->''"griffon8 pointed out that I've been writing as though Shizune and Misha shared a double room rather than the singles every other student seems to use. Call it artistic license; it doesn't interfere too much with established canon (I think) and isn't even that critical to this story anyways."''
-->--'''Author's note''', ''[[VisualNovel/KatawaShoujo From Shizune's Perspective]]''

While it's very difficult for a story with a big audience to ever reach a consensus, occasionally a ''single'' fact or aspect of the series is modified enough in FanFic vs. the original story that its absence or modification becomes notable within the fandom. This may escalate to the point where fanfics do not bother to note the change in any tags or clarifications and that even sticklers for continuity are generally not bothered by it. This will also happen much more quickly in a tightly-knit fan community. Conversely, it occurs much slower if there's a big FanDumb community, unless they're being [[FandomBerserkButton actively trolled]].

Note that "mechanical" changes to make things work in a text medium (reworking a gag because describing a visual isn't funny) or changing an ending because the story covers that period ("soft" [[AlternateUniverse AUs]]) don't count. The change must be common enough to get fan recognition, deliberate rather than an outright mistake or forgetful {{Flanderization}}, but not actually overshadow the original version of the story (as {{fanon}} can and does).

Common flavors include the following, and may occur separately or together:
* [[PatchworkFic Canon mixing]]: Borrowing a characterization or concept from another version of the story because they were more popular/interesting/notable even if the rest of the universe appears "normal", or simply more elaborated upon. Frequent in series with many [[AlternateContinuity Alternate Continuities]] (and thus little sense of "true" canon), especially if those other versions [[NoExportForYou aren't as necessarily so well known as others]]. In extreme cases, writers may create FridgeBrilliance or invoke BroadStrokes outright to explain how even ''explicitly'' different versions are both valid interpretations simultaneously.
* [[FanonDiscontinuity Continuity tweak]]: Avoiding or reworking something that just didn't fly in the audience's mind to make more sense or be less stupid. Again, can become a Fandom Theory with enough support.
* Personality tweak: The toning down/[[{{Flanderization}} up]] of a character's personality within "acceptable" bounds, said bounds usually based on... [[ShapedLikeItself how people write the character in fanfics frequently]]. Popular with low-emotive characters who are otherwise difficult to write for or who have a popular line (count the usages of BigDamnHeroes in ''Series/{{Firefly}}'' and then in Firefly Fics, for example).
* Memetic Mashing: The writer incorporates the MemeticMutation of a character into the work under the challenge of making it mesh believably with the established characterization. Difficult and prone to become very in-jokey if done badly, excellent {{Fandom Nod}}s when done right.
* [[{{Jossed}} Retroactive Discontinuity]]: A special subset of this where an aspect of a fic that started out canon becomes a break from canon by events of future seasons/books/what have you. Either someone dies, or someone new is introduced, or something new is revealed, what have you, but something happens which changes the canon in ways not reflected in the fanfic.

Compare FixFic, where the story tends to focus ''entirely'' on addressing problems. Also compare {{Woolseyism}}.
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!!Examples
* Since the name of the series is ''WebAnimation/DeathBattle'', it's generally accepted for the characters to fight to the death, regardless of their status on killing in their original series, as well as a few tweaks in strength and defense to avoid a completely one-sided fight.
* In ''Series/BuffyTheVampireSlayer'' fics, especially during Season 6 fics and Post-Chosen Fics, personality tweaking is loved. A common way to get rid of Kennedy in Post-"Chosen" fics is for her to be [[DieForOurShip a cheating bitch, an abusive bitch or a]] [[BreadEggsBreadedEggs cheating, abusive bitch.]] A common thing to do with Buffy is take her Season 6 angst and make her an EmotionlessGirl faking emotion.
* ''Anime/NeonGenesisEvangelion'': Mostly personality tweaking, like openly emotive Rei and more extroverted Shinji are the biggies; while never as popular as the show, some fans automatically assume the writer is using their manga counterparts instead. This might die out seeing as they've become official depictions in ''RebuildOfEvangelion''.
* ''Franchise/SailorMoon'': Huge amounts of canon mixing, depending on what area of the world you lived in had in the way of SmallReferencePools and access to whatever source material was handy.
** Zoicite: The harpy-like, melodramatic female incarnation from TheNineties Creator/DiC English dub is widely more popular than the original, and tends to show up if the Dark Kingdom is featured.
** Rei: Types A & B — Writers are much more likely to use her depiction in the original [[Manga/SailorMoon manga]] (stoic, borderline {{Tsundere}}, [[MemeticMutation "kinda gay"]]) than the one in the [[Anime/SailorMoon show]], even though the ''backstory'' for the favored depiction was not used there. In addition, due to the lines in the dub [[ValuesDissonance sounding very odd to those not familiar with Shinto mysticism]], Rei was popularly depicted as having outright supernatural powers, something the [[NewPowersAsThePlotDemands original anime only played with]].
** Makoto: Fanfic authors, especially male ones, downplay her whole [[OnceAnEpisode obsession with her former ''senpai'']]. Ironically, some fans disliked the Canadian dub for putting ''back'' references to a similar obsession with her femininity which had previously been avoided, because it made her "less cool" (incidentally making the ''official'' [[Series/PrettyGuardianSailorMoon live action series]] invoke canon mixing).
** Haruka: She [[AdaptationDyeJob might have whiter hair than expected]], or be less combative or snobby (as seen in the manga) if the author is intending to make the Sailor Team more inclusive. Writers [[InternetBackdraft brave enough]] to use her "Amara" incarnation often rationalize her as simply a sort of "younger" prototype who is still in an ambiguous (but inevitable) relationship with her partner, discovering herself, [[BiFauxnen play down her fashion]] choice, and compensate by making her a lot more sexually open.
** Michiru: Usually hit pretty hard with the CastSpeciation hammer in regards to any traits she shares with Ami. She's also a musician OR a painter, but not both, under the idea it'd make her too idealized.
* ''LightNovel/DirtyPair'': Most fanfic tends to be set in a continuity that's a varying mix of the classic anime and Adam Warren's "[[{{Animesque}} amerimanga]]" version, usually with the most memorable characters from both ([[DaChief Goulet]], [[RobotBuddy Nammo]], [[DarkActionGirl Shasti]] or [[IntrepidReporter Cory Emerson]], for instance). The psychic powers from the novels may also appear. ''Flash'' is either retconned as a GenerationXerox in the future, or alternately as just {{Outdated Outfit}}s they wore when they were younger.
* ''TenchiMuyo'': The author's favorite characters or plot points from the many alternate ''Tenchi'' continuities get brought into the OVA universe. (This most frequently means [[EnsembleDarkhorse Kiyone Makibi]] — and no, Noike doesn't count.)
* ''Manga/AxisPowersHetalia'':
** Personality tweaking, in most cases. One example is how many fics take Japan's occasionally hinted-at {{Otaku}} and CovertPervert traits in canon and play them up until he becomes a full-blown [[YaoiFangirl Yaoi Fanboy]] and/or conniving [[ShipperOnDeck matchmaker]] for the main couple featured in the fic, most likely because he's one of those low-emotive characters difficult to write for.
** In fanfics that deal with the DarkerAndEdgier implications of a series set in UsefulNotes/WorldWarII, Germany will nearly always be shown as either being lied to by his [[UsefulNotes/AdolfHitler his boss]] about everything that's going on, or that he knows but is powerless to stop it. Italy and Japan may have this happen to them as well (depending on how the author is going about things), but Germany is pretty much consistently shown that way.
* Very common in ''VideoGame/{{Touhou}}'', and also expected, since the series ''runs'' on AlternateCharacterInterpretation and MemeticMutation
* ''WesternAnimation/TeenTitans'' fics in terms of which Robin is in the series. Some have Tim Drake and others have Dick Grayson, which may lead to a change in personality (depending on how familiar the writer is with the comics) and sometimes even a change in name. (Nobody wants to have a character named [[HaveAGayOldTime Dick]]). It is hinted in the show, and confirmed in the tie-in comic, to actually be [[spoiler: Dick Grayson]].
* ''Anime/YuGiOh'':
** Don't be surprised if a fanfic has all those ancient spirits have their own body, and don't expect it to be explained. That said, not everybody considers this an ''acceptable'' break from canon.
** {{Lampshaded}} in [[http://www.fanfiction.net/s/4583644/6/Not_the_Usual_Kaiba this fic]]:
-->"Other than Yugi's long-lost cousin, Yami, mysteriously showing up a few months ago…"
** Also in, ''FanFic/DecksFallEveryoneDies'', Yami has a separate body. There are hints that this will be explained, though.
* ''Franchise/TeenageMutantNinjaTurtles'':
** Donatello is often written as insomniac and addicted to coffee, and as always falling asleep at his work bench or computer as he tries to solve some problem or challenge.
** Fanfics based on the 1980s cartoon tend to downplay or outright ignore Raphael's characterization as the MotorMouth DeadpanSnarker in that show and make him more like the [[TheBerserker violent]] [[HairTriggerTemper hothead]] he is in all other continuities.
* In ''TheGunganCouncil'', continuity is tweaked all around, yet not always to get rid of disliked events in Franchise/StarWars canon. Alderaan still exists, former Vongformed planets show little to no signs of ever being in such a state, and the Star Forge is still lurking in space.
* All over the place with ''WesternAnimation/AdventuresOfTheGalaxyRangers'', usually cranking up the DarkerAndEdgier tone, playing some of the more unsettling aspects completely straight, or offering some {{Deconstruction}} and {{Reconstruction}} behind the characters and universe.
* ''Film/{{Tron}}''-universe fanfic will work with mixed canons (in the form of porting in aspects of the [[CanonDiscontinuity discredited sequel]], ''[[VideoGame/TronTwoPointOh Tron 2.0]]'' (it helps that both timelines say Flynn and Tron vanished under mysterious circumstances) and continuity tweaks (often in the form of a "Flynn and[=/=]or Clu lives" scenario).
* The death of [[spoiler: Castiel]] at the beginning of Season Seven of ''Series/{{Supernatural}}'' has led to so much continuity tweaking it's kind of mind-boggling.
* In the ''VisualNovel/KatawaShoujo'' fanfic "From Shizune's Perspective," which was written prior to the full game's release, Shizune and Misha, as well as Rin and Emi share rooms. In the full game, all the rooms appear to be single ones, although Hisao never goes to Shizune or Misha's rooms. Shizune and Misha sharing a room becomes relevant when Shizune, looking for Misha and Hisao, enters her room [[spoiler:[[RelationshipReveal and finds them having sex]].]]
* ''Franchise/{{Pokemon}}'' has several variations:
** It is not uncommon for fanfic writers to combine the ''Manga/PokemonSpecial'' manga and the [[Anime/{{Pokemon}} anime]] into the same universe. Considering the extreme AlternativeCharacterInterpretation some characters have received between the two continuities, this can become quite the MindScrew. Similarly, stories in the [[VideoGame/{{Pokemon}} video game]] {{verse}} will often have the characters be indistinguishable from their manga counterparts, to the point where the only evidence that these are ''not'' manga fics consists of very subtle clues.
** In stories which feature the anime only, expect the Continuity Tweak variety. Often the writers will ignore ComicBookTime and have Ash be a teenager by the time of the setting.
* ''Series/{{Smallville}}'' fan fics commonly ignore the season eight finale, ''[[AntiClimaxBoss Doomsday]]'', and [[DorkAge season nine]], unless the work in question thrives solely on angst.
** For Chloe/Oliver shippers, the fact that they [[StrangledByTheRedString got together sexually in two episodes]] is usually ignored in favour of a long road to build their relationship...[[FridgeHorror despite Chloe is married to Jimmy not long before that.]]
** Talking about Jimmy, he is flat-out ignored by other shippers in general.
* Many ''Franchise/{{Transformers}}'' fanfics involve PatchworkFic due to the huge amount of ContinuitySnarl - people use their favorite personality, even if that wasn't how they were defined in this continuity. Hasbro seemed to catch on with this with Transformers Prime, mixing the most popular parts of continuities, which is how Starscream became birdlike and competant, but nonetheless a whiny and treacherous AlphaBitch who's nothing like as smart as he thinks he is.
* ''VideoGame/GoldenSun'': Retroactive discontinuity affects most romantic fic concerning the first game's heroes, as ''Dark Dawn'' featured their offspring by unknowns (with the exception of Isaac, who married Jenna but [[MissingMom seems to have since split]]). Whether these pairings were completely debunked or have ended up as {{Dry Docked Ship}}s is a matter for [[FanWank academic debate]].
* Several ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' based fan works dwell into this, given that several story set-ups can retroactively become invalid in canon as the series goes on. For example:
** ''WebAnimation/TurnaboutStorm's'' basic storyline was completed before anything beyond the first season was broadcasted, which inevitably created contradictions with the Equestrian side of things as the series was made[[note]]Such as the reencounter with Trixie[[/note]]; thus anything from season 2 onwards is assumed as non-canon for the crossover. Curiously enough, this problem isn't as serious for the ''Franchise/AceAttorney'' side of things, since the events neatly fit between the second and third games.
** [[http://mspfanventures.com/?s=484&p=223 This page]] of ''Webcomic/{{Hoofstuck}}'' clearly states that it was added prior to the airing of "[[Recap/MyLittlePonyFriendshipIsMagicS2E19PuttingYourHoofDown Putting Your Hoof Down]]," in which Fluttershy dumps a cartload of garbage on Bon-Bon's head.
** ''FanFic/TheNuptialverse'' was started shortly after the season 2 finale, and was planned out long before season 3 started. With that in mind, the author has announced he intends to cherry pick aspects from that season that work with his plans, and ignore everything else (he's even posted a list of what he's planning on doing).
* The world that ''Fanfic/JusticeSocietyOfJapan'' takes place in takes place in has a bit of Post-crisis DCU (in that superheros have been around for decades, and the Justice Society of America exists) and a bit of the New52's DCU (Justice League Dark exists, Calender Man is a news anchor, {{Superman}} and WonderWoman are in a relationship). There's a heck of a lot of canon tweaking in regards to the other series used in the fic, most notably ''VideoGame/{{Xenoblade}}'' and CodeGeass.
* Though already implied months earlier by the ''Series/DoctorWho'' series 7 finale "The Name of the Doctor", the mini-episode "The Night of the Doctor" definitively changes a lot for fanfic based on the Time War and who actually fought in it. [[spoiler:Though the Creator/JohnHurt incarnation specifically renounces the name "Doctor"]], meaning Creator/ChristopherEccleston is still technically the ninth incarnation to go by the name "the Doctor", this still doesn't change that Creator/PaulMcGann's Eighth Doctor regenerated to [[spoiler:''become'' the "warrior" played by John Hurt that would fight in the War (and not Eight, as was initially assumed)]], as [[spoiler:throughout his eighth incarnation, the Doctor]] did little more than help on the side, deliberately avoiding being a part of the Time War until he realised how much the universe and all of creation was at stake [[spoiler:and chose what sort of man to regenerate into, thanks to the Sisterhood of Karn]].
* The bitter aftertaste of the ''VideoGame/MassEffect3'' ending not only launched dozens of [[FixFic Fix Fics]] suggesting different alternate endings, it also became common or even expected to ignore the official endings in sequel fics, which typically follow a Shepard who defeated the Reapers, survived, and left a less thoroughly ruined galaxy in their wake.
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