History Main / OneDegreeofSeparation

* Another possible professional sports version, though it can't be worked out rigorously, was posited by veteran sportscaster Bob Costas in a 2016 Creator/{{ESPN}} piece on Vin Scully, who at the time of publication was less than two weeks away from retiring from the [[UsefulNotes/MLBTeams Los Angeles Dodgers]] broadcast team... after having called Dodgers games since ''1950'', when the team was still in Brooklyn.

** Start with the ThreeAmigos, Sora, Riku, and Kairi, who were raised in Destiny Islands and want to explore other worlds. Sora is accompanied by Donald and Goofy, assistants and friends of King Mickey, who later helps Riku overcome darkness and becomes his friend. Late to ''[[VideoGame/KingdomHeartsI I]]'', it is revealed that Kairi was originally from a place called Hollow Bastion, the homeworld of most ''Franchise/FinalFantasy'' characters, but also the game's main villain, Ansem, who briefly possesses Riku.
** ''[[VideoGame/KingdomHeartsII II]]'' reveals that the "Ansem" Sora defeated was not really Ansem, but was merely the Heartless of an impostor called Xehanort, who studied under the real Ansem, who is friends with Mickey. Xehanort's Nobody, Xemnas, is the leader of Organization XIII, whose members Sora battles one by one in ''[[VideoGame/KingdomHeartsChainOfMemories Chain of Memories]]'' and ''II''. Six other members of the Organization are also Nobodies of Ansem's apprentices. One of them, Axel, is part of another ThreeAmigos with the Organization's two latest members: Roxas, Sora's Nobody; and Xion, Roxas' replica who looks like Kairi. Another Kairi lookalike is her Nobody, Naminé, who was born in Castle Oblivion, one of the Organization's bases.
** Roxas himself looks like another person, Ventus, a Keyblade wielder from a decade ago. As revealed in ''[[VideoGame/KingdomHeartsBirthBySleep Birth by Sleep]]'', Ventus, a friend of Lea, Axel's human form, is the light counterpart of Vanitas, the source of the Unversed. Ventus' heart healed itself after the disastrous birth of Vanitas by merging with Sora (in the process giving Sora the ability to wield Keyblade) and that's why Vanitas looks like Sora and Roxas like Ventus. Said merging was under the watchful eyes of Master Xehanort, whom Ventus studied under. This Xehanort was not exactly the same as the current one; he was old and only gained his current form by possessing Ventus' friend, Terra. Terra once met Sora and Riku and was the person who granted Riku the ability to wield Keyblade. Terra and Ventus, by the way, are part of a third ThreeAmigos. The third member is Aqua, who created Castle Oblivion, granted Kairi the ability to wield Keyblade and a means to escape Hollow Bastion should it faced danger (hence why she ended up in Destiny Islands) and also met Sora and Riku; in particular, she gave Sora motivation to save his friends, kickstarting his adventurous personality. The amigos trained under Master Eraqus, Xehanort's blood brother. Coming full circle, Xehanort's homeworld is revealed to be Destiny Islands and the tale of his journey to become a Keyblade Master inspired Riku, leading him to suggest Sora and Kairi to leave the islands.

* The formation of Music/TheTravelingWilburys musical {{supergroup}} would likely have been dismissed as being a ContrivedCoincidence if it didn't actually happen. The story goes: Music/GeorgeHarrison and producer [[Music/ElectricLightOrchestra Jeff Lynne]], who were working on an album together, met up with Music/RoyOrbison for dinner one night, and when they finished Harrison realised that he'd left his guitar at Music/TomPetty's house and went to collect it. While they were there, Petty suggested that they use Music/BobDylan's home recording studio to work on the album, since Harrison's own home studio was back in England. Petty tagged along with the others to Dylan's house, and all the assembled musicians decided that since they already were hanging out together, they might as well jam together. The product of that session ended up resulting in their first single, which they decided was so good that it could go on it's own album, and since they had so much fun together...

* ''Franchise/BlazBlue''. Ragna and Jin/[[spoiler:Hakumen, member of the Six Heroes]] are brothers. Nu, Lambda and Noel/[[spoiler:Mu]] are [[spoiler:clones of Ragna and Jin's sister Saya]]. Saya herself is [[spoiler:the vessel of Hades Izanami, Imperator of the NOL]]. Tsubaki (Jin's love interest) and Makoto are Noel's friends from the Military Academy. Ragna, Jin and Saya were raised by Celica A. Mercury, who is the sister of one of the Six Heroes, Nine. Nine and Jubei (another one of the Six Heroes) are the parents of Kokonoe. Litchi, Roy (who later became Arakune) and Relius worked together with Kokonoe at some point. Relius is Carl's father and part of the BigBadDuumvirate along with Yuuki Terumi of the Six Heroes. Other members of the Six Heroes are Valkenhayn R. Hellsing (Rachel's butler) and Trinity Glassfille (whose soul now occupies Platinum's body). Additionally, Kagura and Makoto are heavily implied to have been FriendsWithBenefits at some point, and Kagura, Jin, Tsubaki and Mai are all part of a Duodecim family (the Mutsuki, Kisaragi, Yayoi and Hazuki families, respectively). Meanwhile, Bang has a grudge against Jin for killing his master, and Taokaka is friends with Litchi, as well as a member of a species created by attempting to [[CloningBlues clone Jubei.]]

* ''The Altered Destinies'' FanVerse is an ExaggeratedTrope due to the fact that each story in it is a MassiveMultiplayerCrossover, so DependingOnTheWriter or even a specific universe in TheMultiverse this trope could be bigger or smaller then normal. In the Baderverse for example Tenchi and Usagi are Ranma’’s cousins, Ukyo is Makoto’s Sempai, Cologne is not only Yosho’s daughter (making her either Ranma’s aunt or great aunt depending on the universe), but Ryoga’s great aunt, and that’s not even scratching the surface of just how much the characters are connected.

** Hilariously lampshaded by Axel/Lea in ''[[VideoGame/KingdomHeartsIII III]]'' in an extended SelfDeprecation rant, complaining that everyone AlreadyMetEveryone and that spells an insane amount to [[CatchPhrase get memorized]].

* ''Fanfic/ChildOfTheStorm'' takes this approach, especially with Harry: his maternal grandparents were crack SHIELD Agents who mentored Nick Fury, who was the second candidate to be Harry's godfather after being a sort of big brother to Lily Evans. Doctor Strange was his paediatrician. Wanda Maximoff is his godmother. Jean Grey is his maternal second cousin.
** Meanwhile, Clint turns out to be the grandson of Bucky Barnes and Minerva [=McGonagall=] and the first cousin (via adoption) of Clark Kent. Charles Xavier is Tony Stark's godfather. It only gets stronger and stranger from there.
** A Trope, however, as explained in chapter 48 and elaborated upon in chapter 80, is that Wanda blessed Harry with a probability warping enchantment designed to cause this at the behest of Doctor Strange, who has been manipulating events and people for millennia to unite the world against Thanos.

* In ''Anime/LoveLiveSunshine'', it turns everyone in Aqours besides [[NewTransferStudent Riko]] know each other from the past, thanks to the abundance of ChildhoodFriends. in this case, as the cast all live in a small beachside town.

** ''Literature/{{Baccano}}'': It all started in a ship, in which that ship made some humans immortal. One of those immortals eventually became a member of a Camorra group in which his closest allies [[spoiler: became immortal as well]] thanks to an old, immortal man from the ship, a man from another crime family, as well as two thieves. Those two thieves would later on go to a train ride where they befriend a young-looking boy who is also one of the immortals from the ship; and a young gang leader who happens to be under the radar of a hitman from another crime family, whose plans get hijacked by a terrorist group led by one of the immortals from the ship. Said immortal's daughter happens to get the attention of a young conductor [[spoiler: who happens to be a serial killer who's been killing several people in the train; as well as the adoptive brother of the Camorra group's closest allies. The conductor and his brothers]] then come across the sister of the man partially responsible for making the the Camorra group and their allies [[spoiler:immortal]]. Apparently, she also takes in the young gang leader, his gang and the immortal's daughter from the train; and at one point, she also came across the two thieves. [[JigsawPuzzlePlot Confused yet?]] [[LongRunner Because that's just what the first 4 volumes (and the anime) have covered]].

* ''Fanfic/JoJoNewUniverse'': The main characters of ''[=JoJo=] New Universe: Steel Ball Run'' are all connected to other characters in the universe. The protagonist Sadao Kujo is [[Manga/JoJosBizarreAdventureStardustCrusaders Jotaro Kujo's father]]. The BigGood and TheTeamBenefactor [[AdaptationalHeroism Funny Valentine]] is not only the GoodCounterpart of his [[Manga/JoJosBizarreAdventureSteelBallRun canon self]] but also [[Manga/JoJosBizarreAdventureStoneOcean Narciso Anasui's]] uncle. OfficialCouple Asahi [[WesternAnimation/MyLittlePonyEquestriaGirls "Sunset Shimmer"]] Nichibotsu and Ryusei Ito [[EveryoneWentToSchoolTogether were Noriaki Kakyoin's former classmates]], while Sunset is cousin to [[RelatedInTheAdaptation Himari "Fluttershy" Utsukushicho]]. James Brown is the son of [[Manga/JoJosBizarreAdventureBattleTendency politician Smokey Brown]]. Radames Avdol is the merchant brother to fortune-teller and future crusader Muhammad Avdol. Antoinette Dupont is the late Sherry Polnareff's best friend and was trained to fight by Sherry's brother Jean-Piere. AmnesiacHero Rudy was a close friend of Iggy the Boston Terrier. And Sanji Matsumoto is the [[OCStandIn flesh-out adaption of the man that saved Josuke and Tomoko Higashikata from a snowstorm]].

* ''Manga/CaseClosed'' is a long-running mystery series where backstories are usually key revelations--but most of the time, good and bad guys alike are secretly intimately connected to a ridiculous degree, often by complete coincidence. For example, here are instances of this trope regarding only the odd connections of Kudou Shinichi, the main protagonist: Early in the series, Shinichi finds a rival in Kaitou KID, a thief he'd never heard of prior to encountering him during a "joke" heist, and whose true identity he still does not know. But despite their meeting being completely coincidental, with neither having any knowledge of any personal connections, KID's father was Shinichi's mother's mentor and Shinichi's father's rival and best friend, and in the thief's [[Manga/MagicKaito own series' manga/anime adaptation]], Shinichi's surrogate uncle, Agasa, is heavily implied to be the long-time friend of Jii, KID's surrogate grandfather, as well as the unwitting supplier of the gear Jii gives KID to help with his heists. Further, despite Shinichi's encounter with [[BigBadEnsemble the Black Organization]] being pure bad luck, ex-member Haibara's seeking him out for protection being completely unrelated to who Shinichi actually is, and the Black Org having no idea Kudo Shinichi is even still alive to be involved in any of this, the assassin sent after Haibara is the best friend of Shinichi's mother, a friendship she made during her mentorship under Kaito's father. Not only that, but it's the same assassin whose life Shinichi and Ran completely coincidentally encountered and saved while said assassin was undercover as an alleged serial killer, completely ignorant of her real appearance or identity, ties to Shinichi's family, or the Black Org. And after saving that "serial killer," they encounter Akai Shuichi, the FBI agent who would later partner with Shinichi after Shinichi, again entirely by coincidence, gets himself involved with the Black Org. As it turns out, Shinichi randomly met the entire Akai family (sans the father) when he was on a family beach trip as a child before any of this happened, and became Akai Shuichi's little sister's inspiration to be a detective. This just covers a few connections with ''the main character.'' The extended cast's connections are just as crazy.

** Lelouch and Suzaku's relationship is ''central'' to the series, not just a coincidence (check how the beginning and ending revolve around ''their'' relationship), and both are royalty -- Lelouch literally, Suzaku [[HereditaryRepublic more or less]] - so it's no surprise that they're well-connected. Anya and Jeremiah are where they are due to the same thing that connects them to Lelouch - Anya [[spoiler: gets the piloting ability to be a Knight of the Rounds ''because'' she's possessed by Marianne]], and Jeremiah and everyone else who cared about [[spoiler: Marianne, or Lelouch and Nunnally, came to Area 11 specifically because Lelouch and Nunnally had supposedly died there - including Clovis, as revealed in an audio drama]]. Lloyd [[spoiler: gets engaged to Milly]] ''because'' the Ashford family has Marianne's knightmares, which they have because they were connected to her, which is also the reason they took in Lelouch and Nunnally. Legitimate coincidences include Euphie meeting Suzaku [[MeetCute unless she planned it that way]], Lloyd meeting Suzaku, Villetta - Jeremiah's second - getting her Knightmare stolen, and then [[spoiler:being rescued by Ohgi]], Lelouch's classmate Nina [[spoiler: has a crush on Euphie and being the one to invent Britannia's superweapon]], and a few others - plenty of DiabolusExMachina to go around for both protagonists. But the level of connectedness in general is pretty typical of monarchies, making it a JustifiedTrope.

* In ''Anime/LoveLiveSunshine'', it turns everyone in Aqours besides [[NewTransferStudent Riko]] know each other from the past, thanks to the abundance of ChildhoodFriends. Justified in this case, as the cast all live in a small beachside town.

** A JustifiedTrope, however, as explained in chapter 48 and elaborated upon in chapter 80, is that Wanda blessed Harry with a probability warping enchantment designed to cause this at the behest of Doctor Strange, who has been manipulating events and people for millennia to unite the world against Thanos.

** Justified in Niven, Pournelle, & Flynn's ''Fallen Angels'' as many of the characters are connected through science fiction fandom.

* Used extensively in Creator/MegCabot's ''Boy'' series. Each book has (mostly) different characters, but they all seem to have known each other, some for justified reasons (a lot of them do work at the same company, after all), but others through completely random coincidence. Notable examples include Stacy Trent turning out to be Mitch Hertzog's sister, or Amy Jenkins, annoying HR rep to Mel and later [[CorruptCorporateExecutive evil]] [[MeanBoss boss]] to Kate just happening to have somehow screwed Jane over in the past as well. Also, Nadine's fiance Tony from the first book just happens to show up and hire Ida Lopez to work in his restaurant in the second, and apparently Aaron Spender and Cal Langdon both slept with Barbara Bellerieve.

* ''Literature/HarryPotter ''

* In ''Literature/Rule34'' by Creator/CharlesStross, the three main characters are Liz, a police officer who is called off her investigation of where unlicensed 3D printers are getting their feedstock to investigate the murder of Michael Blair; The Toymaker, the local head of an international 3D-printer-based crime organisation who is in Edinburgh to recruit Blair; and Anwar, an ex-con (previously arrested by Liz) who has become honorary consul to a tiny {{Ruritania}} which mostly involves doling out "bread mix" to people who just happen to be legmen in the Toymaker's organisation. In addition, Anwar's mother-in-law turns out to be Blair's housekeeper (and [[spoiler: his cousin is a later victim]]), and the Toymaker propositions Liz's casual girlfriend (who, as a financial investigator, is ''also'' WorkingTheSameCase). And the German policeman who liaises with the case due to a similarity to other murders across the EU has previously worked with Liz. It reaches the point where the characters themselves are trying to figure out what's going on, because it ''can't'' all be a coincidence. And it turns out [[spoiler: it's not - everyone involved is being manipulated by an AI designed to use behavioural psychology and the internet to "nudge" people into not breaking the law, but which decided it would be more efficient to use behavioural psychology and the internet to kill lawbreakers.]]

* ''Literature/GrandmasterOfDemonicCultivationMoDaoZuShi'': Pretty much every plot-relevant character is directly connected to each other by [[ReallyGetsAround blood]], [[PerfectlyArrangedMarriage marriage]], [[BloodBrothers sworn brotherhood]] or [[FamilyOfChoice adoption]]. Somewhat {{justified}}, as the story revolves around the five most notable clans, akin to nobility in the cultivation world, and it is common for nobles to be all related to each other.

* In ''Literature/HaruhiSuzumiya'', despite Kyon being [[OrdinaryHighSchoolStudent completely, explicitly]] unconnected to any of the weirdness going on, his ChildhoodFriend turns out to be the previous [[spoiler:holder of an incredible unique power]] whose next inheritor Kyon would befriend, solely by chance, several years later. Most other examples of the trope are justified in that they result from [[spoiler:Haruhi being God and unconsciously warping the universe to be more fantastical]], but this example she has absolutely nothing to do with. It's just how the dice fell.

* ''Series/GameOfThrones'': Normally justified, as the relatively small size of the noble class in Westeros means most families will have met or at least heard of each other.

* In ''VideoGame/PlanescapeTorment'', you come across a rather staggering array of people with one degree of separation from one or another of The Nameless One before he got amnesia, including all your party members [[spoiler:except Nordom and Fall-From-Grace]]. {{Justified|Trope}} because not only is the game about a personal quest for identity and therefore you will logically be hunting down people with a prior connection to you, but you actually have a supernatural ability to bind people to yourself, connecting their torment to your own.

* ''Webcomic/SluggyFreelance'' has way too many characters for them all to be connected, but there are many examples of completely random connections, especially between the different alternative realities. This is partly justified in that the dimensions are indeed parallel and often have many similarities, but only partly. Often it's more that the reader can notice the coincidences, not so much the characters, because different people meet different people.

** ''Literature/{{Baccano}}'': It all started in a ship, in which that ship made some humans immortal. One of those immortals eventually became a member of a Camorra group in which his closest allies [[spoiler: became immortal as well]] thanks to an old, immortal man from the ship, a man from another crime family, as well a two thieves. Those two thieves would later on go to a train ride where they befriend a young boy who is also one of the immortals from the ship; and a young gang leader who happens to be under the radar of a hitman from another crime family, whose plans get hijacked by a terrorist group led by one of the immortals from the ship. Said immortal's daughter happens to get the attention of a young conductor [[spoiler: who happens to be the adoptive brother of the Camorra group's closest allies]]; who then comes across the sister of the man partially responsible for making the the Camorra group and their allies [[spoiler:immortal]]. Confused yet? [[JigsawPuzzlePlot Because that's just]] [[LongRunner what the first 4 volumes (and the anime) have covered]].

* ''Literature/{{Durarara}}'': Everyone--no, really, ''everyone''--knows Mikado somehow. Leader of the Yellow Scarves? [[spoiler: his best friend]]. The [[spoiler:Demon Sword and chat room troll]] Saika? [[spoiler: possesses the girl he has a crush on]]. Urban legend Dullahan on a motorcycle? [[spoiler: one of his chat room friends]]; the other is [[ChessMaster Orihara]] [[ManipulativeBastard Izaya]]. And Harima Mika, [[spoiler: the girl made to look like Celty's head]], sits behind him in class.

** Lelouch and Suzaku's relationship is ''central'' to the series, not just a coincidence (check how the beginning and ending revolve around ''their'' relationship), and both are royalty -- Lelouch literally, Suzaku [[HereditaryRepublic more or less]] - so it's no surprise that they're well-connected. Anya and Jeremiah are where they are due to the same thing that connects them to Lelouch - Anya [[spoiler: gets the piloting ability to be a Knight of the Rounds ''because'' she's possessed by Marianne]], and Jeremiah and everyone else who cared about [[spoiler: Marianne, or Lelouch and Nunnally, came to Area 11 specifically because Lelouch and Nunnally had supposedly died there - including Clovis, as revealed in an audio drama]]. Lloyd [[spoiler: gets engaged to Milly]] ''because'' the Ashford family has Marianne's knightmares, which they have because they were connected to her, which is also the reason they took in Lelouch and Nunnally. Legitimate coincidences include Euphie meeting Suzaku [[MeetCute unless she planned it that way]], Lloyd meeting Suzaku, Villetta - Jeremiah's second - getting her Knightmare stolen, and then [[spoiler:being rescued by Ohgi]], Lelouch's classmate Nina being the one to [[spoiler: invent Britannia's superweapon]], and a few others - plenty of DiabolusExMachina to go around for both protagonists. But the level of connectedness in general is pretty typical of monarchies, making it a JustifiedTrope.

* Played straight, but almost to the point of parody in ''Theatre/TheImportanceOfBeingEarnest'': Algernon and Jack are friends from the city, Jack wants to marry Gwendolen, who is Algernon's cousin and the daughter of Lady Bracknell. That's all well and fine, but Jack has no biological parents (high society no-no), having been abandoned at a train station as a baby. It turns out that Jack's ward Cecily, who is Algernon's love interest, is being taught German by Ms. Prism, the former employee of Lady Bracknell and also the woman who accidentally abandoned Jack as a baby. It's then revealed that therefore Jack is Lady Bracknell's nephew, Gwendolen's cousin and Algernon's brother. Ironically, this is one of the few times where characters turning out to be related actually leads to a [[KissingCousins happy ending]]; it not only gives Jack a respectable background, but since he's the son of her beloved sister, Lady Bracknell can't very well object to him.
* Played straight in ''Theatre/{{Wicked}}'' where every single character of relevance in the play can be tied to Elphaba. Not unreasonably so since she's the Wicked Witch, but let's sum up. Her teacher is the Wizard's Dragon, her sister is the Wicked Witch of the East, her manservant is a school chum, she saved the Cowardly Lion, the Scarecrow is [[spoiler:her transformed boyfriend,]] the Wizard [[spoiler:is her father]], and so on and so forth.

* One ''Webcomic/{{xkcd}}'' strip shows the dead rising... and Cueball and several other mathematicians immediately rush to the grave of Paul Erdos (see the Real Life section) to [[InvokedTrope ask him to sign their papers]].

** This is especially evident in the Dressrosa arc, where many of the participants in the Tournament [[spoiler:for Ace's devil fruit]] have a connection to characters that connect them to Luffy.

* In ''Playing By Heart'', this is TheReveal -- except for some ArcWords, there's no hint of any connections other than the obvious ones, until the end.

* ''Fanfic/DragonBallZDynasty'': In chapter 138, Gohan finds out that the lawyer that his classmate Erasa has been shadowing is Lazuli Lazarus, who he knows better as Android 18.

* Happens in ''WebAnimation/HelluvaBoss'' with Chaz Thurman, a Shark Demon who worked for Moxxies' father Crimson back when Moxxie was an [[MafiaPrincess aspiring Mafioso]] until a robbery-gone-wrong resulted in Moxxie landing in the clink. Later on, it's revealed that Chaz ended up starting a relationship with Millie until it went sour. By the time the three of them meet up again, Moxxie and Millie have been HappilyMarried to each-other and joined the Immediate Murder Professionals. [[LampshadeHanging Lampshaded]] by their boss Blitzo.

* ''Literature/TheWestingGame'': On the surface, the sixteen heirs of Sam Westing (whom he claims as nieces and nephews) seem to have been randomly chosen and have no connection at all to him, but as the story progresses all those connections are revealed: the Wexlers really are blood kin through Grace (except her husband Jake, obviously), Theo and Chris's dad used to date Westing's daughter Violet, Flora Baumbauch made Violet's wedding dress, Mr. Hoo was a competitor who accused Westing of stealing an invention of his, Judge Ford's family used to work for him and he funded her schooling, Crow [[spoiler:is his wife]], Otis Amber [[spoiler:is the private investigator he hired]], and Sandy [=McSouthers=] used to work for Westing [[spoiler:and is actually one of Westing's aliases.]] The one exception is [[spoiler:Sydelle Pulaski, who was a case of MistakenIdentity: Otis was supposed to find a ''Sybil'' Pulaski, a friend of Violet's.]]