ''2000 AD'' strips: both ''Stickleback'' and ''The Red Seas'' share a secret organisation, little mentions and character cameos abound, and the same brand of monster appears in ''Stickleback'', ''Ampney Crucis Investigates'', and ''Detonator X''.
** Even more Edginton crossovers: Sir William Ashbless, [[spoiler:immortal]] designer of the titular ship in ''Leviathan'' made a cameo appearance in ''Stickleback'' and his shipping company, White Hart Line, got name dropped in ''Ampney Crucis Investigates.'' Also a few locations have been repeated across the various strips at different periods in history.
** John Smith did a similar thing from the start in order to make his stories stand out: all his initial ''[[ComicBook/ThargsFutureShocks Future Shocks]]'' linked in to an organisation called Indigo Prime, and a couple of Indigo Prime agents also appeared in ''Tyranny Rex''. Indigo Prime then got its own series, and eventually crossed over with Smith's Creator/VertigoComics series, ''Scarab''.
* Creator/AlanMoore:
** He, as time has gone on, has turned ''ComicBook/TheLeagueOfExtraordinaryGentlemen'' into this, making vague references to the source material for ''Ozymandias'' and ''The Black Freighter''. Oh, sure, it's only references to the inspirations for them, and Moore would probably rather have his skin boiled than actually go further than that, but this is Creator/AlanMoore, ''there are no coincidences''. As an aside, Moore is a close friend to Moorcock, close enough that Moorcock has allowed Moore to put in some Moorcock characters into the ''League'' series free of charge.
** Back in the day, Alan Moore sketched out a unified ''Warrior'' timeline, the most notable aspect of which was that, in an AlternateUniverse where [[ComicBook/{{Miracleman}} Micky Moran]] never regained his memories and powers, Emil Gargunza went on to build Fate, [[Comicbook/VForVendetta Norsefire]]'s supercomputer. The timeline also established when all the "centuries in the future" strips happened in relation to each other, and introduced the Chronarchs, who Moore calls "Earth-2 [[Series/DoctorWho Time Lords]]", and who seem to be based at least partly on his own version of Gallifrey in the ''Magazine/DoctorWhoMagazine'' comic strip. Then Moore quit ''Warrior'' and the book collapsed before any of this could actually appear.
** Moore's ''ComicBook/{{Providence}}'' is an attempt to do this for all of Creator/HPLovecraft's stories, or at least the different cycles. Much like ''League of Extraordinary Gentlemen'', Moore is using Lovecraft's fiction to merge different stories and events into a single coherent verse. This includes "Cool Air", "The Horror at Red Hook", "Literature/TheShadowOverInnsmouth", "Literature/TheDunwichHorror", "Literature/TheColourOutOfSpace", "The Dreams in the Witch House", "Literature/TheThingOnTheDoorstep".
* Creator/FrankMiller's Franchise/{{Batman}} stories: ''Comicbook/BatmanTheDarkKnightReturns,'' ''ComicBook/BatmanYearOne,'' ''ComicBook/TheDarkKnightStrikesAgain,'' and ''[[ComicBook/AllStarBatmanAndRobinTheBoyWonder All-Star Batman and Robin]]'' were originally supposed to be in separate universes, with only ''Comicbook/BatmanTheDarkKnightReturns'' and ''ComicBook/TheDarkKnightStrikesAgain'' having any clear continuity with each other.
* [[http://www.bleedingcool.com/2009/10/01/the-mark-millar-tie-up-athon-spoilers/ This article]] suggests that all of Creator/MarkMillar's later Marvel works (''1985'', ''ComicBook/FantasticFour'', ''ComicBook/KickAss'', and ''ComicBook/OldManLogan'') is all interconnected. (Three of those are automatically canonical to each other anyway, of course, but ''Kick-Ass'' is more of a surprise.) Even ealier Millar established connections between three comics published by different companies - ''ComicBook/{{Wanted}}'', ''ComicBook/{{Chosen}}'' and ''ComicBook/TheUnfunnies''. The reason why at the end of ''Chosen'' [[spoiler:the media doesn't report the Antichrist's miracles is that they're controlled by supervillains from ''Wanted'']]. And Troy Hicks from ''Unfunnies'' [[spoiler:helped Satan rape the Antichrist]]. Never published ''Run!'' was supposed to be set in that world too.
* Creator/GrantMorrison's ''ComicBook/AllStarSuperman'' and ''ComicBook/DCOneMillion'' seemed to be tied in the same continuity.
** Of course, Creator/GrantMorrison is one of the architects of [[http://www.hyperborea.org/flash/hypertime.html Hypertime]] (the other being Creator/MarkWaid) which posits that it is all true. Under this concept, the events of ''DC vs. Marvel'' exist somewhere in continuity.
** Almost all of Morrison's DC works are tied to each other, ''as well to the [[RealLife real world]]'', forming a big "Morrisonverse". Here's how it goes: In ''All-Star Superman'' Superman creates the infant universe Qwewq. In ''[[Franchise/JusticeLeagueOfAmerica JLA]]'' we see the heroes discover (a version of) Qwewq. Both in ''ASS'' and in ''JLA: Confidential'' we see that Qwewq actually contains "our" Earth, i.e. a realistic Earth with no superheroes. The final Morrison-penned issues of ''Comicbook/DoomPatrol'' and ''Comicbook/AnimalMan'' take place in a realistic world with no superheroes (and they both share the same colour scheme, meaning it's the same world in both), which is presumably Qwewq, i.e. "our" world. In ''ComicBook/SevenSoldiers'' we find out the ultimate fate of Qwewq (or at least one version of it). ''ComicBook/FinalCrisis'' (which takes place in the same universe as ''JLA'') refers to Bleed (the "sea" that separates different universes in the DC multiverse) as "ultramenstruum", and the same term is used is ''Comicbook/TheInvisibles'', implying that the Invisibles universe is a part of the larger DC multiverse. If we accept that Qwewq is "our" universe, this means our universe exists inside a larger universe populated by superheroes. Both ''Comicbook/FlexMentallo'' and ''ComicBook/TheFilth'' feature the "real" world to which superheroes from outside this world burst in; thus, the real world in both these comics could be (a version of) Qwewq. And then a huge chunk of the [[Franchise/{{Batman}} Damian Wayne]] stories written by Morrison that take place in the [[TwentyMinutesIntoTheFuture not too distant future]] were revealed to be set in the past of ComicBook/DCOneMillion and ends with Damian training Terry [=McGinnis=] from WesternAnimation/BatmanBeyond to become his successor. Lastly it also seems that DC One Million takes place in the future of All Star Superman as Solaris and Kal Kent appear and happens to be the story of how Superman ended up having to fix the sun. To sum it up, almost all of Morrison's major works for DC are welded together, though admittedly some of the links between them are vague.
* When Semic Comics, a French comic publisher, decided to revive the characters it inherited from defunct ''Editions Lug'', editor Jean-Marc Lofficier set out to link over 2000 largely unrelated characters from just about every comic book genre into a single continuity. Some characters had to be revamped fairly drastically to fit in, and a few had to be revamped to avoid duplication.
* In ''ComicStrip/NonSequitur'', Wiley frequently used four separate sets of recurring, originally nameless, characters: a silent {{Everyman}} who'd observe some of the comics' less absurdist strips, a ''VideoGame/LeisureSuitLarry''-ish barfly, a snarky BrattyHalfPint girl and the Sunday-only diner owner "Offshore" Flo (and her tall-tale telling patron, Eddie). Gradually, the characters started interacting: the Everyman and the barfly were seen hanging out at the bar, the girl and Flo would occasionally be seen reacting to something from the Everyman's radio talk show. Eventually, Wiley brought all these elements together to form a central cor: Joe (the everyman) and Bob (the barfly) are brothers, Danae (the little girl) and her little sister are Joe's daughters and Flo is Joe and Bob's mother. Eddie remains "just" Eddie.
* In one Super Special ''ComicBook/ArchieComicsSonicTheHedgehog'', Sonic finds himself universe hopping to the WesternAnimation/SonicUnderground universe. In the 25 Years Later storyline, he names his children after his counterpart's siblings.
** In the same Super Special, Sonic and Sally end up universe hopping again and teaming up with ComicBook/SabrinaTheTeenageWitch, making the Sonic comics part of the Archie Comics multiverse, not just under their label.
** In another, the Freedom Fighters universe hop into the Image Comics universe, meeting Spawn, Savage Dragon, the Maxx, and Shadow Hawk.
** [[ComicBook/SonicTheHedgehogMegaManWorldsCollide The Mega Man comic started being welded into the Sonic comic canon as well.]]
* The villain of ''Comicbook/{{Asterix}} and the Magic Carpet'' briefly refers to his cousin Comicbook/{{Iznogoud}}.
* One issue of ''Comicbook/{{PS238}}'' reveals that it and ''ComicStrip/{{Nodwick}}'' are set in the same world, though taking place in different "Heroic Ages."
* 2017's ''The Scream and Comicbook/{{Misty}} Special'' did this in a couple of strips. Maxine in ''The Return of Black Max'' passes by the Sentinels from ''The Return of the Sentinels'', and the title character of ''Death-Man'' encounters aged versions of classic Fleetway characters Leopard from Lime Steet, Pete's Pocket Army, Deathwish, Steel Commando, Paddy [=McGinty's=] Goat, Doctor von Hoffman, the Iron Major, and The Dwarf, as well as the [[{{legacy character}} successors]] of Doctor Sin and Thunderbolt the Avenger.
* This is the crux of the plot for ''ComicBook/RoboCopVersusTheTerminator'': the technology that turned Alex Murphy into Franchise/RoboCop leads to Skynet gaining sentience and the creation of the Franchise/{{Terminator}}s.

[[folder:Fan Works]]
* ''FanFic/DigimonTrinity'' is a WhatIf that treats ''Anime/DigimonTamers'' as a sequel to ''Anime/DigimonAdventure'' and ''Anime/DigimonAdventure02'' rather than a ContinuityReboot, and thus, several examples of this exist:
** Kari is the teacher of Takato's class, rather than Nami Asaji.
** Yolei and TK, now under his true name of Takeru, have replaced Yamaki and Riley as agents of Hypnos.
** Sora and Matt are friends of Rika's family, due to Sora's fashion designer job and Rumiko's modeling.
* ''FanFic/DigimonChildrenOfTime'' combines the events of all six ''Digimon'' anime ((''Anime/DigimonAdventure'', ''Anime/DigimonAdventure02'', ''Anime/DigimonTamers'', ''Anime/DigimonFrontier'', ''Anime/DigimonSavers'', and ''Anime/DigimonXrosWars'') into one coherent continuity.
* The ''Final Fantasy RPG'' collaborative UsefulNotes/{{Roleplaying}} group combined ''VideoGame/FinalFantasyI'', ''VideoGame/FinalFantasyIV'', and ''VideoGame/FinalFantasyVI'' into one world, with characters crossing over from ''VideoGame/FinalFantasyV''. The NURPG spinoff was set on an alternate world version of ''VideoGame/ChronoTrigger'', and had characters cross over from ''VideoGame/FinalFantasyVII'' and all sorts of different media. A third spinoff was based on ''VideoGame/MegaManClassic''. This resulted in creating a fanon [[TheMultiverse multiverse]].
* ''ComicBook/{{Supergirl}}'' fanfic ''Fanfic/HellsisterTrilogy'' combines several separate and unrelated stories to flesh Satan Girl’s backstory out: Red Kryptonite making Supergirl grow a second head in ''ComicBook/ActionComics'' #283, the birth of Satan Girl in ''Adventure Comics'' #313 and the appearance of ''[[ComicBook/DemonSpawn Nightflame]]'' in ''Adventure Comics'' #421.
-->She had been manifest two other times, in different guises. Once, Supergirl had been given a contentious second head by Red Kryptonite. That was her first known instance of consciousness. She had been bitchy then, but not evil. Not yet refined enough for that.\\
The second time had been her first outing as Satan Girl, and it had almost worked. Except for that stupid group of animals, it would have. Kara and the Legion bitches would have been dead, and she would have been extant from that time to this. She was evil then, but she hadn't really killed anyone.\\
The third time, she was manifest as Nightflame, a giant sword-wielding woman who wreaked havoc in San Francisco, born of her old identity and some other elements added from Kara's psyche, amplified by a mage who existed in a sub-atomic universe on a world somehow within Kara. Even she was confused by that one, and didn't comprehend it all. She supposed that the sword and magic came from those Moorcock novels that Kara had run through once. That time, she had very nearly taken over Kara's body. Only the girl's undeniably strong will, and some psychic help from her friend Geoff, had withstood her. So she had gone back into nonexistence.
* ''Film/StarTrekNemesis'' actually ''{{Jossed}}'' several elements of Creator/DianeDuane's earlier ''Literature/{{Rihannsu}}'' novels, and ''Fanfic/EmaelMosekhesailho'' spends some time welding them back together, among other things making ''Nemesis'' character Senator Tal'Aura a member of Kaveth Ship-Clan.
** Generally speaking, many ''Star Trek'' fans do the same in their own stories, as the ''Literature/{{Rihannsu}}'' version of the Romulans [[BetterThanCanon is generally considered better than the canonical version]]. Even ''VideoGame/StarTrekOnline'' (that, as you know, is an official production) does it to some degree.
* ''Fanfic/SoulEaterTroubledSouls'': Both ''Manga/SoulEater'' and its spinoff ''Manga/SoulEaterNot'' are featured prominently in this story. Similar canon-welding occurs with the anime and manga of each source material.
* ''Fanfic/HauntedMansionAndTheHatboxGhost'': The fanverse includes several properties (fanmade and official alike) welded together into a single continuity, even when no continuity was intended from the authors.
* ''Fanfic/GuardiansWizardsAndKungFuFighters'' has a bit of this going on, as a result of the universes of ''WesternAnimation/JackieChanAdventures'' and ''WesternAnimation/{{WITCH}}'' being [[MergedReality merged together]]:
** A Heart of Earth gave [[TheChosenOne Ben Shui's spirit]] its reincarnation cycle.
** Tarakudo and his Generals once invaded Meridian, but were sealed away by its Heart and ancient heroes.
** Daolon Wong is now in the service of Prince Phobos.
** Theodore Riddle, an enemy of the Guardians from the [[ComicBook/{{WITCH}} comics]], is one of the leaders of the Dark Hand.
* ''Fanfic/PokemonStorySinnohJourney'':
** Takes place in the anime-verse, but the narration references Sinnoh's Route 205, a game-verse concept.
** Furthermore, Aaron’s hometown of Metropolis Town is said to be in Orre. Marian and later May are well aware of the region despite being anime characters.
* ''FanFic/InnocenceAndExperience'' blends DC's Post-Crisis continuity with the events of ''WesternAnimation/YoungJustice'' to get its time travel-crossover story, in which Damian is inadvertently sent back in time to meet the Team just after the events of New Years Eve. The fact that Dick is unaware of the fact that he would eventually pass the mantle of Robin over to Damian is the primary source of friction in the comic.
* The ''Fanfic/EarthsAlienHistory'' timeline has multiple examples, courtesy of mixing numerous franchises and making them work as a singular setting:
** The [[Franchise/MassEffect Reapers]] destroyed the {{Precursors}} of both the [[Webcomic/{{Drive}} Vinn]] and the [[Literature/{{Footfall}} Fithp]], as well as the original homeworld of the [[Film/IndependenceDay Harvesters]] (thus rendering them nomadic).
** The ComicBook/IronMan armor is based off of that used by [[Franchise/{{Metroid}} Samus Aran]].
** Series/{{Torchwood}} is in the place of [[Franchise/StarTrek Section 31]].
*** Speaking of Torchwood, it turns out that the alien attack on Queen Victoria that led to their formation in this universe was by the [[Series/StargateSG1 Goa'uld Osiris]].
** Mars is home to multiple species, including the [[Literature/WarOfTheWorlds Mollusks]], the various [[Literature/JohnCarterOfMars Barsoomians]], the [[Creator/DCComics Whites and Greens]], and the [[Series/DoctorWho Ice Warriors and Osirians]].
** The technology of the [[Film/PacificRim Jaegers]] is based on that of [[WesternAnimation/SymBionicTitan Galalunan]] battle armors; later developments lead to the creation of Franchise/{{Gundam}}s. Also, genetic links are found between the Kaiju and the creatures of Mutraad, though the truth of this is never fully established.
** Speaking of Galaluna, General Modula's coup is in this universe backed by the Mekon, who does so to [[FalseFlagOperation frame the Salarians]] for it, both to directly deny [[TheAlliance TeTO]] another potential ally and to taint their relationship with the Citadel.
** Mankind's first Warp flight, which attracts the attention of the Vulcans, is here the ''Commodore Perry'', on its way to the [[Literature/WorldWar Race's Home]].
** The H'urq, who invaded Q'onos in the Klingons' ancient past, were actually Collectors.
** The [[VideoGame/{{Turok}} Lazarus Concordance]] are renegade Time Lords.
** [[Film/StarTrekIITheWrathOfKhan The Genesis Project]] is inspired by the [[Series/{{Defiance}} Votans']] own terraforming technology.
** The powers of ComicBook/BlackCanary are actually inherited from [[Series/PowerRangersDinoThunder Kira Ford]].
** The [[Series/{{Supergirl2015}} DEO]] combines aspects of its canon form with [[Series/DoctorWho UNIT]] and [[Franchise/MarvelCinematicUniverse SHIELD]].
* ''Fanfic/TheMelindaChronicles'': In addition to introducing [[Franchise/{{Highlander}} immortals]] to the [[Franchise/SonicTheHedgehog Sonicverse]], the fic wields elements from EU sources like [[WesternAnimation/SonicSatAM SatAM]]/[[ComicBook/ArchieComicsSonicTheHedgehog Archie Sonic]] into the game universe, with things like Kai explicitly being Wolfpack Nation in cultural origin. Elements of the Highlander universe aside from immortals existing are also present with Melinda mentioning Duncan and Connor by name and alluding to Methos.

[[folder:Films -- Live-Action]]
* Present in horror films a long, long time. In the Franchise/UniversalHorror series, ''Film/FrankensteinMeetsTheWolfMan'' triggered the tendency to pile on the monsters, insisting that Dracula, the Wolf Man and Frankenstein's Monster all existed in a common universe. This does not work well with continuity (''Film/TheWolfMan1941'' takes place in the present day while the others happen in a dimly-characterized past), but they didn't care much by that point (Universal's horror films of the 40s are strikingly dumber and more juvenile than those of the 30s).
* Predating even these examples: Fritz Lang's ''Film/TheLastWillOfDrMabuse'' (1933). Nominally a sequel to Lang's ''Film/DrMabuseTheGambler'' (1922), it also incorporates Inspector Lohmann from ''Film/{{M}}'' (1931) as the main protagonist. Blending the super villain from a pulp thriller with the hero of a police procedural works surprisingly well. Well enough that a 1960s revival of the Mabuse series retains Lohmann as its protagonist.
* In all honesty ''Franchise/{{Alien}}'' and ''Franchise/{{Predator}}'' were never really meant to part of the same universe. The Xenomorph head seen near the end of ''Film/Predator2'' was only meant as a reference to the non-cannon comic book series that was being worked on at the time. It wasn't until the connection was made completely canonical in ''Film/AVPAlienVsPredator''. Hints placed by Creator/RidleyScott in ''Film/{{Prometheus}}'' and in the latest re-edit of ''Film/BladeRunner'' suggest that they (and of course the rest of the ''Film/{{Alien}}'' franchise, and transitively ''Franchise/{{Predator}})'' share the same continuity.
* Any {{Kaiju}} film made by made by Creator/{{Toho}} is prone to become part of the ''Franchise/{{Godzilla}}'' universe. In fact some of Godzilla's most recognized enemies came from their own movies, including Film/{{Mothra}} and Film/{{Rodan}}. Even the [[Film/{{Godzilla 1998}} 1998 version of Godzilla]] is canonical due to him getting his butt whooped by the real Godzilla in ''[[Film/GodzillaFinalWars Final Wars]]''.
** Before ''Final Wars'', in ''Film/GodzillaMothraKingGhidorahGiantMonstersAllOutAttack'' (aka ''GMK''), there's another acknowledgment of the US ''Godzilla'' that works even better at integrating it into canonicity. In this film's continuity, Godzilla hasn't been seen since [[Film/{{Gojira}} the original 1954 attack on Tokyo]], and many people no longer remember what he looked like. It's said that there was a reported Godzilla attack in New York a few years earlier, but it's unconfirmed whether it was the real Godzilla. This fits perfectly with the US film, wherein Japanese characters identify the creature as "Gojira." Indeed, ''GMK'' has characters mistaking another monster (Baragon) for Godzilla, which may be an intentional retcon for how the creature in the US film got misidentified that way.
** In an interesting note, there is a Toho version of Film/KingKong existing in the Godzilla universe that first appeared in ''Film/KingKongVSGodzilla'' and later got his own movie called ''Film/KingKongEscapes''. The Toho version of King Kong is a very altered version, though, considering that he has more raw power, is intelligent enough to learn and adapt to situations, and lives on Mondo Island instead of Skull Island. [[RuleOfCool Oh and he is able to draw power from electricity]].
* ''Creator/FullMoonFeatures'' also has done this a lot over their existence. Complete with direct CrossOver like ''Film/{{Dollman}} vs Film/DemonicToys'', characters cameoing in other movies and to the point the ''Film/GingerdeadMan'' is now a regular recurring character in the''Film/ EvilBong'' series now that his series is done. Ironically there also was ''Film/PuppetMaster vs Film/DemonicToys'' which while originated by Full Moon was licensed out and made by Syfy, which Charles Band now counts as non-cannon both to the studio and the series.
* And besides all the above, other crossover horror films such as ''Film/FreddyVsJason'', ''Film/SadakoVsKayako'' and Film/LakePlacidVsAnacaonda are all further examples.
* Creator/QuentinTarantino has created a largely common universe of his films by including subtle crossreferences (for instance, characters commonly refer to others; Mr. White mentions Alabama and Mr. Blonde has Scagnetti as a parole officer, Vic Vega and Vincent Vega are brothers, etc.) and cameos, but he says that his movies are divided into ''two'' universes.
** The first is an [[spoiler:alternate reality where Hitler was shot down in a theater causing Americans to be obsessed with pop culture and extremely violent]], which consists of ''Film/PulpFiction'', ''Film/ReservoirDogs'', ''Film/TrueRomance'', ''Film/InglouriousBasterds'', ''Film/DeathProof'' and possibly ''Film/DjangoUnchained''.
** The second is a universe that takes place in Tarantino movies that are supposedly released in both the real world and the main Quentin Tarantino Universe, which consists of ''Film/KillBill, Film/FromDuskTillDawn, Film/NaturalBornKillers'', and possibly ''Film/{{Machete}}'' and ''Film/PlanetTerror'' because of cameos of Earl and Edgar Mcgraw in both movies. Interestingly, the title character in ''Film/{{Machete}}'' appears in another of Creator/RobertRodriguez's films...''Film/SpyKids''.
** Tarantino has also stated that Django and his wife Broomhilda are intended to be the ancestors of [[Film/{{Shaft}} John Shaft]].
* An interesting example occurs with the ''Film/{{Cloverfield}}'' franchise, which ended up having to be welded to ''itself''. The first film was a standalone found-footage movie, and despite numerous [[SequelHook Sequel Hooks]], nothing came of them for a very long time. The next time the series' name showed up was ''Film/TenCloverfieldLane'', a film which had practically nothing to do with the original and felt very much InNameOnly; rather than a found footage film, ''10 Cloverfield Lane'' was a psychological horror film, and dealt with a human villain [[spoiler:and an alien invasion]] rather than a giant monster attack. WildMassGuessing abounded on how these two films actually connected. It wasn't until the third film, ''Film/TheCloverfieldParadox'', that [[TheMultiverse the true relationship between entries]] becomes clear; said film also [[spoiler:serves as a prequel to the original ''Cloverfield'', and sees Clover itself (or another member of the same species) appear at the very ending]].
* The 1980s/90s series of Superman and Batman films made no reference to each other and given their vast differences in tone might have been assumed to take place in very different universes (despite their comic books having long been from the same universe), until Bruce mentions that the circus Dick had performed with "must be halfway to Metropolis by now" in ''Film/BatmanForever''. That didn't prove it for everyone, though (Metropolis might just be another city in Batman's world, die-hards argued); it wasn't until [[Film/BatmanAndRobin the next movie]] that the canon welding was made official, in ''the most cringe-inducing way possible.''
--> '''Robin:''' ''(checking out the Batmobile)'' I want a car. Chicks dig the car!
--> '''Batman:''' ''(turning to camera)'' This is why Superman works alone.

* The ninth ''Literature/FightingFantasy'' gamebook, ''Literature/CavernsOfTheSnowWitch'', took the player on a tour of the major locations from two of the previous books (''Literature/WarlockOfFiretopMountain'' and ''Literature/ForestOfDoom''), establishing that they all took place in the same land of Allansia. (It also name-checked a character from ''Forest of Doom''.) The monster manual ''Literature/OutOfThePit'' then expanded this world: Allansia and The Old World, the setting for the ''Sorcery'' series of gamebooks, were two continents on the world of Titan.

* Fantasy author Creator/MichaelMoorcock gradually connected almost every single character he'd created into a MythArc revolving around the concept of the [[CosmicPlaything Eternal Champion]].
** Moorcock's ''Series/DoctorWho'' novel ''The Coming of the Terraphiles'' features a ''Captain'' Cornelius, who may or may not be another aspect of the Eternal Champion (much like [[Literature/TheCorneliusChronicles Jerry Cornelius]]) which ties the Eternal Champion into the Whoniverse as well![[note]]Moorcock has said that Captain Cornelius was created because he was told he couldn't use Jack Harkness. Whether this makes Captain Jack the Eternal Champion is an open question, but it's fun to think it might.[[/note]] There's also a Second Aether, referencing Moorcock's Second Ether sequence which also takes place in the Eternal Champion continuity.
** Moorcock also wrote some stories set in Creator/AlanMoore's Creator/AmericasBestComics Universe, characters from which later appeared in Elric comics; Elric himself briefly met ComicBook/ConanTheBarbarian in an early issue of Conan's Creator/MarvelComics series.
* In the 1980s, Creator/IsaacAsimov wrote a series of novels that linked his ''Robots'', ''Empire'', and ''Literature/{{Foundation}}'' novels into a single continuity. He also even went so far as to in ''Literature/FoundationAndEarth'' suggest (via throwaway reference in dialogue) a tenuous connection between the Robots/Empire/Foundation series and an otherwise seemingly unrelated, comparatively obscure time-travel novel, ''Literature/TheEndOfEternity'', which he wrote in the 1950s (interestingly enough, if they ''were'' in the same continuity, the end of the novel would effectively have caused the ''entirety of the events in the rest of the series'', because said ending [[spoiler:revolves partly around allowing humanity to expand into space instead of mouldering on Earth]]). He also threw in a reference to his standalone novel ''Nemesis'' in one of the later Foundation books, despite the fact that Nemesis and the Robots/Empire/Foundation books taking place in the same universe makes no sense whatsoever (not even the space-travel physics work the same way). Though it may have been a literal reference to his ''novel''.
** ''Psychohistorical Crisis'', a CaptainErsatz filled FanSequel to the Foundation series written by Donald Kingsbury, {{retcon}}s a number of aspects of the Foundation series, and also ties in Asimov's otherwise unrelated short story ''Literature/{{Nightfall}}''. Since it's not "official", it's free to ignore the Robots connection, and does so.
* The final novels in Creator/AnneRice's ''Literature/TheVampireChronicles'' tie Lestat's story into that of Literature/TheMayfairWitches.
** Actually, they were tied together much before that, notably by the Talamasca (introduced in ''Queen of the Damned'' and later a key player in both the vampires and witches novels) and a few common supporting characters like Aaron Lightner. In other words, the Witches novels avowedly take place in the same world as the ''Vampire Chronicles'' from day one, though their interactions increase substantially over time. Hints in ''The Vampire Lestat'' also indicate that Rice's least-liked novel, ''The Mummy,'' also shares a continuity with these series.
** The novel ''The Queen of the Damned'' establishes that witches and spirits are real. ''Memnoch the Devil'' claims that God, the angels, and TheDevil are all real.
** However, despite Lestat having actually met Christ, Rice insists that her biographical novels recounting the life of Jesus are not part of the same continuity.
* Creator/JRRTolkien:
** ''Literature/TheHobbit'' was not, at the time of its writing, intended to be in the same continuity as ''Literature/TheSilmarillion'', which Tolkien regarded mainly as personal recreation and had as yet no intent of publishing. Despite this, he couldn't help throwing in a few [[ShoutOut names and locations]] that referenced ''The Silmarillion''. When he began writing the sequel that would become ''Literature/TheLordOfTheRings'', he went whole-hog and moved ''The Hobbit'' to Middle-Earth, ''The Silmarillion'' becoming the BackStory of the novels. In fact, the ring that Bilbo found was originally just an ordinary, harmless magic ring and nothing more, and Gollum, having no motive to kill Bilbo, happily led him to safety at the conclusion of the riddle game. It wasn't until ''The Lord of the Rings'' was being written that Tolkien decided that it was ''the'' ring, and he revised the Bilbo-Gollum encounter in order to make it more sinister. The in-universe explanation for the altered narrative is that Bilbo wrote the first version while under the influence of the ring as he wanted to conceal the actual circumstances of his acquiring it. The revised, true version was written later, after he was no longer in the ring's grasp.
** Tom Bombadil, Goldberry and Old Man Willow originally appeared in a poem published in 1933. They had no connection to Middle-Earth until the writing of ''Literature/TheLordOfTheRings'' was in progress, and that didn't turn them into anything more significant than a WackyWaysideTribe.
* Creator/RobertAHeinlein did this towards the end of his career, incorporating all his previous stories (often with radically different universes) into one meta-universe, thanks to a handy trans-dimensional device invented by one of his characters. Then he brought the ''Literature/JohnCarterOfMars'' series in, and the [[Literature/LandOfOz Oz books]], and eventually ''[[http://en.wikipedia.org/wiki/World_as_Myth all fiction ever created]]''.
** Though he did give preference to the ones he liked, and especially those written by authors with whom he was personally acquainted; one of the transdimensional 'jumps' involved taking the characters into the Literature/{{Lensman}} universe created by his friend, Creator/EEDocSmith.
*** He even threw in some real people: the characters of ''Literature/TheNumberOfTheBeast'' run into [[Creator/LewisCarroll Charles Dodgson]] while in Wonderland, and near the end of the novel, it's mentioned that [[Creator/RobertAHeinlein Bob]], [[Creator/ArthurCClarke Arthur]], and [[Creator/IsaacAsimov Isaac]] should be showing up for a big meeting soon.
** Nearly all main characters he ever wrote are in one scene at the end of ''Literature/TheCatWhoWalksThroughWalls''.They try to [[spoiler:recover Mycroft Holmes, whose death was perhaps the biggest TearJerker Heinline ever wrote. Towards the end the characters are aware they are in a story, and find the Author to be a bastard...]]
* Creator/LarryNiven originally had two continuities: the first was the "slowboat" stories of early colonization of space by humanity (featuring the novels ''Literature/WorldOfPtavvs'', the Gil Hamilton stories, and ''Literature/AGiftFromEarth''), while the second featured faster-than-light travel and aliens (featuring the stories of Beowulf Shaeffer, Louis Wu, and the ''Literature/{{Ringworld}}''. And then he wrote his short story "A Relic of the Empire", which combined the two continuities and created the ''Literature/KnownSpace'' universe.
* The first novel in Creator/TerryPratchett's ''Literature/NomesTrilogy'', ''Literature/{{Truckers}}'', takes place in the (real) town of Grimethorpe, but in the later books the Store is relocated to Blackbury, which is also the setting of the Literature/JohnnyMaxwellTrilogy.
* Creator/EdgarRiceBurroughs had Literature/{{Tarzan}} travel to the underground world of Literature/{{Pellucidar}} in order to rescue the hero of the series. ERB weaved together the continuity of his books in other ways.
** The character Jason Gridley is introduced in ''[[{{Literature/Pellucidar}} Tanar of Pellucidar]]'', meets Literature/{{Tarzan}} in ''Tarzan at the Earth's Core'', and appears as part of the frame story in ''[[Literature/JohnCarterOfMars A Fighting Man of Mars]]'' and ''Literature/PiratesOfVenus'', linking together Burroughs' four main series.
** The technology for the Moon mission from ''Literature/TheMoonMaid'' was Barsoomian in origin.
** Tarzan is a supporting character in ''The Eternal Lover'', whose central character is the sister of the hero of ''The Mad King''; thereby bringing those otherwise non-series novels into the fold.
* Terry Brooks' ''Literature/{{Shannara}}'' series was always established as being set a fantasy world that formed AfterTheEnd of modern civilisation. His ''Literature/TheGenesisOfShannara'' series is set during the collapse of civilisation, and establishes the Four Lands as the future of his ''Literature/TheWordAndTheVoid'' novels.
* What Creator/AugustDerleth called the "Franchise/CthulhuMythos" (a term never used by Creator/HPLovecraft and only by Derleth after Lovecraft's death) originated from cross-references by Lovecraft between his own stories and that by other writers. Lovecraft, not Derleth, referenced passages from the Necronomicon, other forbidden books, or placing offhand comments during the expository monologues, about various {{Eldritch Abomination}}s having no bearing on the current story. Specifically, ''Literature/TheDreamQuestOfUnknownKadath'' ties most of his early standalone [[ShortStory short stories]] into the Dreamlands Cycle, and also brings in "Pickman's Model" and the Randolph Carter stories. The Dreamlands Cycle is ultimately linked to the so-called Cthulhu Mythos, though a few stories, such as the early "Literature/{{Dagon}}", ''may'' be outside the grand continuity. Several other authors have tied them together, notably Creator/AugustDerleth and Creator/ClarkAshtonSmith. Even the demonic race beneath the Earth from "Literature/TheRatsInTheWalls" appears to be referenced in "Literature/TheWhispererInDarkness".
** Creator/ClarkAshtonSmith's Xiccarph and Zothique series were not originally connected to the "mythos" in Smith's own writings.
** Lovecraft and others tied works by earlier writers he did not personally know. For example, Creator/RWChambers' ''Literature/TheKingInYellow'' (referenced in "The Whisperer in Darkness"), to the work of Creator/ArthurMachen (the Aklo language) and Creator/LordDunsany (Bethmoora).
** Though they never met in person, Lovecraft and Creator/RobertEHoward were pen pals and some of their letters discuss plans to combine their respective universes, but their [[AuthorExistenceFailure untimely deaths]] prevented this from [[WhatCouldHaveBeen being made a reality]] beyond a few vague hints in various stories. What's especially interesting is that magic and other supernatural elements are vital to most Howard stories, whereas Lovecraft's are notable for the complete absence of anything without a scientific rationale.
* Beginning with ''Literature/{{It}}'', Stephen King began tying many of his novels into ''Franchise/TheDarkTower'' series, to the point that every single novel he wrote during the early 2000s was somehow related to the epic. The process included bringing back a character he PutOnABus (literally) in ''Literature/SalemsLot'' and {{retcon}}ning the BigBad from ''Literature/TheStand'' into the Crimson King's [[TheDragon Dragon]]. (Indeed, the Crimson King himself made his first appearance outside ''The Dark Tower'' series.)\\\
From ''Literature/{{Desperation}}'' (1996) to ''Literature/FromABuick8'' and ''Everything's Eventual'' (2002), 100% of King's fiction output (six novels and two story collections) tied into ''Franchise/TheDarkTower'' (at least retroactively). These were bookended by ''Literature/WizardAndGlass'' in 1997 and the conclusion of ''The Dark Tower'' series in 2003-04. Plus the aforementioned incorporation of everything back to ''Salem's Lot'' and ''Literature/TheStand'', written before ''Literature/TheGunslinger''.\\\
And lest we forget, ''Salem's Lot'' takes place in the same city as ''Jerusalem's Lot'', an earlier short story, confirmed to be in the Franchise/CthulhuMythos. Therefore, ''The Dark Tower'' series is part of the Mythos by extension. Oh and as mentioned above {{Transformers}}, Series/DoctorWho, Franchise/SherlockHolmes, and pretty much everything else on this page has crossed over with the Cthulhu Mythos.
** It's also been established that if there's anyone in a King story with the initials R.F., they're probably a very particular person: [[spoiler:Randall Flagg, the BigBad of ''Literature/TheStand'', The Eyes of the Dragon (as Flagg, no first name), and the Crimson King's [[TheDragon Dragon]].]] Except for (presumably) Rudy Foggia of ''The Jaunt'', who is quite dead at the beginning of the story.
** ''Literature/{{It}}'' also contains an appearance by Charles Pickman, from the Creator/HPLovecraft story ''Pickman's Model'' -- which ties it to all the Lovecraft stories mentioned below. King's next novel, ''Literature/TheTommyknockers'', not only crossed over with ''It'', but also tied in several of King's other novels, including ''Firestarter'' and ''Literature/TheTalisman''.
** Also, the books ''Dolores Claiborne'' and ''Gerald's Game'' refer to each other as the female protagonists of the books have a psychic link, having times when they suddenly get the feeling that this other person, who they don't know, is somehow in danger.
** ''Literature/{{Misery}}'' refers to ''Literature/TheShining'' at one point, when Annie mentions the ruin of the Overlook Hotel.
* Tony Hillerman once had two series, one featuring Navajo cop Jim Chee and one featuring Navajo cop Joe Leaphorn. There is now only the Leaphorn & Chee Mysteries.
** Though to be fair, from the beginning the Chee stories (which came second) would reference Leaphorn and characters and events from his stories--they just weren't featured in the same books for a while.
* Before he's done, F. Paul Wilson's ''Adversary Cycle'' bids fair to weave in practically every book and short story the man has ever written.
* Creator/MercedesLackey's assorted UrbanFantasy stories seem to be set in different continuities, until mention is made of the west coast elfhames (from the ''Bedlam's Bard'' series) in the ''Literature/{{SERRAted Edge}}'' novels, and of Tannim, the mulleted protagonist of the [=SERRAted=] Edge novels appearing as a bit character in his teens in ''Literature/JinxHigh'', a Diana Tregarde investigation.
** Since ''Jinx High'' was Tannim's first appearance, and the ''Bedlam's Bard'' events were namechecked in the first [=SERRAted=] Edge novel, this one was evidently intended from the start, or nearly so.
* Kate Elliott has confirmed that her new ''Crossroads'' trilogy of fantasy novels is actually a fictional story within the context of her earlier ''[[Literature/NovelsOfTheJaran Jaran]]'' series of SF novels.
* Creator/PeterFHamilton retconned several of his earlier SF short stories to be set in the same universe as his immense, later ''Literature/TheNightsDawnTrilogy'' and published them in a collection called ''A Second Chance at Eden''. However, he has avoided this phenomenon elsewhere and has created no less than three distinct SF universes existed at similar points in history, making it impossible for them to coexist in the same continuity.
* Creator/AlastairReynolds did something similar with several of his early SF short stories, retrofitting them into his ''[[Literature/RevelationSpaceSeries Revelation Space]]'' series of books and publishing the results as a collection called ''Galactic North''.
* Creator/GuyGavrielKay's ''Literature/TheFionavarTapestry'' presents the world of Fionavar as so significant that echoes of it appear in the mythologies of every other world in TheMultiverse. His subsequent stand-alone novels ''Literature/{{Tigana}}'' and ''Literature/TheLionsOfAlRassan'', although each set in a different world, each has a moment showing that to be true. ''Literature/{{Ysabel}}'' is more overt, actually featuring several characters from the ''Fionavar Tapestry'' later on.
* The Creator/PeterDavid novel ''Howling Mad'' mentions Mayor Penn, who is the returned King Arthur from ''Literature/KnightLife''.
* A particularly confusing example is ''The Well of Lost Plots'', which ties the world of ''Literature/ThursdayNext'' into a book ([[Literature/NurseryCrime now a series]]) that Jasper Fforde wrote ''first'', but which was published ''afterwards'' (''The Big Over Easy'', originally ''Nursery Crimes''), and does so by establishing it as fictional within the Nextiverse, although, like all works of fiction, Thursday can enter it, and spends most of the book inside it, being ultimately responsible for its odd mix of genres. Everyone follow that?
** To further confuse things, the ''Thursday Next'' stories are themselves fictional within the ''Nursery Crimes'' series.
* Creator/AgathaChristie's AuthorAvatar Ariadne Oliver seems to tie several of her series together. She originally appeared in the [[Literature/ParkerPyneInvestigates Parker Pyne]] stories (as did Miss Lemon). Then she became established as a Literature/HerculePoirot character, starting with ''Cards On the Table'' (which also featured Superintendent Battle, who'd previously appeared in the two novels starring Bundle Brent). Then she was the main character in the 1961 novel ''The Pale Horse'', which also featured the vicar's wife from the Literature/MissMarple novel ''The Moving Finger''. And in ''Murder in Three Acts'', Poirot meets Mr Satterthwaite, who previously appeared in ''Literature/TheMysteriousMrQuin'' collection of short stories. Literature/TommyAndTuppence are also linked, since the same slightly unhinged old lady appears in ''The Pale Horse'', the Miss Marple novel ''The Sleeping Murder'', and the Tommy and Tuppence novel ''By the Pricking of my Thumbs'', despite ''Partners in Crime'' having them refer to Poirot as a fictional character. Then again, ''Partners in Crime'' mentions Poirot, but not ''Agatha Christie'', and the novel that Tommy references is ''The Big Four'', one of the ones narrated by Hastings, so maybe it was, in-universe, written by Hastings, Watson-style.
** Tommy and Tuppence can also be linked to the others through a mysterious character who is only referred to as Mr. Robinson. This character appears with Poirot in ''Cat Among the Pigeons'', Marple in ''At Bertram's Hotel'', and Tommy and Tuppence in ''Postern of Fate''. He also appears in ''Passenger to Frankfurt'', which does not feature any of Christie's series detectives.
* While Creator/KimNewman has seeded connections between his books since the beginning, the short story "Cold Snap" seems to be a concentrated effort to tie them ''all'' together. A "Literature/DiogenesClub" story (and therefore featuring characters whose AlternateUniverse selves appear in the ''Literature/AnnoDracula'' novels) it adds characters from his early work such as ''Jago'', and even features the villain from his ''Series/DoctorWho'' novella ''Time And Relative''.
** Under the pseudonym Jack Yeovil, Newman wrote a number of books based on Games Workshop properties. ''Krokodil Tears'', one of the ''Literature/DarkFuture'' books, had its BigBad have a vision of an alternate version of himself as the Big Bad from his Vampire Genevieve series of ''Warhammer'' books.
* Creator/KimNewman isn't the only author to tie his personal [[TheVerse Verse]] into the Franchise/{{Whoniverse}}. Iris Wildthyme was a character in Paul Magrs' MagicRealism novels, before he revealed she was an extremely eccentric Time Lady.
** Iris Wildthyme, in her appearances in novels and audios, occasionally interacts with an organisation called MIAOW, The Ministry for Incursions And Other Wonders (simultaneously a parody of ''Series/{{Torchwood}}'' and ''Series/DoctorWho'''s UNIT). This organisation has also turned up in his Brenda and Effie series of novels set around Whitby. Characters from his Literature/EighthDoctorAdventures novel ''Mad Dogs and Englishmen'', his AudioPlay/BigFinishDoctorWho audio drama ''The Boy That Time Forgot'', and the ''Pheonix Court'' series that featured the original version of Iris have also appeared in this series. A character from one of Magrs' Tenth Doctor novels also reappeared in an Iris Wildthyme short story, along with a character from the Brenda and Effie series.
* Creator/HRiderHaggard's novel ''She and Allan'' brought together Ayesha from ''Literature/{{She}}'' and Allan Quatermain from ''Literature/KingSolomonsMines''.
* Creator/EEDocSmith's ''Literature/{{Lensman}}'' series of novels was originally 4 books long (initially published in serial form in an SF magazine). In the late 1940s or early 1950s, he took an early work of his named ''Triplanetary'' and retrofit it in with the rest of the ''Literature/{{Lensman}}'' universe. He wrote an additional novel, ''First Lensman'', to bridge the gap between the two storylines.
* Creator/JulesVerne did this quite a bit:
** Most famously, he welded ''Literature/TheMysteriousIsland'' with his earlier books ''Literature/TwentyThousandLeaguesUnderTheSea'' and ''Literature/InSearchOfTheCastaways'' by adding Captain Nemo from the former and Tom Ayrton from the latter to the cast of characters. (However, doing so opened a few [[PlotHole plot holes]], not to mention that the time period doesn't quite match.)
** ''Literature/RoburTheConqueror'' mentions the cannon from ''Literature/TheBegumsMillions''. (Insert inevitable joke about "[[IncrediblyLamePun Cannon Welding]]" here.)
* Creator/DavidGemmell has stated that all his books take place in the same world, despite covering vastly different territory, such as a low-magic fairly standard fantasy world (''Literature/{{Drenai}}'' saga), a post-apocalyptic world (''The Jerusalem Man'') and our own world (an Arthurian duology and a duology set in ancient Greece). (Those last three are explicitly connected by the plot device of the [[Literature/StonesOfPower Sipstrassi stones]].)
* L. Frank Baum, the author of ''Literature/TheWonderfulWizardOfOz'', also wrote [[Literature/LandOfOz Oz sequels]] and non-Oz works of fantasy. Through several {{Crossover}}s, he established that all of them take place in the same magical continent, called Nonestica.
** ''WesternAnimation/TheLifeAndAdventuresOfSantaClaus'' is arguably in continuity with them, too. An important part of the Oz mythos is that Lurline, Queen of the Fairies, enchanted Oz to make it a fairyland. The other book also features a fairy queen named ''Zurline.'' Fans are still unsure if they're supposed to be the same character.
* Leslie Charteris introduced Inspector Teal in the novel Daredevil featuring Storm Arden before Teal appeared in the Saint series.
* Creator/PoulAnderson's [[Literature/PolesotechnicLeague Nicholas van Rijn stories]] and Literature/DominicFlandry stories weren't, originally, part of the same universe. But a bit of prodding by fans, and he wrote some bridging so that now they are both part of the ''Literature/TechnicHistory''.
* Creator/DaleBrown has done this. Rebecca Furness and Daren Mace, characters originally in the non-Patrick [=McLanahan=] book ''Chains of Command'', joined the main continuity in ''Battle Born'' and ''Warrior Class'' respectively. The eponymous space station of ''Silver Tower'', thought a victim of CanonDiscontinuity because of its long absence from his books, joins the main continuity in ''Strike Force''. TheDragon of non-Patrick [=McLanahan=] book ''Storming Heaven'', Gregory Townsend, is DragonAscendant BigBad of main continuity title ''The Tin Man''.
* Creator/IainBanks, in his mainstream (non-SF) literature has said he doesn't do sequels/prequels; though he did include one subtle crossover in ''Complicity'': Cameron's friend Al, an engineer he met on a paintballing weekend, is Alexander Lennox, recovered from his car-crash in ''The Bridge''.
* All of Creator/ChristopherMoore's varied books appear to take place in the same verse, whether the setting is modern suburban California or Israel in Jesus's time. Various characters make appearances outside of their respective novels, like angels and vampires and fruit bats. Of course, whether this is actual canon ''welding'' or just his [[TheVerse Verse]] depends on whether Moore had the broad strokes sketched out from the start or just made it up as he went (and tied it together afterwards)!
* Creator/PhilipJoseFarmer took this to the extreme in his creation of the Wold Newton Universe. His novels ''Tarzan Alive'' and ''Doc Savage: His Apocalyptic Life'' link the two heroes' respective families to the same event, the meteor strike in Wold Newton, Yorkshire, England, on December 13, 1795. Other stories, both by Farmer and other writers, have expanded the Wold Newton universe to demonstrate links to Literature/TheScarletPimpernel, Franchise/SherlockHolmes, Literature/TheSpider, Literature/JamesBond, Literature/NeroWolfe, [[Literature/TheMalteseFalcon Sam Spade]], Radio/TheLoneRanger, Franchise/TheGreenHornet, and even Franchise/StarTrek.
** In a way, his series of books beginning with ''To Your Scattered Bodies Go'' could be considered the logical conclusion of this trope, as he intentionally designed a world in which he could bring in any character from any story written by anyone.
* Creator/MadeleineLEngle first connected her "Kairos" and "Chronos" series when Canon Tallis from Kairos novel ''The Arm of the Starfish'' appears in Cronos novel ''The Young Unicorns''; several characters from each series would cross over later.
* In ''The Art of Detection'', Laurie R. King welds her wildly successful series about [[Literature/MaryRussell Sherlock Holmes' female apprentice]] to her lesser-known series about a modern San Francisco cop. The novel is a serious MindScrew, as Sherlock Holmes appears to be simultaneously real and fictional in it.
* Creator/SimonRGreen's series The {{Literature/Nightside}}, Literature/SecretHistories, and Ghostfinders take place in the same world. And constantly [[ShoutOut reference]] each other. There are also very strong connections to his Deathstalker, Forest Kingdom, and Hawk and Fisher series. And all his other writings.
** In the latest Nightside novel there's even a perspective-flipped recreation of a scene from a Hawk and Fisher novel, of the duo waiting at a tavern to meet Razor Eddie.
* An [[WhatCouldHaveBeen unreleased]] series of novels (''Alien Exodus'' and ''The Human Exodus'') in the Franchise/StarWarsExpandedUniverse would have done this between ''Franchise/StarWars'', ''Film/THX1138'', and ''Film/AmericanGraffiti''. The novel would have had descendants of the characters from the latter two works warp across time and space to ALongTimeAgoInAGalaxyFarFarAway and become the first humans in that place.
* Narita Ryohgo wrote links establishing that his three series of light novels - ''LightNovel/{{Baccano}}'', ''LightNovel/{{Durarara}}'' and ''Vamp!'' - all take place in one universe. For example, Shizuo from ''Durarara'' mentions getting into a fight with person strongly implied to be one of the ''Baccano!'' characters.
* It's not clear if this was intended from the start, but a minor character in the Starbuck series (set in the American Civil War) by Bernard Cornwall was revealed in the second book to be the son of Richard Sharpe, the hero of the {{Sharpe}} series, Cornwall's earlier and more famous series set in the Napoleonic Wars.
* Neil Munro wrote two series of short stories for the ''Glasgow Evening News'': ''Erchie, My Droll Friend'' about a Glaswegian waiter, and ''Para Handy, Master Mariner'' about a steamboat going up the West Coast of Scotland. When Erchie needs to take a ship to his daughter's wedding, naturally it's Para Handy's ''Vital Spark''.
* Andrzej Pilipiuk has connected his Literature/JakubWedrowycz stories with his more serious trilogy called ''Kuzynki'' (''Cousins'') - Jakub is mentioned by name in second volume and makes a cameo in third, combined with the illustration to leave no doubt that this is indeed him. This is odd, because in first book of the trilogy Jakub is clearly fictional as one of the characters reads his books and considers them [[SelfDeprecation the evidence that modern Polish literature is terrible]].
* E. F. Benson's ''Literature/MappAndLucia'' series only came together with the novel of that title, which brought the characters of ''Miss Mapp'' together with those of two previous ''Lucia'' novels. Although not regarded part of the series ''per se'', another earlier novel ''Secret lives'' was also subsequently tied into the same continuity.
* Creator/AnneMcCaffrey:
** ''Pegasus In Flight'' and ''Pegasus In Space'' were written as {{Interquel}}s to officially merge the original ''Literature/ToRidePegasus'' with the later ''The Rowan'' and the rest of the ''Literature/TowerAndTheHive'' series into a single continuity.
** In one of the ''Literature/CrystalSinger'' novels, the protagonist travels in a BB Ship, the unique form of space travel featured in her earlier ''Literature/TheShipWhoSang''.
* Just about every book by Douglas Preston and Lincoln Child take place in the same fictional universe. They're probably best known for the Literature/AgentPendergast series, but even their non-Pendergast books share characters that tie in with one another. For example, one of their earlier books, ''Literature/{{Thunderhead}}'', introduced anthropologist Nora Kelly and featured William Smithback from their first Pendergast-related novels; Kelly was later made a recurring character in the Pendergast novels. Two Pendergast novels feature a wheelchair-bound profiler named Eli Glinn, he was introduced in an earlier novel entitled ''Literature/TheIceLimit'' and has later appeared in their new Gideon Crews series of novels. Mime, a hacker from the duo's second book ''Literature/MountDragon,'' has appeared in their later Pendergast novels.
* Several of Creator/PiersAnthony's works. The last book of the ''Mode'' series featured a brief trip to ''Literature/{{Xanth}}''. The 27th ''Xanth'' book included a visit to Phaze, a world from the ''Literature/ApprenticeAdept'' series.
* At the end of Creator/ChristopherAnvil's "War With The Outs" series, humanity learns that beyond the Outs' territory, space is controlled by two new alien races, the Stath and the Ursoids. Both of these had previously made appearances in his "Colonization" series, suggesting that the "War With The Outs" stories take place earlier in the same universe.
* Susanna Clarke published a short story where one of characters from ''Literature/JonathanStrangeAndMrNorrell'' visits village from Creator/NeilGaiman's ''Literature/{{Stardust}}'', making both stories take place in one world. As far as we know, this is still canonical.
* OlderThanRadio: French writer Creator/HonoreDeBalzac wrote a few independant novels and short stories before making recurring characters. He next made the project of making a study of human society and called his work ''The Human Comedy'' (in reference to ''The Divine Comedy'').
* OlderThanPrint:
** As the original versions of the stories have been lost and had to be speculatively reconstructed by scholars from the evidence of the various German and Scandinavian versions it is hard to tell, but it is quite clear that the ''Literature/{{Nibelungenlied}}'' is an amalgam of some quite different stories, and it is a matter of conjecture to decide when the welding of the elements occurred and which ones are to be attributed to the author of the Nibelungenlied. The story of the dragonslayer called Siegfried or Sigurd accounts for the first half of the main plot and the originally unrelated story of the death of the Burgundian kings at the hands of the Huns and their king Atli (Attila) for the second. The welding necessitated some changes, thus in the Scandinavian epics that contain just the Atli saga, the sister of Gunther, who is married to Atli, kills her husband to avenge her brothers. In the Nibelungenlied Kriemhild kills her brother using the army of her second husband Etzel (Attila) to avenge the murder of her first husband Siegfried.
** A canon-welding that does seem to be the idea of the writer of the Nibelungenlied is the inclusion of Dietrich and his knights in the finale, which fuses the Nibelungen story to the cycle of epics about Dietrich of Bern (Theoderic the Great). In that cycle Attila was presented essentially as a sympathetic character and generous host, not the kind of treacherous and cold-blooded killer as in the Atli sagas.
* George Mann's timeline of the ''[[Literature/AffinityBridge Newbury & Hobbes]]'' universe, at the back of ''The Casebook of Newbury & Hobbes'', includes his Franchise/SherlockHolmes novel, his ''Franchise/DoctorWhoExpandedUniverse'' work and ''Literature/TheGhost2010''.
* Creator/RobertEHoward did this a lot with his historical, horror and fantasy stories. Just to name a few examples: Literature/{{Kull}} was explicitly tied with Franchise/ConanTheBarbarian in the essay "The Hyborian Age". Both was tied with the historical-fantasy character Literature/BranMakMorn through the Kull-Bran crossover "Kings of the Night". The ring of Thoth-Amon, from the Conan stories, and worshipers of Bran are featured in Howard's modern horror stories, while both Bran and Kull are mentioned in one of his Turlogh Dubh O'Brien stories set in 1200's. It wouldn't be unreasonable to consider all of Howard's speculative fiction to be part of [[TheVerse the same verse]], even if Howard [[AuthorExistenceFailure never lived]] to point it out himself. And of course Howard and Creator/HPLovecraft making references to each-others in their works was the foundation of the Franchise/CthulhuMythos mention above.
* Members of a family named "Hempstock" have appeared in quite a few seemingly unconnected works by {{Creator/Neil Gaiman}}, including {{Literature/Stardust}}, {{Literature/The Graveyard Book}} and, most predominately, {{Literature/The Ocean at the End of the Lane}}. Death from {{ComicBook/The Sandman}} also gets a mention in Stardust.
* Indie author Royce Day's SpaceOpera ''Literature/TheRedVixenAdventures'' series and DieselPunk novella ''Prisoner of War'' both involve characters of a species that resemble humanoid foxes, feature characters who express similar religious and political views, and have a protagonist named Lord Rolas Darktail. But it wasn't confirmed as the same 'verse until ''Shadow of her Sins'' in the former series, which featured a minor character from Gerwart, an expy of Germany from "POW".
* There's a ''Literature/{{Flashman}}'' book where the title character (himself originally from ''Tom Brown's Schooldays'') encounters Literature/SherlockHolmes, Watson and their nemesis Tiger Moran.
* Creator/SteveAlten 's flagship ''Literature/{{Meg}}'' series and his seventh novel, ''The Loch'', became part of the same continuity with the latter book's sequel ''Vostok''.
* An unusual example of an author allowing someone else to Canon Weld their work: the ''Creator/ArthurCClarke's Venus Prime'' series by Paul Preuss have as their premise that many of Clarke's stories are set in a single Verse.
* Creator/RolandSmith linked his ''Jacob Lansa'' series with the standalone book ''Sasquatch'' by having Buckley Johnson, a character from the latter, appear in the third ''Jacob Lansa'' book. Lansa later appeared in ''Tentacles'', the second of the ''Cryptid Hunters'' series, and returned in the sequels alongside Dylan Hickock, the protagonist of ''Sasquatch''.
* The ''Literature/MarlaMason'' series' ninth book, ''Lady of Misrule'', reveals the author's previously stand-alone novel ''The Strange Adventures of Rangergirl'' to be set in the same universe.
* This, alongside ExecutiveMeddling, is the very origin of the ''Literature/{{Sandokan}}'' series: the author Emilio Salgari had originally written ''The Tigers of Mompracem'' as a stand-alone novel (and made clear in the ending that Sandokan was retiring from piracy) and planned a Tremal Naik series starting with ''The Mistery of the Black Jungle'' (that ended with a CliffHanger), but when reprints of the former outsold the latter by a fair margin the publisher asked Salgari to bring back Sandokan, and ''The Pirates of Malaysia'' starts with Kammamuri from ''The Mistery of the Black Jungle'' learning that Sandokan has unretired... [[OhCrap And the ship he's on has wrecked on his island]].
* The Literature/KateShugak novel ''Restless in the Grave'' features an appearance from Liam Campbell, the Alaska State Trooper protagonist of Dana Stabenow's other crime series, and other characters from his books. It may be a FullyAbsorbedFinale as there have been no Campbell novels since, and in ''Restless in the Grave'' [[spoiler:Liam has finally married his long-term love interest, and his mentor Moses is killed off at the climax.]]
* "The Dancing Floor", one of Creator/CherryWilder's last published works, combines elements from her Literature/{{Torin}} novels and her Literature/RhomaryLand novels, establishing them as part of the same future history.
* Keith Roberts' short story "Unlikely Meeting", published in ''Interzone'' #88, has teenage witch Anita meet Kaeti from ''Kaeti and Company''. Since Kaeti and company are a UniversalAdaptorCast anyway, he doesn't need to worry much about how it all fits together. (They've both read each others' books but it's not even particularly clear whether that's MutuallyFictional or ATrueStoryInMyWorld.)
* Creator/MatthewReilly novels often drop references to his other works. It kicked up a notch when a character from a Scarecrow novella appeared in the Jack West Jr books, [[spoiler:and up a few more notches when Scarecrow himself (protagonist of the eponymous series) shows up as a main character in the fourth Jack West Jr. novel, while references were made to other Scarecrow novels]].
* ''Literature/TheQuartet'': initially a standalone, ''Literature/The'' is about a boy named Jonas who lives in a FalseUtopia; he escapes at the end, along with baby Gabe, but [[AmbiguousEnding their fate is ambiguous]]. Another Creator/LoisLowry book, ''Literature/GatheringBlue,'' is set in a primitive village AfterTheEnd, but the characters eventually find a more advanced village with characters who ''might'' be Jonas and Gabe; WordOfGod initially said that it was up to reader interpretation whether the books were in the same universe. The following sequels, ''Literature/{{Messenger}}'' and ''Literature/{{Son}},'' slowly do away with any ambiguity.
* Creator/CliveBarker did this with ''Literature/TheScarletGospels'' distinctly bringing Harry D'Amour and ''Literature/TheHellboundHeart'' and ''Film/{{Hellraiser}}'' character Pinhead together, but there were hints in earlier books this may have been planned for longer.
* The ''Literature/FiveKingdoms'' series is set in the same {{Multiverse}} as that of the author's previous work, ''Literature/TheBeyonders.'' Two characters who died in the previous series show up in the world's shared afterlife in ''Five Kingdoms,'' and it's mentioned by those characters that the creatures known as torivors who trouble the Outskirts are a problem in their world, too.

[[folder:Live-Action TV]]
* Creator/RussellTDavies has suggested that Adam Mitchell's mum in ''Series/DoctorWho'', played by Judy Holt, may be the same person as Sister Mitchell in ''Series/ChildrensWard'', also played by Judy Holt, which would bring RTD's earlier programme into the Franchise/{{Whoniverse}}. He was ''probably'' joking.
* Rumors abound to this day that Patrick [=McGoohan=]'s Number 6 from ''Series/ThePrisoner'' is the same character as John Drake, his role in the earlier series ''Series/DangerMan''. [=McGoohan=] always denied it while other people involved in the show supported it, in what was probably a deliberate attempt to screw with the fans some more.
** It's been suggested that [=McGoohan=] tended to deny it solely because he didn't hold the rights to his previous role, and thus, establishing a direct connection could be considered copyright infringement and therefore actionable. His co-writer on the series has always claimed that it was definitely Drake.
* Although the Showtime revival ''Series/TheOuterLimits1995'' was an anthology show, it usually ended its seasons with money-saving clip shows tying multiple prior episodes together into a single continuity.
* ''Franchise/PowerRangers'' has gone through this a few times. While the first six seasons were all one storyline and the seventh (''Series/PowerRangersLostGalaxy'') was a direct sequel, each one past that has been self-contained; though many would make small references to prior seasons or at least eventually team up with the prior season's cast. Only two seasons (''Series/PowerRangersNinjaStorm'' and ''Series/PowerRangersRPM'') have been welded in after the fact, having nothing in themselves to connect to the rest of the franchise; and the third unconnected season (''Series/PowerRangersJungleFury'') has been welded into ''Series/PowerRangersMegaforce'''s CrisisCrossover. Also notable was that ''Series/PowerRangersLightspeedRescue'' welding itself to ''Lost Galaxy'' retconned the latter from TwentyMinutesIntoTheFuture to the present day. (''Lost Galaxy'' also once referenced the universal coordinates of [[Series/DoctorWho the Doctor's]] homeworld Gallifrey.)
* Later ''Franchise/KamenRider'' shows have taken steps to establish that the various characters created by Creator/ShotaroIshinomori (or at least AlternateUniverse versions of them) exist in the same universe. For example, characters from ''Series/SpaceIronmenKyodain'' appeared as the antagonists of one of the ''Series/KamenRiderFourze'' movies, while Inazuman appeared in the crossover movie between ''Fourze'' and ''Series/KamenRiderWizard''. ''Series/KamenRiderGaim'' also had a crossover with ''Series/{{Kikaider}}'' designed to promote the latter's new movie.
* The Disney Channel has done several crossovers with their live action series, so that [[Series/ThatsSoRaven psychics]], [[Series/WizardsOfWaverlyPlace wizards]], [[Series/TheSuiteLifeOfZackAndCody Tipton Industries]], [[Series/CoryInTheHouse President Martinez]], [[Series/ImInTheBand Iron Weasel]], and Series/HannahMontana all exist in the same [[Franchise/DisneyChannelLiveActionUniverse universe]].
* It's been more-or-less established that all Nickelodeon sitcoms beginning with ''Series/DrakeAndJosh'' all have some form of connection. Eventually enough crossovers happened for the Series/NickVerse to form. It is horrendously complicated by the fact that due to the way it came about, the actors and characters all exist alongside each other as real people. It includes ''Series/DrakeAndJosh'', ''Series/{{Zoey101}}'', ''Series/ICarly'', ''Series/{{Victorious}}'' and also causes ''Series/BigTimeRush'' and ''Series/TheNakedBrothersBand'' to enter the universe, via Creator/MirandaCosgrove showing up AsHerself on both those shows. This could somewhat more accurately (and awkwardly) be referred to as the Schneider-verse, for showrunner Dan Schneider.
* In the last episode of ''Series/SpinCity'' where Creator/MichaelJFox appears as a regular, it is suggested that the series takes place in the same universe as ''Series/FamilyTies''.
* Creator/StevenMoffat has welded a fair number of his series together over the years: ''{{Chalk}}'' contained frequent references to ''Series/PressGang'', and was in turn referred back to by ''Series/{{Coupling}}''; ''Series/{{Jekyll}}'' also referred to ''Series/PressGang'' and ''Coupling'' has references to ''JokingApart''. A list can be found [[https://sites.google.com/site/markandrich/themoffatverse here]].
* Lisa Kudrow, who played a quirky waitress on ''Series/MadAboutYou'', played Phoebe on ''Series/{{Friends}}''. It was later revealed they were twin sisters and Ursula (the waitress) became a recurring character. It was also revealed that Paul once lived in the apartment now occupied by Kramer on Series/{{Seinfeld}}.
** In the second season of ''Friends'', there was a brief crossover with ''Series/CarolineInTheCity''. Matthew Perry had a brief appearance on the Caroline episode as Chandler while Creator/LeaThompson had an appearance Caroline in the Friends episode. Expanding beyond those two, earlier that same season [[Series/{{Frasier}} Niles Crane and Daphne Moon]] appeared in one ''Caroline'' episode, and Frasier himself showed up in an episode of ''Series/{{Wings}}.'' Based on this logic, potentially every NBC sitcom that ran during the 90's takes place in the same world (and also proceeds to directly tie into the Westphall example below)
* Taking this to the extreme, due to various character cameos and crossovers, much of television history may take place in the mind of ''Series/StElsewhere'''s [[http://home.vicnet.net.au/~kwgow/crossovers.html Tommy Westphall]].
* Thanks to its importation of the ''Series/HomicideLifeOnTheStreet'' character JustForFun/JohnMunch and its numerous other crossovers (some involving him, others not), the ''Franchise/LawAndOrder'' [[CashCowFranchise franchise]] managed to bring in ''Series/{{NCIS}}'', ''Series/NCISLosAngeles'', ''Series/{{JAG}}'', ''Series/FirstMonday'', ''Series/InPlainSight'', ''The Beat'', ''Series/HawaiiFive0'', ''Series/TheWire'', ''Series/ArrestedDevelopment'', ''Series/TheXFiles'', ''Series/TheLoneGunmen'', and ''Series/{{Millennium}}'' all into a single universe. Also, ''Series/SesameStreet'', if you count Muppet versions of the character. All this also fits into the Westphall Hypothesis above.
** The scariest part of that link? ''The X-Files'' crossed over with ''Series/{{Cops}}'', a reality show, meaning that all those shows take place in our universe... Which is, of course, the imagination of an autistic boy with a snowglobe.
** NBC has also announced a crossover between ''Series/ChicagoPD'' and ''Series/LawAndOrderSVU'', this means that ''Series/ChicagoPD'' and ''Series/ChicagoFire'' are also part of this verse.
* There was a crossover between ''Series/MurderSheWrote'' and ''Series/MagnumPI'', and one between ''Series/MagnumPI'' and ''Series/SimonAndSimon''. Accordingly, all three are in the same universe.
* After ComicBook/JohnConstantine's [[Series/{{Constantine}} show on NBC]] was cancelled, a deal was struck to bring the character into ''Series/{{Arrow}}'' (and by extension, the Series/{{Arrowverse}}) for a guest spot, played by [[Creator/MattRyan the same actor]] using the same props and costumes, and thus importing that show into the larger franchise.
* ''Series/TheFlash2014'' has the multiverse as a large part of the arc of its second season. In the episode [[Recap/TheFlash2014S2E13WelcomeToEarthTwo "Welcome to Earth Two"]], two of the alternate worlds shown as ''Series/TheFlash1990'' and ''Series/{{Supergirl 2015}}''.
* All of Creator/{{Chespirito}}'s works have long been implied to be set in the same universe. Indeed, [[Series/ElChavoDelOcho El Chavo (del Ocho)]] and Series/ElChapulinColorado had met at least once.
* The 1970s {{ITV}} relaunch of TheBBC sitcom ''The Rag Trade'' had Peter Jones and Mirian Karlin reprising their roles from the sixties series, confirming they were in the same continuity ... and also added Olive from the same creators' ''Series/OnTheBuses''. (The character of Reg Turner [[TheDanza played by Reg Varney]] wasn't in the relaunch, so Olive didn't wonder why he [[YouLookFamiliar looked like her brother Stan]].)
* The ''Franchise/UltraSeries'': Originally, the [[Series/UltraQ first]] [[Series/{{Ultraman}} three]] [[Series/UltraSeven shows]] had minimal connections aside a few minor nods here and there. However, with ''Series/ReturnOfUltraman'', they were united into a singular continuity that followed for the rest of the Showa era, as well as with the Heisei series ''Series/UltramanMebius'' and ''Series/UltraGalaxyMegaMonsterBattle'' (which ends up creating a lot of contradictions as a result). Then, with the ''Franchise/UltramanZero'' movies, the remainder of the franchise was linked up with the Showa universe to create [[TheMultiverse a massive multiverse]], and then afterwards it gets super-confusing from there.

[[folder:Myths and Religion]]
* Myth/RobinHood went through several rounds of this, along with AdaptationDisplacement. Maid Marion (or "Marian"), Friar Tuck, and Alan-a-Dale were all characters from separate folk tales, and it was only later that Robin Hood stories had anything to do with Richard the Lionheart or Prince John.
* The ''Equivicatio Romana'' by which each of the gods and goddesses of the other pantheons the Romans encountered was said to be another name for the nearest equivalent in their pantheon--sometimes by a great deal of squinting.
* ''Euhemerism'' which postulates that the pagan gods and goddesses [[{{Demythtification}} were actually great heroes and heroines]] who lived long ago and whose reputations snowballed until they became gods.
** Herodotus one-ups Euhemeris by trying to equate Egyptian mythology and Greek mythology.
* The two Myth/ClassicalMythology stories that bring together large numbers of Greek heroes likely have their origins in CanonWelding: the Voyage of the Argo and the Calydonian Boar Hunt both feature characters like Herakles, Theseus, Bellerophon and so on. The fact that different versions of each story provide different lists of who was there pretty much confirms this.

* ''Pinball/ThePartyZone'' takes three of Creator/DennisNordman's games -- ''Party Animal, Pinball/ElviraAndThePartyMonsters,'' and ''Pinball/DrDude'' -- and gives them in a shared continuity they never had before.

[[folder:Tabletop Games]]
* An odd version of this exists in ''TabletopGame/DungeonsAndDragons''. Gods cross over from one campaign setting to another, spells exist under different names, and so on. Initially the settings were welded only by implication, mostly mythological crossovers (shared gods) and in the names of spells ("Bigby's Grasping hand", "Mordenkainen's Hound") indicating that divine beings and powerful wizards COULD travel between them, but providing no actual explanation. Later, the ''TabletopGame/{{Planescape}}'' and ''TabletopGame/{{Spelljammer}}'' meta-settings provided two (amusingly contradictory) explanations: in Planescape a stock-fantasy multiverse exists, with the added benefit of explaining where all the more biologically impossible elemental and evolutionarily improbable critters come from. Spelljammer is based on medieval cosmology, and adventurers can sail between the various crystal spheres in mighty magical craft riding currents in the luminiferous aether.
** There was also the [[InnBetweenTheWorlds World Serpent Inn]], which even links campaign settings which are explicitly not part of the Planescape/Spelljammer cosmology, such as ''TabletopGame/{{Eberron}}''.
** ''TabletopGame/{{Ravenloft}}'' is, itself, a product of Canon Welding, as its PatchworkMap incorporates several domains that were inspired, copied, and/or outright stolen from other AD&D campaign worlds. ''Literally'' stolen, in some cases.
** The "legendary" settings of the various ''AD&D'' Historical Reference books were eventually revealed in the ''[[TimeTravel Chronomancer]]'' appendix to be the past of Gothic Earth from Ravenloft's ''TabletopGame/MasqueOfTheRedDeath'' ...which in turn may be the past of one of the magical ''TabletopGame/D20Modern'' settings -- probably Shadow Chasers (the Red Death gets mentioned in the ''Menace Manual'').
** In D&D 4th Edition, there was a policy to enforce uniformity across the gameline by inserting setting elements from the core material into all official D&D settings, and [[{{Retcon}} retcons]] and setting-shaping disasters were applied wherever necessary to make it so. For example, the cosmology of the ''TabletopGame/ForgottenRealms'' had to allow for such things as the Primordials and the Feywild because those were part of the ''TabletopGame/NentirVale'' cosmology. However ''TabletopGame/DarkSun'' in 4e was largely able to maintain its independence from such core elements, either by slapping new names on old Athasian material (and often ignoring them afterwards) or by rejecting them entirely if they couldn't. (This is in part helped by ''Dark Sun'''s traditional independence from the rest of the D&D line; crossovers were firmly discouraged even at the height of the TSR and Planescape days.)
** The D&D 5th edition supplements ''Plane Shift: Innistrad'' and ''Plane Shift: Zendikar'' enable campaigns to be set in the ''TabletopGame/MagicTheGathering'' multiverse.
* The ''TableTopGame/OldWorldOfDarkness'' started off as a set of {{tabletop RPG}}s each designed as a stand-alone, but since they shared the same basic gameplay and theme, crossovers were an obvious possibility. White Wolf acknowledged this by grouping them together, but they don't all fit that well. ''TabletopGame/VampireTheMasquerade'' has a Biblical origin story, while ''TabletopGame/WerewolfTheApocalypse'' has a pagan backstory. Vampires and mages are both supposed to have secret societies manipulating human history for centuries at least, with directly conflicting goals, yet there's only one case in canon of them fighting each other. And several games have a metaplot pointing to the forthcoming end of the world, but all have a different scenario for it. When it came to mechanics, mages can curbstomp any of the other supernatural beings unless caught unaware (especially vampires, since the best way to counter mages' magic is to ''be alive'').
** The ''TableTopGame/NewWorldOfDarkness'' is made with the possibility of such crossovers explicitly in mind, at the same time keeping each group generally out of each others' way. For example, the Supernal Realms of ''TabletopGame/MageTheAwakening'' and the Shadow World of ''TabletopGame/WerewolfTheForsaken'' have little to do with each other, but equally don't step on each other's cosmological toes.
** ''TabletopGame/{{Exalted}}'' was an inversion. The original concept for the game was for it to be set in the forgotten, mythical prehistory of the ''Old World of Darkness''... but it was ultimately decided not to make this an absolute of the setting, and reduce the connections to common setting elements and parallels that hint at the possibility. The tagline "Before there was a world of darkness..." is TheArtifact of the original concept.
* ''TabletopGame/{{Rifts}}''.
** Want ''Anime/{{Robotech}}'' mecha to fight the ''Franchise/TeenageMutantNinjaTurtles'' alongside unicorn-riding cyborgs, only to have them all ambushed by {{eldritch abomination}}s? Have at it! Creator/PalladiumBooks specifically published conversion books for incorporating their other franchises into ''Rifts'' rules.
** The Rifts Chaos Earth RPG (which takes place ''during'' The Great Cataclysm) explicitly state that ''Rifts'' is the future of the ''TabletopGame/BeyondTheSupernatural'' setting. This had previously been Kevin Siembieda's headcanon, but he hadn't wanted to firmly state it because ''Rifts'' was also supposed to be ''our'' Earth's future.
* The ''TabletopGame/{{Warhammer}}'' and ''TabletopGame/{{Warhammer 40000}}'' universes used to be linked, although the linking statements were made by mad characters. The whole saga/background is told through an UnreliableNarrator anyway. [[WordOfGod Games Workshop]] has stated that the link is now done away with, since it was mostly silly anyway. Warhammer world used to be a planet in the 40k universe, surrounded by warp storms that made it inaccessible for the rest of the galaxy. Nowdays they exist in separate universes, but there appears to be a small link between them in the form of the Warp (the Chaos Gods are the same in each universe, and some people in Warhammer world have gotten visions of Chaos in 40 universe. For example, in ''Liber Chaotica: Book of Khorne'', it's all but outright stated the author is having visions of Abaddon's 13th Black Crusade. Also the [[{{Precursors}} Old Ones]] in ''Warhammer'' appear to be the same as the ones in 40k, and a fan theory suggests they escaped from 40k universe to ''Warhammer'' one after the War in Heaven). There is no real interaction between the two universes, however, unless you count some daemon characters popping up in both universes and a few magic items that have a suspicious resemblance to 40k technology. It also used to be fairly heavily implied that Sigmar (the fantasy Empire's messiah figure and founder) was one of the missing Primarchs (genetically enhanced superhuman offspring of 40k's Emperor). ''TabletopGame/{{Warhammer 40000}}'' was later considered to be simply the SpiritualSuccessor where everything is an {{expy}} of the original ''Warhammer Fantasy''.
* The ''TabletopGame/{{GURPS}}'' TabletopGame/InfiniteWorlds setting ties together every alternate universe they ever came up with and every licensed work ever adapted to ''GURPS'' from ''Literature/{{Uplift}}'' to ''Literature/{{Discworld}}'' to ''ComicBook/{{Hellboy}}''.
* ''TabletopGame/{{Earthdawn}}'' is canonically set in the distant past of the ''TabletopGame/{{Shadowrun}}'' setting.

[[folder:Theme Parks]]
* In ''Ride/JimmyNeutronsNicktoonBlast'', all of the Nicktoons are shown as existing together in a large multiverse, with the soundstages acting as portals between their worlds.
* In Disneyland Paris, ''[[Ride/BigThunderMountainRailroad Big Thunder Mountain]]'' and ''[[Ride/TheHauntedMansion Phantom Manor]]'' have an integrated backstory.

* ''Franchise/{{Transformers}}'':
** Pepsi Convoy is made of sentient metal, the substance that makes up ''VideoGame/{{Pepsiman}}''.
** The "Alternity" toy line links the {{alternate universe}}s of Binaltech, Binaltech Asterisk, and the ''Kiss Players'' radio drama, based on the Japanese ''Franchise/TransformersGeneration1'', and ''Micron Densetsu'', the Japanese version of ''Anime/TransformersArmada'', and the {{Action Figure File Card}}s of the ''Film/{{Transformers}}'' live-action film toy line, and the game ''VideoGame/TransformersConvoyNoNazo''.
** ''Franchise/GIJoe'' is referenced with the ''Transformers: Energon'' Snow Cat (Cyclonus) transforming into a Snow Cat vehicle, the ''Transformers Timelines'' subscription exclusive "Serpent O.R." referencing Serpentor, and the ''Transformers: Generations'' ''Combiner Wars'' Viper turning into a Cobra Rattler plane with a combined Cobra/Decepticon insignia. Exclusive sets from San Diego Comic-Con and the Transformers Collectors' Club combine both series.
* Through commercials, ''Toys/TheTrashPack'', ''Toys/{{Shopkins}}'', and ''Toys/TheGrosseryGang'', all blind-bagged rubber figurines by Moose Toys, share a world.

* Franchise/TheGreenHornet was the son of Franchise/TheLoneRanger's nephew back when the two were on the radio. However due to legal issues between those who currently own the two franchises, the connection isn't used at all anymore.
* When ''Film/TheLastChanceDetectives'' were adapted to radio, their premiere episode included an appearance by Jason Whittaker of ''Radio/AdventuresInOdyssey'', welding the two previously unrelated Focus on the Family franchises.

[[folder:Video Games]]
* ''VideoGame/BioShockInfinite'' combined all of the previous ''VideoGame/BioShock'' games, and perhaps even the ''VideoGame/SystemShock'' titles, into the umbrella of the multiverse. Logistically, this is Ken Levin's way of [[HandWave hand-waving]] his recurring power-ups and obstacles.
-->'''Elizabeth:''' ''(delighted)'' A Sky-Hook!\\
'''Booker:''' A "Sky-Hook"? You mean the Air-Grabber? Kids use 'em to ride up around the pneumo lines.\\
'''Elizabeth:''' Air-Grabber, huh. "Constants and variables"...\\
'''Booker:''' Constants and what?\\
'''Elizabeth:''' Nevermind.
* In ''VideoGame/DragonQuestMonsters'', ''Caravan Hearts'' ties to ''VideoGame/DragonQuestII'' and the original trilogy. ''Terry's Wonderland'' ties into ''VideoGame/DragonQuestVI''.
* ''Franchise/StreetFighter'':
** ''VideoGame/StreetFighterAlpha'' effectively combined the ''Street Fighter'' and ''VideoGame/FinalFight'' franchises into [[SharedUniverse one shared continuity]], by featuring Guy and Sodom from the first ''VideoGame/FinalFight'' as playable characters, followed by Rolento in ''Alpha 2'' and Cody in ''Alpha 3''. ''Final Fight'' was originally intended to be a {{sequel}} to the [[VideoGame/StreetFighterI first]] ''Street Fighter'', and, most importantly, the two franchises had been already officially part of the same continuity since the console version of ''VideoGame/StreetFighterII'' first came out (proof of this was in the [[AllThereInTheManual instruction booklet]]). By extension, this also puts ''Street Fighter'' in the same universe as ''VideoGame/SaturdayNightSlamMasters'', since both that series and ''Final Fight'' feature the character of Mike Haggar. This is confirmed in ''VideoGame/StreetFighterIII'', where Hugo's ending has him about to enter into a tag-team match against two ''Slam Masters'' characters, who will vary depending on who his partner is (for instance, if Elena is chosen, she and Hugo will face off against Haggar and Black Widow). [[AllThereInTheManual Ancillary material]] released for ''VideoGame/StreetFighterV'' also mentions that Rainbow Mika's coach, Yoko, was forced to retire from wrestling after Black Widow injured her during a match. And if that wasn't enough, ''VideoGame/CaptainCommando'' exists TwentyMinutesIntoTheFuture of this SharedUniverse, as one of the playable characters, Sho ([[DubNameChange Ginzu]]), is the successor of the Bushinryu ninjutsu utilized by Guy, a connection that is reiterated when they team up in ''VideoGame/NamcoXCapcom''. The very first level happens to be a future (but still crime-ridden) Metro City, and players can find a bust of Haggar that awards 5000 points at certain points throughout the game.
** A localized example of this comes in the form of the aforementioned Hugo, who was added to the cast of ''VideoGame/StreetFighterIII: 2nd Impact''. His appearance is unmistakably that of Andore from ''Final Fight'', who previously made a cameo appearance in Guy's ''Street Fighter Alpha 2'' stage, and he even has Poison acting as his manager. For some odd reason, [[ContinuityDrift Capcom did not make any mention of the Andore family in Hugo's bio]], instead stating his parents were farmers from Germany and bringing up how Hugo had two younger sisters. It wouldn't be until [[VideoGame/StreetFighterIV several]] [[VideoGame/StreetFighterXTekken years later]] that Capcom would acknowledge Hugo and Andore as one in the same, effectively fusing together his two backstories. A MirrorMatch in ''Street Fighter X Tekken'' will result in the victor mistaking the loser for Andore Jr. while his intro sequence in ''Ultra Street Fighter IV'' features Hugo reminiscing about his mother and his life back home in Germany.
** With Zeku's playable appearance in Season 2 of ''Street Fighter V'' comes heavy implications that he goes on to found [[VideoGame/{{Strider}} the Striders]], thus making the ''Strider'' series also part of the ''SF'' canon.
* ''VideoGame/MegaManLegends'' was originally in its own continuity (hence jokes and references to the original series being a ShowWithinAShow). However, ''VideoGame/MegaManZero'' and ''VideoGame/MegaManZX'' [[VideoGame games]] have more directly connected it as being the far distant future of the original ''VideoGame/{{Mega Man|Classic}}'' and ''VideoGame/MegaManX''.
* When Creator/{{SNK}} made ''Art of Fighting 2'', they decided to officially make the ''VideoGame/ArtOfFighting'' series part of the same continuity as the ''VideoGame/FatalFury'' series. To explain why the ''Art of Fighting'' cast were not around during the events of the ''Fatal Fury'' games, they made the ''Art of Fighting'' series a {{prequel}} to the ''Fatal Fury'' series by setting it ten years before and putting a young Geese Howard as the TrueFinalBoss in ''Art of Fighting 2'' (back when he was still the police commissioner of South Town). When SNK later wanted to cross the ''Fatal Fury'' cast with the ''Art of Fighting'' cast in ''VideoGame/TheKingOfFighters'' games, they had to place the third series [[AlternateContinuity in a separate continuity]]. And from there, it starts getting ''really'' weird, with Ralf and Clark from ''VideoGame/IkariWarriors'' and Athena from ''VideoGame/PsychoSoldier'' (who is the descendant/ambiguously-the-reincarnation of the Athena from ''VideoGame/{{Athena}}'') appearing in ''VideoGame/TheKingOfFighters'' -- despite ''Psycho Soldier'' involving an invasion of monsters from beneath the earth that you'd kind of think would get mentioned at some point in ''KOF'' canonicity if it happened -- and then both Ralf and Clark and ''KOF'' original Leona appearing in ''VideoGame/MetalSlug 6'' and ''Metal Slug 7''. At this point, the only sane response to the SNK canon is to throw up your hands and shout "I don't know!" Other SNK titles, from ''VideoGame/SamuraiShodown'' to ''VideoGame/TheLastBlade'' to ''[[VideoGame/FuunSeries Savage Reign/Kizuna Encounter]]'', have been alluded to in varying extents throughout ''KOF''[='s=] run.
** ''The King of Fighters XIV'' goes a step further by introducing the Another World Team, consisting of Nakoruru (of ''Samurai Shodown'' fame, last seen as a non-canon fighter in the UsefulNotes/GameBoy port of ''[='95=]''), Mui Mui (from the pachinko game ''Dragon Gal''), and Love Heart (from the pachinko game ''Sky Love''), who are drawn into the ''KOF'' world due to a dimensional rift. In short, the implication is that any of the SNK games that don't fit neatly into the ''KOF'' timeline, and even some of the ones that could, all exist as part of [[TheMultiverse a greater cosmology]].
* The ''Franchise/FinalFantasy'' series is mostly a NonLinearSequel, but has a few counts of direct crossover. Some early examples are [[VideoGame/FinalFantasyV Gilgamesh]], who was banished to a world between universes and is the same person in most of his appearances. [[VideoGame/FinalFantasyVII Cloud]] later appeared as a guest character in ''VideoGame/FinalFantasyTactics'', via a machine that can reach across time and space. (The remastered version of ''Tactics'' for the PSP also adds [[VideoGame/FinalFantasyXII Balthier]] and [[VideoGame/FinalFantasyTacticsA2 Luso]].) Around the time ''VideoGame/DissidiaFinalFantasy'' appeared, games (especially mobile spinoffs) began suggesting that all the worlds of ''Final Fantasy'' are planets in numerous universes separated by the Void, which can be crossed on occasion.
** The ''Franchise/IvaliceAlliance'' series was the first attempt to make a ''Final Fantasy'' universe that included more than one game and in fact includes games without the ''Final Fantasy'' name. ''Final Fantasy Tactics'', the ''VideoGame/FinalFantasyXII'' titles, ''VideoGame/VagrantStory'', ''Crystal Defenders'', and the [[{{Vaporware}} not yet released]] ''Fortress'' are among the confirmed games to take place in the Ivalice universe. WordOfGod is that ''Vagrant Story'' wasn't ''supposed'' to be part of the setting, but GodDoesNotOwnThisWorld, and the people who do decided to shove it in there based on what were intended to be a few referential in-jokes.
** Hints have been dropped [[VideoGame/FinalFantasyX2 here and there]] (and WordOfGod has outright stated) that ''VideoGame/FinalFantasyVII'' takes place in the far future of the ''VideoGame/FinalFantasyX'' world, on a different planet.
** And then ''VideoGame/DissidiaFinalFantasy'' made it so they're all parallel worlds in a shared multiverse, although its canonicity is uncertain. Would make sense, though. It is a series.
** ''VideoGame/FinalFantasyIVTheAfterYears'' reveals that every crystal-based ''Final Fantasy'' game is in the same universe. [[spoiler:The crystals are placed on a planet with promise, both to guide and record the evolution of the planets; hence why they all have humans, and not-entirely-different environments from the other ''Final Fantasies''. To prove it, the party fights such recorded monsters as [[VideoGame/FinalFantasyI The Four Fiends]], [[VideoGame/FinalFantasyIII the Dark World Crystal Guardians]], [[VideoGame/FinalFantasyV Gilgamesh, and the superbosses Omega, Shinryu]], [[VideoGame/FinalFantasyVI Death Gaze and Ultima Weapon]].]]
** ''VideoGame/FinalFantasyRecordKeeper'' presents the ''Final Fantasy'' game worlds as Record Realms accessible through paintings of events from those games.
** ''VideoGame/FinalFantasyBraveExvius'' features characters from different games, brought to the world as Visions, retaining aspects and memories of their lives before they inevitably died.
** ''VideoGame/MobiusFinalFantasy'' appears to be a prequel to ''VideoGame/FinalFantasyI'', set on a planet called Palamecia (the same name as the Empire from ''VideoGame/FinalFantasyII''), which is apparently a sort of cosmic training ground for creating crystal heroes. The main character, Wol, doesn't come from the world itself, but whatever world it was he came from also had Chocobos and the Gilgamesh from ''VideoGame/FinalFantasyV''. This is already fairly mindbending without mentioning [[VideoGame/FinalFantasyVII Cloud's]] cameo or the time when [[VideoGame/FinalFantasyVIII PuPus invaded]], so nothing more will be said about that.
** Without saying much about it, ''VideoGame/{{Lightning Returns|FinalFantasyXIII}}'' adds a connection between the ''Final Fantasy'' worlds and [[LikeRealityUnlessNoted our planet]]. [[FridgeLogic This arguably welds the series to]] ''VideoGame/ParasiteEve''.
** Somewhat averted in ''VideoGame/FinalFantasyXV'', which featured a version of Gilgamesh that is a different character to the usual one, and had most of its indications that it happened in the ''VideoGame/FinalFantasyXIII'' universe removed in development.
** ''VideoGame/DissidiaFinalFantasyOperaOmnia'' goes for a MassiveMultiplayerCrossover as characters are retrieved from various points in their stories to interact in a single world.
* When Bohemia Interactive, the Czech developer of ''VideoGame/OperationFlashpoint: Cold War Crisis'' (their first game), split with the publisher Creator/{{Codemasters}}, they were able to keep the "''assets''"[[note]]above all the game engine[[/note]] but not the game's brand name, so they ended up creating a SpiritualSuccessor called ''VideoGame/{{ARMA}}''. However, BI has since come out and said that both series are in a SharedUniverse, as was BI's spin-off ''Videogame/TakeOnHelicopters'', and indeed [[spoiler:the British player character of both ''ARMA 2: Operation Arrowhead'' is a minor antagonist NPC in ''Take On Helicopters'']]. The final patch ([=v1.99=]) for ''Operation Flashpoint'' even renames it to ''ARMA: Cold War Assault''. Talk about paying attention to details.
* ''VideoGame/SuperSmashBros'':
** The fourth game seems to pick up where both ''VideoGame/TheSubspaceEmissary'' (''Brawl''[='=]s Story Mode) and ''VideoGame/KidIcarusUprising'' left off, as the various Palutena's Guidance conversations make reference to both games. [[spoiler:Dark Pit's conversation in particular shows that, following the events of ''Uprising'', he's decided to side with Viridi for reasons unknown.]]
** The Smashverse versions of Marth, Ike, Lucina and Robin are summonable in ''VideoGame/FireEmblemFates'', fittingly, via their Toys/{{amiibo}} (their real-life trophies). When talked to, they reflect on their experiences in the ''Smash'' universe, but Robin and Lucina also recognize characters from their [[VideoGame/FireEmblemAwakening game of origin]] that never appeared in ''Smash'', which leads to confusion between the characters due to the whole AlternateUniverse thing.
* The [[MegaCorp Ultor Corporation]], from ''VideoGame/RedFaction'', a science-fiction series about Martian rebels, makes an appearance in ''VideoGame/SaintsRow'', a series about gang warfare in a contemporary American city. ''VideoGame/RedFaction: Guerilla'' references this with "Mount Vogel", named after the CEO of Ultor in ''VideoGame/SaintsRow2''. This started off as a ShoutOut in the original ''VideoGame/SaintsRow'', with a few references to Ultor here and there. Then ''VideoGame/SaintsRow2'' ran with it, and made Ultor a major faction that is clearly the same one as in ''VideoGame/RedFaction''. However, ''VideoGame/SaintsRowIV'' separates the canon, to say the least. ''Maybe.'' [[spoiler:The ending implies a certain amount of time-travel, so who can say?]]
* The sheer amount of shout-outs to ''[[VideoGame/NightsIntoDreams NiGHTS]]'' in the ''Franchise/SonicTheHedgehog'' series has led some people (including those of semi-official status) to claim they are in the same universe.
* ''VideoGame/ElementalWarOfMagic'' shares a ''lot'' of its terminology (especially in its backstory) with ''VideoGame/GalacticCivilizations'', indicating that the game may be set on ancient Altaria and the channellers are SufficientlyAdvancedAliens.
* ''VideoGame/BetrayalAtKrondor'' and ''[[Literature/TheRiftwarCycle Riftwar]]'', mentioned under Cross-Media.
* {{Easter egg}}s in {{Creator/Sierra}}'s adventure games point to a [[http://kingsquest.wikia.com/wiki/Multiverse shared continuity]]:
** In ''VideoGame/LeisureSuitLarry'', Rosella appears as a hairdresser in the second game and an actress re-enacting her game in the third game.
** In ''VideoGame/PoliceQuest'', it is possible to stop at the disco from ''VideoGame/LeisureSuitLarry'', find a character from ''Leisure Suit Larry'' in jail, find Larry at the airport, and read news in the Lytton Tribune about dragons and gnomes in Daventry.
** In ''[[VideoGame/QuestForGloryI Quest for Glory]]'', The Adventurer's Guild Hall has a mounted Antwerp head: "The plaque reads: 'Antwerp slain by [[VideoGame/SpaceQuest two guys from Andromeda]]'". In the SCI version, Erasmus' house has an artifact called "[[VideoGame/KingsQuestIVThePerilsOfRosella The Rosella Stone]]".
** In ''VideoGame/QuestForGloryIV'', the mad scientist Dr. Cranium is the great-great grandson of [[VideoGame/DrBrain Dr. Thaddeus Egghead Brain]] from ''The Castle of Dr. Brain'' and ''The Island of Dr. Brain''.
** In ''[[VideoGame/SpaceQuestITheSarienEncounter Space Quest]]'' (EGA), pushing the Arcada escape pod's "Don't Touch" button sends the escape pod to The Daventry Zone, landing in Daventry Castle's moat, where Ken and Roberta Williams are having a conversation, mentioned by King Graham, Princess Rosella and Roger Wilco in ''Hoyle Book of Card Games, Volume I''. In the VGA remake, the escape pod lands in ''Conquests of the Longbow'''s Nottingham Castle. In the VGA version, the Federation president strongly resembles King Graham.
** In ''[[VideoGame/SpaceQuestIVRogerWilcoAndTheTimeRippers Space Quest IV]]'', the helpless stranger, identified as Maharg in the game's files, is carried away by a Pterodactyl, much like the Roc carries away King Graham in ''[[VideoGame/KingsQuestVAbsenceMakesTheHeartGoYonder King's Quest V]]''. In the Galaxy Galleria, plants come from [[VideoGame/QuestForGloryII Shapeir]] florists.
** In the ''[[VideoGame/SpaceQuestVTheNextMutation Space Quest V]]'' copy protection, the ''Galactic Inquirer'' article "Gir Draxon's predictions for 3010" features Gir Draxon. Gir Draxon is the [[{{EvilOverlord}} Supreme Overlord]] of the Arcturus system and BigBad of Dynamix's ''Stellar 7'', ''Nova 9'' and ''Stellar-Fire'' [[http://www.hardcoregaming101.net/stellar7/stellar7.htm series]] of futuristic tank games, though Gir Draxon is not in ''Stellar 7'''s spiritual sequel ''Arctic Fox''. The [=StarCon Academy=] orbits planet Nova 9. In ''Nova 9'', Nova 9 is the name of a star system.
** In ''[[VideoGame/SpaceQuestVIRogerWilcoInTheSpinalFrontier Space Quest VI]]'', prisoners are sent to labor camps on the planet Daventry VIII.
** The Hoyle games featured King Graham, Rosella, Roger Wilco, Sonny Bonds, Larry Laffer, and Sierra staff and relatives.
** The extra-canonical hintbooks ''The King's Quest Companion'', ''Leisure Suit Larry's Bedside Companion'' and ''The Space Quest Companion'' give the characters a DirectLineToTheAuthor.
* Creator/BandaiNamcoEntertainment seems to have merged parts of the previously unrelated (despite numerous [[ShoutOut Shout-Outs]]) ''VideoGame/{{Galaxian}}''[=/=]''VideoGame/{{Galaga}}'' series, ''VideoGame/AceCombat'' series, ''VideoGame/RidgeRacer'' series, and some other games into an overarching ''[[http://acecombat.wikia.com/wiki/United_Galaxy_Space_Force United Galaxy Space Force]]'' series.
* In the PC game series ''VideoGame/DarkParables'', [[AllMythsAreTrue all fairy tales are true]], and they're all pretty much part of one gigantic story. Literature/SleepingBeauty is sister-in-law to Literature/TheFrogPrince while [[Literature/TheSnowQueen Gerda]] is descended from [[Literature/HanselAndGretel Hansel]], for starters. Sometimes characters from two (or more) different fairy tales will even turn out to be the same person; for example, [[spoiler:Snow White is also the Snow Queen]].
* ''VideoGame/CommanderKeen'' and ''VideoGame/Wolfenstein3D'' are linked together by way of ''Commander Keen''[='s=] Billy Blaze being the grandson of ''Wolfenstein''[='s=] B.J. Blazkowicz. A common fan theory is that the protagonist of ''VideoGame/{{Doom}}'' is also part of the family. The RPG versions of their respective games go with this -- the "Harbinger of Doom" from ''Wolfenstein RPG'' is basically ''Doom''[='s=] Cyberdemon without prosthetics, and the hero of ''Doom RPG'' is explicitly given the last name "Blazkowicz." Also, ''Doom II''[='s=] Commander Keen and ''Wolfenstein 3D''[='s=] EasterEgg BonusLevel, though no in-story reason is given for their existence.
* Ever since 2004, ''VideoGame/NinjaGaiden'' has been established to be in canonicity with ''VideoGame/DeadOrAlive'' series with Ryu being the canonical winner of the second tournament and ''Dead or Alive'' character [[ActionGirl Ayane]] acting as a support character throughout many ''Ninja Gaiden'' installments. [[TheHero Kasumi]] herself would later appear in the newer ''Ninja Gaiden'' games, first making two cameo appearances in ''Ninja Gaiden Sigma 2'' before [[PromotedToPlayable being bumped up to playable status]] in ''Ninja Gaiden 3: Razor's Edge''. In turn, Rachel and Momiji (respectively from the 2004 ''Ninja Gaiden'' and ''Ninja Gaiden: Dragon Sword'') would [[CanonImmigrant cross over to]] ''DOA'' with ''VideoGame/DeadOrAlive5 [[UpdatedRerelease Ultimate]]''. Additionally, ''Dead or Alive: Dimensions'' reveals that [[spoiler:Sonia, one of Ryu's allies in ''Ninja Gaiden II'', is merely an alias for Irene Lew, his love interest in the original NES trilogy (and wife by the time of the first ''DOA''); Irene shows up in person during ''Razor's Edge'' and serves as Ayane's MissionControl after only being indirectly mentioned by Ryu in the original game]].
* Up until ''VideoGame/FireEmblemAwakening'', it was assumed that, barring remakes and direct sequels/prequels (and ''[[VideoGame/FireEmblemGaiden Gaiden]]'' which was a GaidenGame to ''[[VideoGame/FireEmblemShadowDragonAndTheBladeOfLight Shadow Dragon]]'' featuring a small number of its characters), all ''VideoGame/FireEmblem'' games were set in different universes and did not impact each other. [[note]]WordOfGod prior to ''Awakening'' did state that Jugdral, the setting of ''[[VideoGame/FireEmblemGenealogyOfTheHolyWar Genealogy of the Holy War]]'' and ''[[VideoGame/FireEmblemThracia776 Thracia 776]]'', existed in the same world as Archanea and Valentia, confirming Naga to be the same character between all her appearances (or at least various incarnations of the same character).[[/note]] However, [=SpotPass=] and DLC content for ''Awakening'' used characters from previous ''Fire Emblem'' games--including ones that were not set in the [[VideoGame/FireEmblemAkaneia Archanea universe]]--and so to get around this, introduced a "gateway" (the Outrealm Gate) that allowed characters to travel between the different universes. This would imply that all of the worlds are connected, physically or otherwise, as part of some greater universe rather than separate, alternate worlds. As detailed above, ''VideoGame/FireEmblemFates'' even adds the ''VideoGame/SuperSmashBros'' universe to the mix.
** Outside of a multidimensional context, the universe of [[VideoGame/FireEmblemAkaneia Archanea]], [[VideoGame/FireEmblemGaiden Valentia]], and [[VideoGame/FireEmblemJugdral Jugdral]] was merged with that of [[VideoGame/FireEmblemTellius Tellius]].
** A localized example comes from ''Echoes: Shadows of Valentia'', the 2017 remake of ''Gaiden''. While ''Gaiden'' was indeed a side-story to the titles set in Archanea, there were very few tangible links between games beyond the appearances of the Whitewing sisters and [[spoiler:Zeke, an amnesiac Camus from ''Shadow Dragon'']], with one of these -- [[spoiler:Alm inexplicably finding the Falchion in Duma Temple]] -- leaving players scratching their heads in confusion for many years. The remake, on the other hand, more neatly ties together ''Gaiden'' with the Archanean games as part of [[AdaptationExpansion its expanded retelling]]. Aside of definitively stating [[spoiler:Camus decides to stay in Valentia with his lover Tatiana following [[VideoGame/FireEmblemMysteryOfTheEmblem his stint as Sirius]] provided both of them survive to the end]], ''[=SoV=]'' establishes [[spoiler:Mila and Duma as members of the Divine Dragon Tribe who were exiled thousands of years beforehand]], with [[spoiler:Naga forging a second Falchion from one of her fangs and giving it to Duma as a countermeasure should they succumb to degeneration, much like many of the other dragons would in the backstory of Marth's games]]. In fact, [[spoiler:Mila describes the Valentian Falchion as the "one and only godslaying sword," implying it was crafted far earlier than its Archanean counterpart]]. Furthermore, the postgame involves traveling across the sea to the western outskirts of Archanea, where the player investigates the ruins of Thabes, an ancient civilization in the Mamorthod Desert mentioned in ''Mystery of the Emblem''. This dungeon, Thabes Labyrinth, manages to [[BelatedBackstory provide some much-needed backstory]] for none other than [[spoiler:Grima, the BigBad of ''Awakening'', revealing he and the Death Masks, the original Risen, were the products of forbidden experiments conducted by a mad alchemist named Forneus, forcing the Thabean council to seal him and his creations away within his workshop]].
* Fitting its business model of only developing games that can be turned into franchises, Creator/{{Ubisoft}} seems well into doing this by starting to connect its existing franchises of ''Franchise/AssassinsCreed'', ''VideoGame/WatchDogs'' and ''VideoGame/FarCry''.
* ''VideoGame/LandsOfLore'' and ''VideoGame/TheLegendOfKyrandia'' share a continuity. Both mention the Kyragem, [[RedHerring Piscata Rosea]], Pseudobushia Hugiflora, and Scotia.
* Discussed in ''VideoGame/ProjectXZone'' where (on top of canonizing about a dozen other crossover games; see the Cross-Media section above) the characters from the many different universes have some fun trying to link them together. For instance, the characters of ''VideoGame/GodsEaterBurst'' find it plausible that their world would continue on a downward spiral, necessitating the construction of [[VideoGame/ResonanceOfFate Basel]] in their far future. However, it's also acknowledged that certain universes are mutually exclusive with each other (''VideoGame/SakuraWars'' is technologically and geopolitically incompatible with modern Earth) or completely isolated (''VideoGame/TalesOfVesperia'' is shown to be in its own disconnected bubble), so nothing is set in stone.
* ''VideoGame/QuakeIIIArena'' mashes ''VideoGame/{{Doom}}, VideoGame/{{Quake}}'', and ''VideoGame/QuakeII'' into a single continuity. ''VideoGame/QuakeChampions'' mashes all of this with Id's remaining franchise, ''VideoGame/{{Wolfenstein}}'', and possibly with ''VideoGame/{{Heretic}}'' and its sequels, if Galena is any indication.
* ''Season of the Sakura'' and ''Runaway City'' both feature Rin Watanabe and the ''Virtual Ninja'' arcade game series, and share similar backgrounds and character designs, along with ''Three Sisters' Story''.
* The [=PS2=]-era ''VideoGame/GrandTheftAuto'' games are in the same continuity as the ''VideoGame/{{Manhunt}}'' series -- Carcer City is explicitly stated to be a location in the Grand Theft Autoverse, and it was introduced even before Manhunt was released. And the ''VideoGame/GrandTheftAutoIV'' universe (which it shares with ''VideoGame/GrandTheftAutoV'') may be shared with ''VideoGame/{{Bully}}'', with the appearance of the Bullworth Academy on TV.
* [[VideoGame/CapcomVsWhatever Some of Capcom's more robust crossovers]], like ''VideoGame/TatsunokoVsCapcom'' and ''VideoGame/MarvelVsCapcom3'', imply that many a Capcom franchise share some implicit but mostly unexplored degree of connectivity (going beyond the SharedUniverse the ''Franchise/StreetFighter'' franchise is known to be part of). For example, [[VideoGame/{{Darkstalkers}} Morrigan]] in ''[=TvC=]'' expresses disappointment that VideoGame/ViewtifulJoe didn't live up to what she learned from Joe's rival Alastor. Alastor, as per the [=PS2=] version of ''Viewtiful Joe'', is the spirit of the sword Dante picks up in the original ''Franchise/DevilMayCry'' and Dante's (admittedly non-canonical) story in ''Viewtiful Joe'' [[spoiler:has Mundus, the BigBad of ''[=DMC1=]'', as TheManBehindTheMan]]. Likewise, Dante and Joe are shown to be buddies/friendly rivals given their ''[=MvC3=]'' intro quotes for each other, which would be strange (seeing as they never actually met in ''Viewtiful Joe'') if not for the fact that Dante was a playable character in the PSP port of ''Viewtiful Joe: Red Hot Rumble''.
** If that wasn't enough, there are multiple hints throughout ''VideoGame/{{Bayonetta}}'' pointing to the fact that [[IntercontinuityCrossover it exists in the same world as]] ''Devil May Cry''. Given that ''DMC'' and ''Bayonetta'' were [[Creator/HidekiKamiya created by the same guy]] (who was also responsible for the first ''Viewtiful Joe''), this is not entirely surprising.
** Speaking of ''Viewtiful Joe'', WordOfGod states [[VideoGame/ViewtifulJoe Sexy Silvia]] and [[VideoGame/TheWonderful101 Wonder-Cheerleader]] (an {{Expy}} of the former) [[CanonImmigrant are actually the same person]], which would make her full name Silvianne "Silvia" Lumiere. Joe is even directly mentioned during one of Wonder-Pink's failed QTE sequences, alluding to the third ''Viewtiful Joe'' game that was never made.
* Way back in the Amiga days, ''Super VideoGame/{{Turrican}}'' took place on the planet of [[https://en.wikipedia.org/wiki/Katakis Katakis.]] This was referenced in the Turrican clone ''Hurrican'', which took place on the planet Takatis (which was the name of a clone of ''Katakis'' by the same team, [=Poke53280=]).
* In the ''VideoGame/{{Ultima}}'' series, Britannia has featured a few heroes from other worlds, including Seggallion, the hero of Origin's ''Knights of Legend'', set in the world of Ashtalarea, Gorn, the hero of Origin's ''The Quest'' and ''Ring Quest'', set in the world of Balema, and the fighter Gertan, hero of the UsefulNotes/AppleII game ''The Caverns of Freitag''. The Kilrathi ship in ''VideoGame/UltimaVII'' and the Trilkhai in ''[[VideoGame/UltimaUnderworld Ultima Underworld II]]'' link ''VideoGame/{{Ultima}}'' to ''VideoGame/WingCommander''. ''[[VideoGame/UltimaVIIPartII Serpent Isle]]'' would have featured a stranded Kilrathi pilot on the isle of Claw. ''Ultima Forever'' would have featured an island with a Kilrathi monument and an island with a crashed Dralthi ship.
* Again, par for the course regarding ''VideoGame/SuperRobotWars'', due to their MegaCrossover nature, but the specific example goes to ''VideoGame/SuperRobotWarsOriginalGeneration'', having the unenviable task of integrating the countless OriginalGeneration stories from previous ''Super Robot Wars'' installments into a cohesive UltimateUniverse, often filling in the blanks left by licensed characters with its OriginalGeneration. For example, the "[[AMechByAnyOtherName Choukijin]]" from ''VideoGame/SuperRobotWarsAlpha'' were originally connected to the ''Anime/MazingerZ'' mythos; in ''Original Generation'', they were created to combat the [[EldritchAbomination Einsts]] from ''VideoGame/SuperRobotWarsCompact2''. A later ''Original Generation'' installment, including at least [[VideoGame/SuperRobotWarsZ one licensed saga]], places more emphasis on space-time dimensional elements, a handy way of working in anything that can't be shoehorned in thoroughly into main continuity, but also working around obstacles that might violate pre-established canonicity. From there, the ''VideoGame/EndlessFrontier'' games tie it to ''VideoGame/NamcoXCapcom'' and the ''VideoGame/{{Xenosaga}}'' series, then they all ended up in ''VideoGame/ProjectXZone''.
* Several Sony Online Entertainment employees have [[http://www.reddit.com/r/Planetside/comments/2p3706/nanite_systems_in_h1z1/ joked]] that their zombie apocalypse sandbox game ''[=H1Z1=]'' and their MMOFPS ''VideoGame/{{Planetside}} 2'' exist in the same universe, where ''Planetside'' is a LostColony of escapees from ''[=H1Z1=]''. The Nanite Systems MegaCorp that makes vehicles and weapons in ''Planetside'' appear in ''[=H1Z1=]'', apparently as a pharmaceutical company. The New Conglomerate MegaCorp likewise appears in ''[=H1Z1=]'' as a manufacturer of bluejeans. However, in practice it is just a ProductionThrowback.
* Deconstructed while being PlayedForDrama in the Story Mode of ''VideoGame/MortalKombatVsDCUniverse''. As a result of [[Franchise/MortalKombat Shao Kahn]] and [[Franchise/TheDCU Darkseid]] merging (by accident, [[WhatTheHellHero after being beaten by Raiden and Superman in their respective Universes]]) to become the entity known as ''[[BigBad Dark Kahn]]'', their mere existence is causing both ''Mortal Kombat''[='s=] universe and [=DC=]'s universe to become one. At first this is seen as heroes and villains crossing over to the other's universes to fight one another, until both factions travel to Outworld/Apokolips, where they see the damage that is being done to their universes by Dark Kahn [[LetsYouAndHimFight after he had manipulated them all into fighting one another to make him stronger]]. By the end however, Raiden and Superman team up to take out Dark Kahn and their universes separate.
* In the ''VideoGame/WingCommander'' series, ''Wing Commander Secret Ops'' and the ''Wing Commander: Arena'' manual mentions the WEC, the [[OneNationUnderCopyright Corporatocracy]] of the ''VideoGame/{{Crusader}}'' series.
* Ubisoft's ''Franchise/AssassinsCreed'' and ''VideoGame/WatchDogs'' take place in the same universe. This was first shown in ''VideoGame/AssassinsCreedIVBlackFlag'' having an in-game email from Blume, a security firm from ''Watch_Dogs'', proposing Abstergo Industries make use of their ctOS system. Furthermore, the COO of Abstergo Entertainment from the same game is said to gone missing suddenly after a business meeting in Chicago, the setting of the first ''Watch_Dogs''. In that game it turns out the Assassins hired Aiden Pierce to take care of the COO for them. While some players of both games originally assumed these to be nothing more than easter eggs, ''VideoGame/AssassinsCreedOrigins'' makes the connection of their universes 100% certain by confirming that yes the mission where Aiden kills the COO of Abstergo Entertainment is part of the official ''Assassin's Creed'' canon.
* The United Galaxy Space Force (UGSF) Series created by Namco in 2011 unified numerous titles into a single universe, including ''VideoGame/{{Galaxian}}'', ''VideoGame/{{Galaga}}'', ''VideoGame/{{Bosconian}}'', ''VideoGame/DigDug'', ''VideoGame/{{Starblade}}'' and ''VideoGame/MizuiroBlood''. ''VideoGame/AceCombat3Electrosphere'' serves as its starting point.
* If the quote is any indication, VideoGame/CommandAndConquerRedAlert was about to be welded with VideoGame/CommandAndConquerTiberianSeries before going off the rails and becoming its own universe.
-->'''Nadia:''' This temporary chaos in Europe would only serve to fuel ''[[AncientConspiracy The Brotherhood's]]'' cause...
-->'''The Advisor[[spoiler:/Kane]]:''' ...The temporary future? Comrade chairman, ''I am the future!''

[[folder:Web Comics]]
* The ''Webcomic/MSPaintAdventures'' series ''Webcomic/ProblemSleuth'' was tied into the earlier ''Webcomic/{{Jailbreak}}'' series when Zombie Ace Dick and his whale crashed into the jail where ''Jailbreak'' was set. Indeed, a dead whale was part of an early ''Jailbreak'' puzzle, and ZAD and the Completely Sane Man were revealed to be the skeletons in one of the cells.
* ''Webcomic/{{Homestuck}}'''s [[ShowWithinAShow Comic Within A Comic]] ''Webcomic/SweetBroAndHellaJeff'' predates ''Homestuck''. It was originally written as a parody of another {{webcomic}} called ''[[http://forums.penny-arcade.com/showthread.php?t=85435&page=3 Higher Technology]]'', and was written into ''Homestuck'' as a {{webcomic}} run by Dave Strider.
** In a semi-canonical donation extra the ''Webcomic/ProblemSleuth'' characters did battle with the Midnight Crew. That gang would later become extremely plot important in ''Webcomic/{{Homestuck}}''. Even though both Problem Sleuth ''and'' the Midnight Crew exist as fictional works in the ''Homestuck'' universe -- in fact, instead of ''Homestuck'', in-universe the [[Webcomic/MsPaintAdventures adventure]] following Problem Sleuth was based on The Midnight Crew. To confuse the issue further, an Easter Egg in ''Homestuck'' implies that Problem Sleuth took place on Prospit, making Problem Sleuth canonical to the ''Homestuck'' multiverse.
* In ''Webcomic/StarslipCrisis'', the character of Vore is all but explicitly stated to be in fact Vaporware from the author's previous comic, ''Webcomic/CheckerboardNightmare''. However, this can be considered only to be a partial example, since said strip's events are never mentioned in ''[[Webcomic/StarslipCrisis Starslip]]'' and Vore himself seems to have lost his memory up to that point, causing a bit of a personality change (yes, Vaporware also expressed desires to exterminate mankind, but Vore's a lot more proactive about it), so for all intents and purposes Vore can be considered a separate character. Eventually he did regain his old memories and personality, and started calling himself Vaporware again...[[spoiler:right before he was killed off for real]]. But records of the past (or Real Life, 21st Century Earth) seem to be extremely sketchy, as evidenced by the ShowWithinAShow "Concrete Universe," where covered wagons exist at the same time as cloning.
* ''Webcomic/CrossoverWars'' and ''Webcomic/TheCrossoverlord'' established many {{webcomic}}s as part of the same {{multiverse}} with rules more akin to Westphall's mind. The [[https://web.archive.org/web/20150423152459/http://www.webcomicsnation.com/crossoverlord/REALITEASE.php Realitease]] [[AllThereInTheManual page]] done by ''[[Webcomic/TheCrossoverlord Crossoverlord]]'' creators contains interesting informations about which {{webcomic}}s happens in the same universe with lists of proofs and explanations:
** ''WebComic/{{Fans}}'' and ''Webcomic/CollegeRoomiesFromHell'' seems to be set not only in the same universe but also share it with ''eight'' other {{webcomic}}s.
** ''Webcomic/SomethingPositive'' shares a world with ''Webcomic/QueenOfWands'', ''Webcomic/PunchAnPie'', ''Scandal Sheet'', ''Webcomic/GirlsWithSlingshots'', ''Webcomic/QuestionableContent'', ''Webcomic/{{Shortpacked}}'', ''Webcomic/PennyAndAggie'' and ''All New Issues''. For example, the cats from [=S*P=] and GWS had a litter of hypoallergenic kittens.
** ''Webcomic/MegaTokyo'', ''Webcomic/AppleGeeks'', ''Webcomic/CtrlAltDel'', ''Webcomic/QuestionableContent'', ''Webcomic/{{Shortpacked}}'' and ''Webcomic/DieselSweeties'' are all set in one universe. Also, one of the hypoallergenic kittens of [[Webcomic/SomethingPositive Choo-Choo Bear]] and [[Webcomic/GirlsWithSlingshots Sprinkles]] ("the fat one") was given to [[Webcomic/{{Walkyverse}} Leslie Bean]] by her lesbian lover's sister, Roz in a weird, drug deal-like handoff with [[Webcomic/SomethingPositive Davan]]. In the words of [[Webcomic/{{Walkyverse}} David Willis]], "{{Webcomics}} are so incestuous".
** ''Webcomic/{{Mindmistress}}'' shares a universe with ''Webcomic/ClanOfTheCats'' and ''LCD'', as well as with ''Webcomic/ZebraGirl'' or her alternate counterpart.
** ''Webcomic/{{Crossoverkill}}'' fueled the fire, not only adding more webcomics to TheMultiverse, but also with revelation that Doppleganger Gang members are all alternate reality counterparts of one another and there are members from viarous webcomics among them, including several fantasy webcomics.
* ''Webcomic/HeroesUnite'' did it with a horrifying amount of SuperHero {{webcomic}}s, hosted on Website/DrunkDuck. First it established that ''Webcomic/{{Energize}}'', ''Bombshell,'' and an alternate counterpart of ''Webcomic/{{Acrobat}}'' share an universe, and then a bunch of other superheroes joined in. Some writers even took an advantage of it to make their webcomics more popular. The creators of ''Webcomic/{{Energize}}'' and ''Webcomic/{{Dasien}}'' did a short (currently on hiatus) crossover between their characters, while the former used a new SharedUniverse to bring back his other {{webcomic}}s - ''Fearless'', Webcomic/{{SHELL}} teamed up with The Blonde Marvel and Bombshell and gets his ass kicked by one of Webcomic/HeroForce members before joining HU, and Vora, Princess Of The Skies, appeared a few times in HU before getting her own adventures. And it's all one reality in the {{webcomic}}s {{multiverse}}. Having kickstarted the whole superhero crossover thing on Website/DrunkDuck, ''Webcomic/HeroesUnite'' is now set in its own self-contained universe, but the crossover goodness continues in the spinoff ''Heroes Alliance'' with the characters from ''Webcomic/KarabearComicsUnlimited'' and even involved WebOriginal/JennyEverywhere and golden age characters like Madame Fatal.
* Creator/TCampbell has done this with various webcomics he's written or co-authored, both played straight and using alternate versions of characters.
** ''Webcomic/PennyAndAggie'', ''Webcomic/CoolCatStudio'' and ''Sketchies'' are set in the same universe. However, the SF and supernatural elements in ''Webcomic/CoolCatStudio'' are absent from the other two comics. Campbell once [[WordOfGod explained]] this on the ''P&A'' forum by stating that such elements exist on the periphery of the comics' shared universe, so not all its inhabitants experience, nor are even aware of, such things.
** This is in contrast to the ''Webcomic/{{Fans}}'' universe (and its alternate versions of ''P&A'''s characters), where, particularly after the {{Revival}}, paranormal occurrences are so frequent and prominent that the entire world is aware of them. Also, alternate versions of characters from ''Webcomic/PennyAndAggie'' and ''Webcomic/{{Fans}}'' appear in each other's universes every so often.
* Barry T. Smith's ''Webcomic/InkTank'' appeared to be in an entirely new universe from the previous strips...until a story arc which ended with the AuthorAvatar having a nervous breakdown was resolved by Dante from ''Angst Technology'' turning up and treating him to a coffee.
* Artist Ursula Vernon's ''Webcomic/{{Digger}}'', an anthro adventure about a mildly cynical wombat and a statue of the god Ganesh, has this if you start reading her other work. An awful lot of everything she's done seems to have characters in common with the Gearworld, her vaguely-steampunk clockwork-labyrinth art-and-fiction setting. It's only vaguely hinted at in ''Digger'' itself.
* ''Webcomic/SugarBits'' might have done it when one of the villains summoned Red [[spoiler:and TheBigBadWolf]] from ''Webcomic/EverAfter'' to fight protagonists. However, given the nature of the ''Sugar Bits'' world and [[WordOfGod Bleedman's own words]], those two comics may or may not share an universe and this will remain unresolved until Endling, creator of ''Ever After'', will confirm it.
* Shaenon Garrity's ''Webcomic/{{Narbonic}}'' and ''Webcomic/SkinHorse'' were officially confirmed to take place in the same continuity with the introduction of [[spoiler:Artie Narbon]] to Tip Wilkin. Garrity had previously revealed in ''Webcomic/{{Narbonic}} Director's Cut'' that the main ''Narbonic'' characters, Dave, Helen, and Mell, came from three different comics she had drawn in high school and college. Mell also gets her own SpinoffBabies comic, ''Li'l Mell'', and a character introduced in that comic has now shown up in ''Webcomic/SkinHorse''. Garrity's lesser-known ''Webcomic/{{Smithson}}'' may fit into the same continuity as well; minor character Queensbury Joe appears to be the older version of Homeschool Joe from ''Li'l Mell''.
** Mel has also appeared twice in ''Webcomic/EverydayHeroes'' - once in a brief flashback where Mr. Mighty thwarts one of Helen's capers and again where she appears as Dr. Unpleasant's lawyer.
* Eli Parker created several different web projects, including ''Too Far'' (a comedy space opera webcomic), ''Darthwiki/PowerupComics'' (a StealthParody of TwoGamersOnACouch webcomics), and ''Website/TheseWebComicsAreSoBad'' (another StealthParody, this time of webcomic review blogs). Then Parker created ''Webcomic/UnwindersTallComics'', which included cameos from all of the above, establishing that they (or at least their fictitious authors) all exist in some sort of continuity.
* There was earlier hints about ''Webcomic/BobAndGeorge'' and its fancomics/subcomics taking place in the same multiverse. Ridiculous amount of cameos got finally an explanation, when Rick O'Shay and Chick-Bot appeared in the main comic to tell the [[VoidBetweenTheWorlds true nature]] of White Space. It was a demi-plane that connected all the universes together. It was later abused by [[spoiler:[[GondorCallsForAid sending all the Mega Mans and other characters into one universe, to fight Bob]]]].
* ''Webcomic/{{Glorianna}}'' and Sparky of ''Webcomic/LadySpectraAndSparky'' shared an adventure when Glorianna was briefly transported to the 21st century (while Lady Spectra ended up in Glorianna's era).
* Anna/Susan from ''Webcomic/{{Sire}}'' showed up in ''Webcomic/{{Evil Plan}}'', where it was revealed that they are the cousin of HeroAntagonist Kevin Kolton. Characters from Evil Plan and Mortifer have shown up in each others' works, and Agent/Andrew Cross shows up in both Evil Plan and ''Webcomic/{{Morphe}}''.
* In ''Webcomic/{{Spinnerette}}'' there are a few arcs centered around Hell and its inhabitants, where we meet Minerva's friends Tom, Kia, Lucretia, and Guinness, all hailing from ''Webcomic/{{Krakow}}''. Whether the ''Webcomic/{{Marilith}}'' duology and ''Charliehorse'' are also part of TheVerse is unknown.

[[folder:Web Original]]
* Any JournalRoleplay, {{MUSH}}, or similar roleplay which allows characters from multiple works of fiction must in some way explain how the crossover occurs. While the InnBetweenTheWorlds or the "[[OntologicalMystery spooky jamjar]]," in which the various characters somehow travel or are transported from their home settings into an original setting, is probably most common, some roleplays opt instead to adapt the source works into a single shared world. This is especially common for roleplays themed around a specific genre or franchise: notable examples include ''Franchise/MegaMan MUSH'', ''[[Franchise/ShinMegamiTenseiPersona Persona]] MUSH'', ''[[VideoGame/SuperRobotWars Super Robot Taisen]] MUSH'' and its SpiritualSuccessor ''Super Robot Wars MUSH'', ''Videoland MUSH'', and many others.
* ''Roleplay/TheSpectacularGargoyles'' combines the settings of ''WesternAnimation/{{Gargoyles}}'' and ''WesternAnimation/TheSpectacularSpiderMan''.
* ''Roleplay/MahouMUSH'' is a MagicalGirl-themed game set in {{Tokyo|IsTheCenterOfTheUniverse}}, the setting of which adapts many magical girl series (and a number of original player-created themes) into a single continuity. Prominent themes thus adapted include ''Anime/MagicalGirlLyricalNanoha'', ''Anime/PuellaMagiMadokaMagica'', various ''Franchise/PrettyCure''s (particularly ''Anime/HappinessChargePrettyCure''), ''Franchise/SailorMoon'', and ''Manga/ShugoChara''.
* The (In)Famous Creator/DavidGonterman, Creator/EdWood of the World Wide Web and the Internet's Most Dangerous Cartoonist; reuses characters, concepts and names so often that it more or less seems that every single thing he's ever written or drawn are all set in the same vague universe/{{multiverse}}. This may be partially intentional, but, well...
* Website/ThatGuyWithTheGlasses likes this {{trope}}, finally creating an official merging of every TGWTG-involved character during the huge anniversary brawl, and again during ''WebVideo/{{Kickassia}}'', ''WebVideo/SuburbanKnights'' and ''WebVideo/ToBoldlyFlee'', not to mention the millions of crossovers between producers. WebVideo/TheNostalgiaCritic took this a step further and incorporated Doug himself into the mix, crossing over with his vlogs.
* Franchise/TheFearMythos incorporates Franchise/TheSlenderManMythos into their canon as well as The Black Dog from folklores of the British Isles and later incorporated the Smiling Man from Blog/TheJeanetteExperience as a CanonImmigrant. The Franchise/CthulhuMythos is a part of it too, with the blog [[http://mephirevolution.blogspot.com/ Mephi]], having many of Lovecraft's creatures being a major part of the story.
* [[WMG/FriendsAndTheHighCouncil The Friends and the High Council WMG]] is an attempt to do this [[UpToEleven with every Disney-owned property]].
* A Youtuber named [=PopularMMOs=] has a series called The Crafting Dead. In the third season, he puts Dr. Trayaurus, of [=TheDiamondMinecart=] fame into the series. Before him, he puts Captain Cookie, from Epic Proportions, another series by the youtuber, became part of the story.

[[folder:Western Animation]]
* Creator/{{Disney}}, if you can believe it, did this.
** ''WesternAnimation/LiloAndStitchTheSeries'' had {{Crossover}}s with ''WesternAnimation/KimPossible'', ''WesternAnimation/TheProudFamily'', ''WesternAnimation/{{Recess}}'', and ''WesternAnimation/AmericanDragonJakeLong''. The Franchise/DisneyChannelAnimatedUniverse was codified by these crossovers.
** ''Recess''' Ashley Spinelli appeared on ''WesternAnimation/{{Fillmore}}'', adding that show to the universe.
** There was also an episode of ''Disney/{{Hercules}}'' in which Jafar and Hades cut a deal to eliminate each other's enemies, resulting in an ''Disney/{{Aladdin}}'' crossover.
** While ''WesternAnimation/DuckTales'' and ''WesternAnimation/DarkwingDuck'' were obviously part of the same universe what with both shows having Launchpad [=McQuack=], a ''Magazine/DisneyAdventures'' story known as ''ComicBook/TheLegendOfTheChaosGod'' establishes ''WesternAnimation/GoofTroop'', ''WesternAnimation/TaleSpin'', and ''WesternAnimation/ChipNDaleRescueRangers'' are part of the same universe as well.
** ''WesternAnimation/{{Gargoyles}}'' WordOfGod, Creator/GregWeisman, says it shares its universe with ''Disney/AtlantisTheLostEmpire''—or at least, each 'verse includes a BroadStrokes version of the other franchise. (This occurred when Weisman worked on an ''Atlantis'' TV {{spinoff}}—but the series, including the ''Gargoyles'' CrossThrough episode, got canned when the movie bombed.)
** The ''VideoGame/KingdomHearts'' series of video games has most major Disney worlds—or rather, explicitly AU versions of them—existing in a larger multiverse.
** The 2017 ''[[WesternAnimation/DuckTales2017 DuckTales]]'' reboot is a new universe that is planned to include Darkwing Duck, and has referred to ''[=TaleSpin=]'''s setting of Cape Suzette.
* ''Creator/HannaBarbera'' hit this trope super heavy to the point regardless of ContinuitySnarl most people assume HB as a whole has a SharedUniverse.
** It can be said while there had been years of ShoutOut from FunnyAnimal to other FunnyAnimal, ''Yogi's Birthday Party'' was an end to ''WesternAnimation/YogiBear'' that not only featured characters from his own show and supporting shows but also from ''WesternAnimation/TheHuckleberryHoundShow'' and ''WesternAnimation/QuickDrawMcGraw''.
** Not to mention a minor supporting character Bigelow Mouse had appeared on ''WesternAnimation:{{Snagglepuss}}'', ''WesternAnimation/YakkyDoodle'' and ''WesternAnimation/LoopyDeLoop''.
** When ''WesternAnimation/TheFlintstones'' came along they got in on the fun too. Yogi even showed up in person in one episode (despite being name dropped as a tv show before). When the Flintstones went to the then-present Officer Dibble from ''WesternAnimation/TopCat'' could be seen and when they went into the future it used the same design from ''WesternAnimation/TheJetsons''.
** Over in the action world the original ''WesternAnimation/SpaceGhost'' cartoon ended with TimeTravel and dimensional travel in the last six original episodes, became part of the same universe of ''WesternAnimation/DinoBoy'', ''WesternAnimation/TheHerculoids'', ''WesternAnimation/{{Shazzan}}'', ''MightyMightor'', and ''[[WesternAnimation/MobyDickHannaBarbera Moby Dick]]''
** Then in the 1970s came along and ''WesternAnimation/YogisArkLark'' brought a good chunk of the FunnyAnimal characters together into one story including the ones from Top Cat. For good measure Sawtooth from ''WesternAnimation/WackyRaces'' was there and they ran into [[WesternAnimation/MobyDickHannaBarbera Moby Dick]]. This special was followed by ''WesternAnimation/YogisGang''.
** Let's not forget the YouMeddlingKids either. When ''WesternAnimation/TheNewScoobyDooMovies'' came along, ''Franchise/ScoobyDoo'' crossed over with multiple other HB shows such as ''WesternAnimation/HarlemGlobetrotters'', ''WesternAnimation/{{Jeannie}}'', ''WesternAnimation/JosieAndThePussycats'' and ''WesternAnimation/SpeedBuggy''. Although some had referenced each other before. Also Scooby met ''Creator/LaurelAndHardy'' who had a previous HB AnimatedAdaptation, the same voice actors from that show returned but they did give them an ArtShift to match the Scooby look more than the Yogi look.
** Both ''Series/TheAddamsFamily'' and ''The Three Stooges'' (as WesternAnimation/TheRobonicStooges) got their own cartoon series following this series.
** When Scooby Doo got another show that aired in the same block as ''WesternAnimation/DynomuttDogWonder'', the Scooby gang showed up in three direct episodes of Dynomutt's show. Mumbly did likewise at the end of another episode. Even further in one episode where a singer sings the theme song from ''WesternAnimation/{{Jabberjaw}}''.
** In the last episode of ''WesternAnimation/HongKongPhooey'' we first meet Posse Impossible, who later got their own spinoff series on ''WesternAnimation/CBBears''.
** Then came ''WesternAnimation/LaffALympics'' that established all those FunnyAnimal characters and those YouMeddlingKids characters could compete in crossover Olympics. ''WesternAnimation/CaptainCavemanAndTheTeenAngels'' and ''WesternAnimation/TheGreatGrapeApe'' were both newer and connected here for the first time. Guest appearances by Fred Flintstone and Barney Rubble as well as Jabberjaw helped seal that neither CelebrityParadox nor TimeyWimeyBall could affect this trope.
** Then came ''WesternAnimation/YogisSpaceRace''. Yogi, Huck and Jabberjaw were back now crossing over with new characters such as the other Galaxy Goofups and Buford and the Galloping Ghost. This series also provided cameos from the usual Fred and Barney, Grape Ape and Quick Draw. And the not as usual, ''WesternAnimation/FrankensteinJr'', ''WesternAnimation/JanaOfTheJungle'' and the HB version of Godzilla from ''WesternAnimation/TheGodzillaPowerHour''.
** There was also ''WesternAnimation/CaspersFirstChristmas'' which used Casper the Friendly Ghost and Hairy Scary from their previous Casper series ''WesternAnimation/CasperAndTheAngels'' meeting up with Yogi and other FunnyAnimal characters.
* In the ''WesternAnimation/SouthPark'' episode "Super Best Friends", there is a brief scene of the cast of ''Series/ThatsMyBush'' in the White House, indicating that the two series (both created by Matt Stone and Trey Parker) take place in the same universe (which is particularly silly, since ''That's My Bush!'' is a live-action show). And another Creator/ComedyCentral show, ''WesternAnimation/DrKatzProfessionalTherapist''.
* There were reportedly plans to weld the canons of ''WesternAnimation/ExoSquad'' and ''Anime/{{Robotech}}'' back when the former was produced. Considering that their primary motivation seemed to be that both shows were MerchandiseDriven, your mileage may vary on whether it's a good or bad thing that this never happened. It went beyond just planning; there were figures of Robotech mecha sold in WesternAnimation/ExoSquad-branded packaging.
* ''WesternAnimation/AmericanDad''s Stan and Bullock try to stop ''WesternAnimation/FamilyGuy'''s Stewie plan to take over the world, with Stewie mistaking [[LampshadeHanging Stan for Joe]]. [[spoiler:Of course, this takes place in a virtual reality simulation, so it's debatable whether it's canonical or not.]] There have been a few other smaller cameos.
** There is a deliberate lack of crossovers between ''Family Guy'' and ''American Dad'' but they're considered to be part of the same universe. However at the end of the American Dad episode "Hurricane!", [[spoiler:the houses of Cleveland and Peter end up on the both sides of Stan's house resulting in them going into a stand-off that ends with Francine accidentally being shot by Stan]]. [[StatusQuoIsGod It's never addressed in later episodes of any of the shows]].
** Thanks to the ''WesternAnimation/FamilyGuy'' episode "Simpsons Guy", it can now be said that ''WesternAnimation/TheSimpsons'' takes place in the same universe as the aforementioned Creator/SethMacFarlane cartoons.
* ''WesternAnimation/{{ThunderCats|2011}}'' (2011), as of the episode "Legacy" features new versions of characters from ''WesternAnimation/SilverHawks'' and ''[[WesternAnimation/TheComicStrip TigerSharks]]'', all of which were action cartoon shows produced by [[Creator/RankinBassProductions Rankin/Bass]] in the '80s, sharing the same art style, writers, and voice actors. While the shows were incredibly similar and could easily be mistaken for being part of the same universe, it's only official now after twenty plus years.
* ''WesternAnimation/TheVentureBrothers'' attempted to weld itself onto the ''WesternAnimation/JonnyQuest'' canon, even going as far as to feature Race Bannon as a character in one episode, but after Warner Bros. withheld the characters in anticipation of an unreleased live-action movie, all references to Jonny Quest were quietly replaced with LawyerFriendlyCameo versions.
* Creator/RankinBassProductions is also famous for its adaptations of Christmas stories, and eventually welded many of them together in a movie called ''WesternAnimation/RudolphAndFrostysChristmasInJuly.'' Naturally there were a lot of elements that did not quite fit together -- SantaClaus, for example, had a subtly different appearance and personality in each previous special--so decisions and adjustments were made. Likewise some scenes from Rudolph and Frosty's lives were shown that differed from their own specials, but [[BroadStrokes kept the basic facts the same]].
* Originally ''WesternAnimation/StaticShock'' referenced Franchise/{{Superman}} as a fictional character but this was [[{{Retcon}} retconned]] allowing the show to be welded into the Franchise/DCAnimatedUniverse.
* ''WesternAnimation/TheCritic''[='=]s Jay Sherman once showed up to judge the ''WesternAnimation/TheSimpsons''[='=] Springfield Film Festival, though Matt Groening was so against the idea that he took his name off the opening credits for that episode. The welding is a bit awkward, since it's established that ''The Simpsons'' are a cartoon in Jay's world, but he appears twice more in Springfield.
-->'''Jay:''' ''[in a straightjacket]'' It stinks! It stinks! It stinks!\\
'''Springfield psychiatrist:''' Yes, Mr. Sherman. Everything stinks.
* ''WesternAnimation/TheTransformers'':
** In the '80s, it was broadly hinted that the original cartoon shared a universe with the ''GIJoe'' cartoon, and not-quite-as-broadly that the same was true for ''WesternAnimation/{{Jem}}'' and ''WesternAnimation/{{Inhumanoids}}''[[note]]''[[WesternAnimation/MyLittlePonyAndFriends My Little Pony]]'' was close to being the same universe with a couple scenes scrapped from ''WesternAnimation/MyLittlePonyTheMovie''.[[/note]]. This has been taken much further in the 21st century, where not only were the previous hints confirmed, but now ''every'' Hasbro cartoon from the time period has been stated to be part of the same universe, and pretty much every other Hasbro property exists within the Transformers multiverse.
** Thanks to Hasbro acquiring the IP to the characters '''[[WesternAnimation/ChallengeOfTheGoBots the Go-Bots]]''', one of the ''Transformers'' franchise's most infamous rivals, are now part of the TF multiverse. Further, the official fan club's long-running comic storyline and some new toys mean that Hasbro has retconned the Go-Bots into being just another ''Transformers'' show, with the Go-Bots having their own universal designation (something reserved for actual TF series) and Gobotron being retroactively declared as an alternate form of Primus.
* Space Ghost has become a recurring character in the Creator/AdultSwim Universe currently consistsing of ''WesternAnimation/SpaceGhostCoastToCoast'', ''WesternAnimation/AquaTeenHungerForce'', ''WesternAnimation/TheBrakShow'', ''WesternAnimation/PerfectHairForever'', ''WesternAnimation/HarveyBirdmanAttorneyAtLaw'', ''WesternAnimation/TwelveOunceMouse'', and possibly ''WesternAnimation/Sealab2021''.
* ''WesternAnimation/StevenUniverse'' crossed over with ''WesternAnimation/UncleGrandpa''; UG himself declared it to be a non-canonical, April Fools' ep. And at the end, he pulls out a checklist revealing he's visited ''[[WesternAnimation/DextersLaboratory Dexter and Dee-Dee]]'', [[WesternAnimation/ThePowerpuffGirls Blossom, Bubbles and Buttercup]], [[WesternAnimation/EdEddnEddy the Eds]], [[WesternAnimation/TheGrimAdventuresOfBillyAndMandy Billy and Mandy]], [[WesternAnimation/FostersHomeForImaginaryFriends Mac]], [[WesternAnimation/TheLifeAndTimesOfJuniperLee Juniper Lee]], the ''WesternAnimation/SWATKats'' (!), [[WesternAnimation/TheMarvelousMisadventuresOfFlapjack Flapjack]], and [[WesternAnimation/AdventureTime Finn]], with ''WesternAnimation/{{Clarence}}'' next up. (''SWAT Kats'' being included was kinda surprising, considering it debuted in 1993, before the Cartoon Cartoons, and wasn't originally for CN, but rather for sister station Creator/{{TBS}} back when they aired cartoons.)
* WordOfGod places ''WesternAnimation/TheAvengersEarthsMightiestHeroes'', ''WesternAnimation/WolverineAndTheXMen'', ''WesternAnimation/HulkVS'', and ''WesternAnimation/ThorTalesOfAsgard'' in the same universe. We have [[spoiler:Wolverine appearing as a member of both the Howling Commandos and New Avengers and the Mutant Response Division imprisoning Whirlwind]], as well as one ''Wolverine'' episode being a direct sequel to ''WesternAnimation/HulkVs''. (However, contradictions do exist, mainly in the portrayal of the Hulk and which eye Fury's eyepatch is on.)
** WordOfGod has also said that the X-Men would have shown up in Season Three [[WhatCouldHaveBeen had it not been cancelled]].
** The show's [[AllThereInTheManual tie-in comic]] (which was written by the show's creators) blatantly contradicted this, showing versions of ComicBook/ScarletWitch and ComicBook/{{Quicksilver}} that were nothing at all like their ''WATXM'' counterparts.
* In the ''WesternAnimation/TeenageMutantNinjaTurtles2012'' episode "Trans-Dimensional Turtles", it's revealed that the [[WesternAnimation/TeenageMutantNinjaTurtles1987 87 Krang]] is actually part of the Kraang gathering. He was kicked out for being an idiot. When Krang and the Sub-Prime meet, Krang is referred to as the Sub-Prime's cousin.
* ''WesternAnimation/TheSimpsons'' and ''WesternAnimation/{{Futurama}}'' started out as MutuallyFictional, but then "[[Recap/TheSimpsonsS26E6Simpsorama Simpsorama]]" happened. The later ''Simpsons'' episode "[[Recap/TheSimpsonsS27E2CueDetective Cue Detective]]" establishes that Bender is still on TheSlowPath in the Simpsons' basement. Coincidentally, ''Simpsons'' episodes "[[Recap/TheSimpsonsS23E9HolidaysOfFuturePassed Holidays of Future Passed]]" and "[[Recap/TheSimpsonsS25E18DaysOfFutureFuture Days of Future Future]]" exhibited more traits of ''Futurama''[='=]s depiction of the future (e.g. aliens living with humans on Earth) than in previous episodes depicting the Simpsons' lives in the future. There's still no explanation behind [[AmazingTechnicolorPopulation the differences in skin colors between shows]], however.
* A couch gag in ''WesternAnimation/TheSimpsons'' featured Rick and Morty of ''WesternAnimation/RickAndMorty'', thus proving that they exist in the same ''multiverse''.
* There's also more than a few cameos in ''WesternAnimation/RickAndMorty'' that show it takes place in the same continuity as ''WesternAnimation/GravityFalls''. Rick and Morty has the mug and notepad Grunkle Stan lost in a portal popping out of one of Rick's, Bill Cipher popping up on a computer screen, and Bill's ally 8-Ball dead in the Detoxifier, while the {{Defictionalized}} Journal 3 contained a silhouette of a Plumbus and a Zigerionon, as well as an encoded message left by Rick.
* ''WesternAnimation/TheLegoBatmanMovie'' (2017) takes place in a continuity that includes ''all'' of Franchise/{{Batman}}'s media appearances.
-->'''Alfred:''' Sir, I've seen you go through similar phases in [[Film/BatmanVSupermanDawnOfJustice 2016]], and [[Film/TheDarkKnightRises 2012]], and [[Film/TheDarkKnight 2008]], and [[Film/BatmanBegins 2005]], and [[Film/BatmanAndRobin 1997]], and [[Film/BatmanForever 1995]], and [[Film/BatmanReturns 1992]], and [[Film/{{Batman}} 1989]], and that weird one in [[Film/BatmanTheMovie 1966]].\\
'''Batman:''' I have aged ''phenomenally''.
* WordOfGod stated that ''WesternAnimation/MiloMurphysLaw'' was in the same universe as ''WesternAnimation/PhineasAndFerb'' from the beginning, but the shows have become more closely joined as the former goes on, with the eventual reveal that [[spoiler:Doofensmirtz is destined to invent the TimeTravel technology that Cavendish and Dakota use]].