History Main / SixthRangerTraitor

** Dusk, an elf paladin who told the group she was close with Fearne's long-lost parents and was suffering from some memory loss after being in the Feywild, was later revealed to be the Unseelie changeling Yu, who was hunting Fearne's parents down over their theft of the Moontide Crown and used Fearne to lure them out of hiding.
** After Bells Hells was split up across Exandria in the wake of the Apogee Solstice, Orym, Ashton, and Laudna ended up in Issylra with three strangers, Deni$e, Prism, and Bor'Dor. After telling everyone he was a simple shepherd who never had magic before he met the group, Bor'Dor was pressured by Deni$e into confessing his lies, immediately attempting to kill the group and revealing that he was one of the Ruby Vanguard who was fighting ''against'' Bells Hells on the Apogee Solstice.

* In the ''WebVideo/YogscastMinecraftSeries'', specifically ''[=MarsQuest=]'' [[spoiler:LetsPlay/{{Sjin}}]] joins up with LetsPlay/LewisBrindley, LetsPlay/SimonLane and LetsPlay/DuncanJones to get to Mars and rescue the captive [[spoiler:LetsPlay/{{Sips}}]]. Once the goal is achieved, he tries backstabbing Team J.A.F.F.A, but this fails ''horribly''.

!!Examples:

Like the SixthRanger, The Sixth Ranger Traitor is its ''own'' villainous counterpart, instead reflecting the member of the group who betrays the others, either by pulling a HeelFaceTurn, [[HeelFaceMole faking one]], simply for their own ends, or on rare occasions [[BrainWashed against their will]].

* ''Film/{{The Avengers|2012}}:'' Hawkeye, an archer, the sixth member of the Avengers, who had no speaking lines prior to this film, is mind-controlled by [[BigBad Loki]] and fights for him until the third act of the movie. Hawkeye is particularly dangerous because of his knowledge of SHIELD protocols and weaponry, particularly the weak points thereof.

* ''Film/{{Eternals}}'': The Eternals consider one another family. However, [[spoiler: Ikaris]] is so troubled by the idea of saving Earth from [[PlanetDestroyer the birth of a Celestial]] that he kills [[spoiler: their leader, Ajak]], in hopes of replacing her, which would allow him to keep the plan from the rest of the group and ensure all goes according to their original orders. When that fails, he attempts to kill any member of the group who works against the Celestial's emergence. It proves a difficult fight as [[spoiler: Ikaris]] was their Second-In-Command and knows them quite well. He is also aided by [[spoiler: [[TheBabyOfTheBunch Sprite]]]] who has Loki-like powers of illusion and misdirection.

** After the combined US and Cuban militaries attempt to kill the Mutant squad that has just kept the two countries from initiating what promised to be a costly and destructive war, [[spoiler: Magneto and Raven]] decide it's dangerously naive to continue to work with the CIA-backed team. [[spoiler:Magneto]] will go on to use the leadership skills he learned from Charles and the increased abilities Charles helped him hone to establish the ''Characters/XMenBrotherhoodOfMutants'' which will frequently clash with the X-Men.

[[folder:Anime & Manga]]
* In ''Manga/AttackOnTitan'', Floch Forester is a late arrival to the cast, having been a classmate of the main characters that did not enlist in the Survey Corps. He has a change of heart and decides to switch branches to begin working with his old classmates and ''seems'' to be a RedShirt in the making. Instead, [[spoiler: he's the SoleSurvivor of the suicide charge against the Beast Titan]]. After the TimeSkip, he quickly establishes himself as a TokenEvilTeammate that clashes with Jean over [[WouldHurtAChild ethics]] and eventually betrays the Survey Corps entirely as TheDragon to [[spoiler: Eren's radical Yeager Faction]].
* ''Anime/CorrectorYui'' - One of the nearest Yui's friends was the true [[TheChosenOne Chosen One]] to be the titular Corrector, but I.R. chose Yui because an error later explained she was then infected by Grosser [[spoiler: its Haruna, and no, its not "a hidden grudge" it was pure MindControl like it was later demonstrated with Shun]] before being recruited after Inukai told everyone in the group about it, then after she tried to leave the group (cause Yui [[StatusQuoIsGod was better for the Correctors]]) Grosser takes her and [[BrainwashedAndCrazy turned her against Yui]], it was fixed on the next episode but she didn't return as a Corrector until the next season.[[spoiler: Haruna is eventually cured by Yui herself in an IKnowYoureInThereSomewhereFight, goes under temporal retirement (she was still remaining as MissionControl) and, in the second season, [[HesBack she rejoins]] the team as SixthRanger]].
* In ''Manga/DeathNote'', Light Yagami joins the secret police taskforce in charge of finding and stopping Kira, a brilliant but crazy serial killer who's using an ArtifactOfDoom to anonymously murder anyone he deems evil, which can reach triple digits on a single day. Unfortunately, [[LightIsNotGood Light]] ''is'' [[VillainProtagonist Kira]].
** It's played with, in that L, [[BigGood the leader of the task force]], is never in any doubt that Light is Kira - inviting him to join the task force is just a ploy to attempt to prove his guilt. [[spoiler: It works. Eventually. Not that L's around to see it.]]
* In ''Anime/DigimonUniverseAppMonsters'', the Applidrivers gain a SixthRanger in the form of [[spoiler: Yuujin Oozora, Haru's best friend, and his Buddy Appmon Offmon]] mid-series. Rei finds the new addition to the team too eager to help and friendly, but the other Applidrivers and their Buddy Appmon see this as a bonus and welcome their new teammates with open arms. In the climax of the series, the horrible truth is revealed: [[spoiler: Yuujin is actually YJ-14, an ArtificialHuman created by [[BigBad Leviathan]] to [[DeepCoverAgent keep tabs on Haru and collect data on humans by living among them]]. Even his own Buddy Appmon didn't know this!]] This is obviously devastating to the Applidrivers, especially Haru. [[spoiler: However, being Haru's friend for half a decade made Yuujin grow a heart and personality of his own, so Leviathan has to take total control of his body to make him fight against his loved ones. When he regains control of his body, Yuujin is heartbroken over Leviathan's actions, and ends up making the choice to [[HeroicSacrifice delete Leviathan at the cost of his own life]], partially to prevent Haru from making that awful choice himself and living with having killed his best friend for the rest of his life.]]
%%* ''Manga/FushigiYuugi'''s Chiriko was really a Seiryu Seishi named Amiboshii.
* [[spoiler:Genpou Saji]] from ''Manga/IkkiTousen'' starts like this, manipulating both Rakuyou and Nanyou as TheManBehindTheMan. [[spoiler: [[DefeatMeansFriendship After being defeated, though, he becomes a genuine]] SixthRanger.]] In the anime, at least. The manga's a bit more involved, but [[spoiler:Saji]] was never evil.
%%* Team Trinity in ''Anime/MobileSuitGundam00'' season 1. [[spoiler: Anew Returner ([[ManchurianAgent unwillingly]])]] fills the role in season 2.
* Kaworu from ''Anime/NeonGenesisEvangelion'', although there's enough visual and in-plots hints about people wondering about him that he was deliberately a mysterious character. His character showed up in one episode, which means the time from Introduction to TheReveal about [[spoiler:his identity as The Last Angel]] was about ''fifteen minutes''. Subsequent versions of the story reveal it even faster, likely because [[ItWasHisSled almost anyone watching a remake will know it anyway]]. ''Death & Rebirth'' reveals Kaworu's betrayal before introducing him! The fact that he's first seen in ''Anime/RebuildOfEvangelion'' hanging out with Keel Lorenz is a pretty big indication by itself that he's not on NERV's side in the latest iteration of the story, either. [[note]]there is subversion in that He's not with SEELE or even the Angels, either in the end. He picks to side with the Lilim, and decides to at least buy some time for Shinji to survive. Not much good that did anyway, but it's the thought that counted.[[/note]]
** There's also EVA-03 and its pilot; however, the case of their betrayal was unintentional, as an Angel managed to hijack them before they even made a sortie.
* [[spoiler:Meowth of Team Rocket]] pretends to become a new ally for the heroes of ''Anime/{{Pokemon}} Best Wishes'' for one short StoryArc, but it was just to lure them into a trap in Nimbasa City.
* In the second season opening of ''Anime/ScienceNinjaTeamGatchaman'', the team gets a new G-2 as a replacement for dead [[TheLancer Lancer]] "Condor Joe" Asakura, much to the others' discomfiture. Surprise! He's a Galactor agent. Double surprise! [[spoiler: Joe, BackFromTheDead, kills him.]]
* Crona from ''Manga/SoulEater'' is taken in after turning good, then is manipulated back to Medusa to be TheMole
** In the anime, [[spoiler:Crona decides to stop working for Medusa]] and leave the DWMA out of guilt. Maka catches them on the way out and convinces [[spoiler:Crona]] to stay and be their ally for the rest of the show.
** In the manga, [[spoiler:Crona disappears just after being discovered]], having been called back by Medusa to her lair. Eventually, [[spoiler:Crona kills Medusa, but thought so lowly of themself for it that Crona decides to become a Kishin as Medusa planned]] and cause TheEndOfTheWorldAsWeKnowIt. Maka manages to talk [[spoiler: Crona]] back, but by that point [[spoiler: Crona]] had done so much wrong they ended up being a BarrierMaiden for the rest of their immortal life as repentance, or until Maka manages to rescue them, depending on your personal interpretation.
* Played with in ''Anime/SwordArtOnline'': [[spoiler:After losing in a duel to Heathcliff, Kirito]] is forced to join the Knights of the Blood. After a costly boss raid with [=KoB=], [[spoiler: Kirito realizes Heathcliff is actually Akihiko Kayaba, creator of SAO]] and the one responsible for trapping all the players in the game. His ruse exposed, [[spoiler: Kayaba reveals that he was setting himself up to betray the [=KoB=] and set himself up as the game's FinalBoss]].

[[folder:Comic Books]]
* ComicBook/TheAvengers: The Swordsman, a VillainWithGoodPublicity, joined ComicBook/TheAvengers under orders from ComicBook/IronMan's enemy the Mandarin to sabotage the team. After gaining the trust of most of the team, he planted a bomb in their headquarters. It was after he had [[HeelFaceTurn a change of heart]] and disarms the bomb that he was found out and [[ReformedButRejected the team sent him packing]].
* Nemesis Kid of the Legion in ''Comicbook/LegionOfSuperHeroes''. He joined the Legion to spy on them for the evil Khund Empire (and later became a member of the Legion of Super-Villains).
* Shun-Day was this to the [[ComicBook/LesLegendaires Legendaries]], acting as TheMole to her creator [[EvilSorcerer Skroa]]. She however [[BecomingTheMask become the mask]] and ends up saving the other Legendaries from him. [[TheHero Danael]] agreed to let her go as a gratitude, but warned her that the next time they'd meet, it'd be as enemies.
** Later subverted during the Anathos Cycle when Tenebris, [[DaddysLittleVillain Darkhell's daughter]], joins the team. Her motivations for helping the heroes are selfish, she is known to love her father, and two of the Legendaries (namely Shimy and Gryf) were expecting her to betray them, to the point Shimy tried to [[MurderIsTheBestSolution murder]] her once it appeared she was of no more use. Ironically, it turned out she ''never'' betrayed the team, even when Anathos [[WeCanRuleTogether gave her the opportunity to join her]] [[CurbStompBattle after he single-handedly defeated the other heroes]]. After the Cycle, she has become a full-time member of the group.
* ''Comicbook/{{Runaways}}'':
** Topher is introduced as a kid apparently in a similar position to the heroes, and is a little too charming and eager to get on with everyone. He turns out to be a vampire and tries to murder them all. His betrayal causes the team to be initially suspicious of SixthRanger Victor Mancha, especially since they know he's [[LukeIAmYourFather the son of a villain]] (though they don't know which one for a while) and supposedly destined to [[FaceHeelTurn turn evil]]. Given that every single fricken one of them is the child of at least one, and in most cases two villains, what do ya expect?
** It's also implied to have happened on purpose, because [[spoiler:Alex]] knew all along that Topher was a vampire (or at least evil) and brought him to the Hostel so that the rest of the group could end up fighting him to be toughened up.
* ''ComicBook/StarWarsMarvel1977'' does have regulars added to the cast not infrequently. Most of them work out okay - but [[HeroesWantRedheads Shira Brie]], Luke Skywalker's [[{{Wingman}} Wing Guard]] and incipient {{Love Interest|s}}, turns out to have been hand-picked by Darth Vader.
* ComicBook/TeenTitans: After the [[Comicbook/TeenTitans New Teen Titans]] formed, their first new member was Terra, a cute teen girl with a sad backstory. One year later...well, there's a reason that Terra's grand finale is called ''Comicbook/TheJudasContract''. (However, the Titans didn't return to status quo; ''The Judas Contract'' also introduced Jericho, who became a long-standing member of the team.)
* Titan's ''WesternAnimation/TransformersAnimated'' Comic had a new character called Afterburn, who is [[ParodySue one of the greatest Autobots to ever live, who cured a fatal infection and has recommendations from Ultra Magnus himself]]. [[spoiler: He's really a soulless drone created by Megatron, who faked his credentials.]]
* In an example that would have made fans of the original series cry, [[spoiler:Sven]], one of the most popular characters of the original ''[[Anime/{{Voltron}} Voltron: Defender of the Universe]]'' series became this in the 2003-4 Devil's Due DarkerAndEdgier ContinuityReboot.
* ComicBook/WonderMan, the first [[ComicBook/TheAvengers Avenger]] to join the team after ComicBook/CaptainAmerica, was one of these. An industrialist driven out of business by [[ComicBook/IronMan Tony Stark]], he was approached by the [[Characters/MastersOfEvilFoundingMembers Masters of Evil]] and offered superpowers and revenge. It wasn't until after he'd gotten his [[SuperStrength powers]] that the Masters revealed the catch -that his powers would kill him without regular treatments that only ComicBook/BaronZemo could provide - and sent him to infiltrate the Avengers. Since GoodFeelsGood, though, Wonder Man discovered he preferred being a hero and ended up saving the team from the Masters' trap at the cost of [[RedemptionEqualsDeath his own life]]. (Being comics, he got better. Then worse. [[DeathIsCheap Then better again]].)
* In Creator/GrantMorrison's run on ''Comicbook/XMen'', where the core team starts out as a FiveManBand, Xorn [[spoiler:isn't just a traitor, he's [[Characters/MarvelComicsMagneto Magneto]] in disguise]]! ([[TheRealRemingtonSteele For a while, anyhow.]]) Change and (perhaps futile) attempts to escape the status quo were major themes in this run. The first to join the ''original'' FiveManBand (not counting the Professor) from the sixties, Mimic, ''also'' betrayed the team.
** ''ComicBook/NewXMenAcademyX'' has an interesting case with this happening to both the New Mutants and their rival team at the same time. Both teams were five groups of friends short of one to make a full training squad. Icarus was added to the Hellions, whom he barely knew, because Julian convinced him to join, and Wither joined the New Mutants after he returned to school. Once the FBI tried to arrest Wither, the Hellions decided to bust him out and Icarus, realizing how horrible the consequences such act would have, contacted the New Mutants and both groups fought. Once Wither was cleared of all charges he realized who his real friends were and asked to be re-assigned to the Hellions, while Icarus jumped at the opportunity to take his spot on the New Mutants.

[[folder:Fan Works]]
%%* In ''Fanfic/PersonalityConflicts'', this is Tommy's greatest fear. Also played straight with Drew and BadFuture Tasha, but subverted with Ryan.
* In ''Fanfic/SeventyTwoHours'', Bo is this to the wrestlers. When he moves to America, he falls in naturally with the sadistic group, but has no interest in slaughtering innocents with the others; he simply can't escape. During a battle with [[LaResistance SABRE]], he not only joins the enemy (pulling a complete HeelFaceTurn in the process) but does so in a way that cripples the enemy attack, saving his new friends' lives.
* Miyako in ''Manga/DeathNote'' and ''Manga/PhantomThiefJeanne'' fanfic, ''Fanfic/ToKillAThief'' is unknowingly helping Light. [[spoiler:When she realized of what he wanted, she turns her back on him.]]
%%* [[spoiler: Zeakros]] in ''Fanfic/AceCombatTheEquestrianWar''.
* The [[BadFuture Dark World]] arc of the ''FanFic/PonyPOVSeries'', [[spoiler: Discord's sister Rancor joins him and his minions in fighting the Elements of Harmony's rebellion... only to stab him InTheBack (literally) at the opportune moment, in order to steal Destruction's power for herself]].
* In [[https://www.fanfiction.net/s/6310457/1/Devil-s-Advocate "Devil's Advocate"]] [[Anime/DigimonTamers Takato]] joins the [[Anime/DigimonAdventure02 Digidestined]] to help them defeat the Digimon Emperor. However, as soon as the Emperor dies, Takato plans to [[YouHaveOutlivedYourUsefulness turn on the others and kill them.]]
* ''Fanfic/ADiplomaticVisit'': The epilogue of the fourth story, ''The Diplomat's Life'', reveals that [[spoiler:Lady Aputsiaq]] is secretly working for the same being who was served by [[spoiler: Subtle Dancer from [[Fanfic/EscapeFromTheMoon the Doa-verse]]]], and stole the Gem of Sacanas from where Twilight had it stored and turned it over to them. Twilight herself remains unaware of the thief's identity.
* ''Fanfic/CindersAndAshesTheChroniclesOfKamenRiderDante'' introduces Shimashima, a producer who once worked with [[PosthumousCharacter Setsuna]] and is now working with the main heroes to stop her final creation, Altair, from destroying the multiverse. However, midway through the story, it is revealed that Shimashima was merely a cover for his true identity: Yuusuke Shimazaki, Setsuna's father, and that his true allegience is with Altair.

[[folder:Films -- Live-Action]]
* ''Film/{{The Avengers|2012}}:'' Hawkeye, an archer, the sixth member of the Avengers, who had no speaking lines prior to this film, is mind-controlled by [[BigBad Loki]] and fights for him until the third act of the movie. Hawkeye is particularly dangerous because of his knowledge of SHIELD protocols and weaponry, particularly the weak points thereof.
* ''Film/DogSoldiers'' - [[spoiler: Megan]], who was a werewolf in secret from the start and believed the squad could somehow save her, betrays the soldiers after coming to the conclusion that either they weren't there to help her and that they'd kill her if they found out her secret, or that their chances of surviving the night were nil, or a combination of both.
* ''Film/{{Eternals}}'': The Eternals consider one another family. However, [[spoiler: Ikaris]] is so troubled by the idea of saving Earth from [[PlanetDestroyer the birth of a Celestial]] that he kills [[spoiler: their leader, Ajak]], in hopes of replacing her, which would allow him to keep the plan from the rest of the group and ensure all goes according to their original orders. When that fails, he attempts to kill any member of the group who works against the Celestial's emergence. It proves a difficult fight as [[spoiler: Ikaris]] was their Second-In-Command and knows them quite well. He is also aided by [[spoiler: [[TheBabyOfTheBunch Sprite]]]] who has Loki-like powers of illusion and misdirection.
* In ''Film/TheFaculty'', [[spoiler:Marybeth]] is this in a meta sense. While the other five protagonists didn't know each other before the events of the movie, they ''are'' pretty obviously based on the group from ''Film/TheBreakfastClub'' ([[JerkJock Stan]]'s counterpart is Andy, [[AlphaBitch Delilah]]'s is Claire, Casey's is Brian, [[{{Delinquents}} Zeke]]'s is Bender, and [[MisunderstoodLonerWithAHeartOfGold Stokely]]'s is Allison), leaving one to wonder where [[spoiler: Marybeth]] fits in. The answer: she doesn't. She's the [[spoiler: [[HiveQueen queen alien]] leading the {{Puppeteer Parasite}}s that are taking over the school]].
* In ''Film/GraveEncounters2'' [[spoiler: Lance]] appears out of nowhere, having apparently survived [[spoiler: the first movie]] and shows up to aid the remaining survivors. Too bad for them he is taking orders from the hospital itself which speaks by scratching words into the walls or following him around invisible in the darkness of the hospital. To make this even worse, he [[spoiler: kills Trevor]] and attempts to escape the hospital himself. [[spoiler: too bad the demons of the hospital double crossed him too.]]
%%* ''Film/TheLosers'' - [[spoiler: Roque]].
%%* ''Film/TheExpendables'' - [[spoiler: Gunnar. [[EasilyForgiven They let it slide]] before the [[Film/TheExpendables2 sequel]]]].
%%* ''Film/SuckerPunch'': [[spoiler: Blondie]].
%%* ''Film/TransformersDarkOfTheMoon'': [[spoiler: Sentinel Prime]].
%%* ''Film/TheItalianJob2003'' - [[spoiler: Steve]].
* In ''Film/Seven1979'', Mailei reveals herself to TheMole inside TheSyndicate: providing to information to Harris and the feds on their plans to take over Hawaii, and then sent to help the Seven to stop them. However, she later turns out to be a double agent, providing TheSyndicate with information about how much the feds know, and tries to kill Cowboy.
* ''Film/XMenFirstClass'': The Mutants are initially happy simply to have found others like them, but the group eventually splits over fundamental differences in ideology.
** After a fun evening spent demonstrating their powers, [[spoiler: Angel]] abandons the team after their CIA safehouse is attacked, agreeing with Shaw that Mutants should not have to fear the humans.
** After the combined US and Cuban militaries attempt to kill the Mutant squad that has just kept the two countries from initiating what promised to be a costly and destructive war, [[spoiler: Magneto and Raven]] decide it's dangerously naive to continue to work with the CIA-backed team. [[spoiler:Magneto]] will go on to use the leadership skills he learned from Charles and the increased abilities Charles helped him hone to establish the ''Characters/XMenBrotherhoodOfMutants'' which will frequently clash with the X-Men.
%%* Lando Calrissian acts as this at in ''Film/TheEmpireStrikesBack'' but he quickly makes a HeelFaceTurn and becomes a regular SixthRanger.
%%* In ''Film/TheHungerGames'', [[spoiler:Peeta Mellark]] is this to the Career Tributes like the novels below.

[[folder:Literature]]
%%* ''Literature/LorienLegacies'' has also got this trope, except it's a '''[[spoiler:[[{{Pun}} Fifth]]]]''' ranger traitor.
%%* ''Literature/{{Dragonlance}}'' - [[spoiler:Eben Shatterstone]].
* ''Literature/{{Animorphs}}'': [[spoiler:David]]. Note that no one really wanted him to join, and he didn't either, but [[spoiler:he'd found the morphing cube and his parents had been taken by Yeerks, while the Animorphs barely rescued him from being taken as well.]] While he doesn't side with the Yeerks, his goal being becoming rich with an army of morph-capable minions, he runs the team ragged by demonstrating how difficult it is to track and fight someone with their powers. He ends up [[spoiler:permanently [[ShapeshifterModeLock trapped]] in rat morph]], and his fate [[spoiler:(a MercyKill by Rachel or left to live as a rat)]] is left deliberately vague.
* Senna from ''Literature/{{Everworld}}'' is sort of an odd example--she technically put together the group, but keeps flitting in and out of it herself (until book #7, when she stays with them until her final betrayal). She's definitely a TokenEvilTeammate, though, and after a while doesn't even try to conceal the fact that she's manipulating them, though she keeps her exact plans hidden. Unfortunately, the others have to put up with her, since she's MacGuffinSuperPerson and the only one who can bring them home.
%%* Franchise/StarWarsExpandedUniverse:
%%** [[spoiler:Jacen]], though it's fairly obvious before he actually becomes a Sith.
%%** Kyp in the ''Literature/JediAcademyTrilogy''.
%%** In the Coruscant Nights Trilogy, [[spoiler: Dejah Duare]].
* In ''Literature/HarryPotter'': [[spoiler:Severus Snape]] is actually a Sixth Ranger Traitor for the villains, earning himself a (sudden) special place in the hearts of many readers who had previously hated his guts.
%%* In ''Literature/TheHungerGames'', [[spoiler:Peeta Mellark]] is this to the Career Tributes.
* In ''[[Literature/TheInfernalDevices The Clockwork Prince]]'', [[spoiler:Jessamine Lovelace]] betrays the Institute [[spoiler:because of her love for Nate]].
* ''Literature/VillainsByNecessity'': Robin, the last and sixth member of the party to join, is a spy from Mizzamir. However, he isn't really evil, and switches sides after learning their quest is right.

[[folder:Live-Action TV]]
* ''Series/BuffyTheVampireSlayer'':
** In season 3, Faith is introduced as a second Slayer and hedonistic ShadowArchetype to Buffy. It takes a few episodes, but a fatal accident sets her on a spiral into a FaceHeelTurn. She eventually makes a HeelFaceTurn and goes back to being one of Buffy's most important allies, though.
** Rather amusingly, Spike (who now has a RestrainingBolt to keep him from killing people) plays the SixthRangerTraitor role in season 4 -- selling out Buffy and the Scoobies to [[UltimateLifeform Adam]] -- despite the fact that he makes no bones about being evil and hating the Scoobies the whole time.
--->'''Spike''': Tell you what I'll do then. I'll head out, find this girl, tell her exactly where all of you are, and then watch as she kills you.
--->''*shocked silence from Xander and Giles*''
--->'''Spike''': Can't any one of your damn little Scooby club at least ''try'' to remember that ''I hate you all''? Just because I can't do the damage myself doesn't stop me from aiming a loose cannon your way. And here I thought the evening'd be dull.
* Oddly enough, the reality show ''Dance Moms'' has an example of this, when [[spoiler:the newest mother to the group, Cathy]], defects back to her own dance studio, then decides to directly compete against her erstwhile colleagues in an upcoming competition. She even specifically states that now she's seen the Abbey Lee company from the inside, so she can use their own methods against them, going so far as to steal one of the children's music. Like most Sixth Ranger Traitors, she fails spectacularly.
* [[spoiler: Zoey]] from ''Series/HowIMetYourMother'' became one of these, after she grew very close with the gang and even dated Ted. However when [[spoiler: Ted said "no" to preserving an old building called the Arcadian]], said person revealed to have [[spoiler: kept the recording she made of Ted praising the Arcadian]] despite having promised to get rid of it.
* [[spoiler: Chester Lake]] from ''Series/LawAndOrderSpecialVictimsUnit'' eventually ends up killing a rapist cop who was found not guilty at trial. To [[spoiler: Lake]]'s credit, said cop had previously tried repeatedly to kill him, and in the end he made no attempt to conceal his crime. Much more fitting to the trope is TheScrappy [[spoiler: Dale Stuckey]], who turns out to have masterminded a plot to kill the lawyers and judge in a serial killer's murder trial in order to frame the killer, who he had originally accidentally set free due to screwing up the forensic evidence. He ends up killing the MauveShirt CSI tech, and almost ends up killing Stabler.
%%* [[spoiler: Leek]] from ''Series/{{Primeval}}''. And Christine. And Philip. If the team (or Nick in series 2, and Abby in series 5) hate somebody, then that person is, guaranteed, to be evil!
* Rick Murray from ''Series/DegrassiTheNextGeneration''. Crazy, check. Ready to explode, check. Attacks his friends, check.
%%* Jorge del Salto from ''Series/{{Carrusel}}''.
* ''Series/{{NCIS}}'' had both [[spoiler: Chip]], who inserted himself into [=NCIS=] as part of a long term scheme to get revenge on Tony for ruining his career years ago, and [[spoiler: Agent Lee]], who was an enemy double agent. For a while the team took it for granted that Ziva was one of these, being a double agent for the Israelis, but she eventually proves her loyalty to the team.
* ''Franchise/PowerRangers'' and ''Franchise/SuperSentai'':
** Zhane in ''Series/PowerRangersInSpace'' actually disguised himself as a "Sixth Psycho Ranger" in order to confuse ThePsychoRangers.
** To the point, despite the trope name, this really hasn't happened in ''Franchise/PowerRangers''. Sixth Rangers have started as antagonists and even villains, but it's always been due to mind control or the manipulation of the truth. The closest examples would be ''Series/PowerRangersNinjaSteel'', where Brady's brother Aiden [[spoiler: turns out to be ActuallyADoombot sent by TheStarscream]], and the ''[[ComicBook/MightyMorphinPowerRangersBoomStudios Mighty Morphin' Power Rangers]]'' comic which introduced an actual "Sixth Psycho Ranger" called Psycho Green who is later revealed in the Year Two Deluxe Edition to be [[spoiler:the former Sixth Ranger of the [[Series/ChikyuuSentaiFiveman Supersonic Rangers]] of [[Series/PowerRangersTimeForce Xybria]] who, after being benched too many times by his leader, lured the core FiveManBand into a trap and killed them all. An act of betrayal that won over the favor of Dark Specter]].
** One of the few examples of this happened in ''Series/ChoudenshiBioman'' in a two part story where a man tries to join the team and fights beside them but gets rejected when the test for bio particles comes back negative. The villains take advantage of him by tricking him into letting them turn him into an evil ranger whose suit is powered by magne metal instead. Unlike future sixths rangers he does not keep his powers after he is freed.
** ''Series/ShurikenSentaiNinninger'' had a green ranger join the team in one of the movies only for her to be revealed to be possessed by a villain.
* ''Series/{{Revenge}}'': If you go by AlternativeCharacterInterpretation, Ashley Davenport, although she also isn't fully aware of her role in Emily's scheming and is at least partially loyal to the Graysons.
* The ''Series/{{Torchwood}}'' episode "Adam" had the eponymous mind-altering alien acting as the team's most trusted member. [[DramaticIrony The viewers know he's the bad guy all along]].

[[folder:Myths & Religion]]
%%* Judas Iscariot, the UrExample.
* Hushai plays the role of TheMole for King David in the story of Absalom's rebellion. The guy even has the balls to lampshade it ''in front of Absalom''.
%%* Mordred in Myth/ArthurianLegend.
[[/folder]]

[[folder:Pro Wrestling]]
* Wrestling/CMPunk played the good version of this in Wrestling/{{WWE}}'s {{Wrestling/ECW}} revival, infiltrating [[PowerStable the New Breed]] in order to break them apart from within.
* Wrestling/{{EVIL|Wrestler}} played the... well, evil version of this in [[Wrestling/NewJapanProWrestling NJPW]], betraying Wrestling/LosIngobernablesDeJapon and joining Wrestling/BulletClub in 2020. LIJ had been a full-blown heel stable when he joined, but had transitioned to being tweeners by the time he left.
* Wrestling/{{MJF}} played the evil version ''twice'' in [[Wrestling/AllEliteWrestling AEW]]:
** In late 2019, he allied himself with Wrestling/CodyRhodes and his Nightmare Family, seemingly turning face, but betrayed Cody a few weeks later, cementing himself as a heel.
** A year later, he joined AEW's top heel stable, the Wrestling/InnerCircle, but manipulated them for months, driving original member Sammy Guevara from the stable and attempting to usurp Wrestling/ChrisJericho as leader. Jericho then booted MJF from the stable in March 2021, only to find that MJF [[StartMyOwn started his own heel stable]]. MJF's group, soon unveiled as The Pinnacle, beat the Inner Circle down, effectively turning the latter face.
[[/folder]]

[[folder:Video Games]]
* Khunag of ''VideoGame/{{Albion}}'' joins the party as the sixth ranger. He has little role for awhile. Then at one point, the player must infiltrate the cult he once belonged to, and he's the only guide available. He 'guides' the player into declaring war on the cult, slaughtering their best warriors and eventually killing the leader, with whom he had a score to settle.
* In ''[[AlternateUniverse Another Day]]'', the bonus chapter of ''VideoGame/TheWorldEndsWithYou'', [[spoiler:Rhyme]], of all people [[note]]this is the insanity that is ''Another Day''[[/note]] pulls this on Neku...er, Shuto's [[FiveManBand team]] of Tin Pin Slammer-playing heroes.
** Subverted in ''VideoGame/NEOTheWorldEndsWithYou'' with [[spoiler:Shoka]]. Originally joining the Wicked Twisters as a mole to spy on them for the Reapers' benefit, she felt incredibly guilty betraying her now teammates who considered her a friend. She ends up fully defecting from the Reapers and permanently joining the Wicked Twisters as a proper SixthRanger.
* In ''[[VideoGame/BaldursGateII Baldur's Gate II: Shadows of Amn]]'', your starting party consists of entirely of characters from the first game... and Yoshimo. Guess who betrays you?
* [[spoiler:Onef]] of ''VideoGame/TheBannerSaga''. Is recruited from [[spoiler:Frostvellr]], and fills out this role in the party. Invariably turns on the party later on, as [[{{Foreshadowing}} pointed out]] by their class title [[spoiler:"Backbiter"]]. Ends up killing a good number of your clansmen along with [[spoiler:Egil]], and [[spoiler:Oddleif]] comes scarily close to dying as well.
* Harle in ''VideoGame/ChronoCross'', twice, betraying Lynx for you because [[spoiler:you are Lynx]] and then betraying you for [[spoiler:the Dragons]] after you beat FATE.
* ''Franchise/FinalFantasy'' series
** In ''VideoGame/FinalFantasyIV'', when returning to Baron, you run into Cecil's old friend Chancellor Baigan. He "joins" your party (despite the fact that your party is already full; the game doesn't ''allow'' six playable characters to be used at once) and he follows along behind you (unlike all the other party members who aren't shown on screen during normal gameplay). He is revealed as a monster in disguise about five seconds later. In the DS remake, this is played as a cutscene and Baigan has a new 3D model, and he immediately reveals himself as a monster in the cutscene.
** ''VideoGame/FinalFantasyX'' - [[spoiler:Maester Seymour]], since he joins the party briefly before turning out to be an OmnicidalManiac.
** ''VideoGame/FinalFantasyXII'' offers one for both sides: The heroes get [[spoiler: Vossler]], and the villains get [[spoiler: Gabranth]].
** ''VideoGame/FinalFantasyTactics'' gives us Algus/Argath, the guest for about half of Chapter 1. Also Gafgarion, a guest for several battles during Chapter 2.
** ''VideoGame/FinalFantasyTacticsA2'' gives us [[spoiler:Adelle, though she's merely BrainwashedAndCrazy]].
* Played with in ''VideoGame/FireEmblemFates''. The Avatar unintentionally becomes one in the ''Conquest'' version of the game when they return to their adopted family in Nohr after being reunited with and fighting alongside their biological one in Hoshido for a while.
* Aydana Kozlova in ''[[VideoGame/GhostRecon Ghost Recon: Shadow Wars]]'' is a subversion of this trope. [[spoiler: She seemed to betray the team and released the enemy that TheSquad had just captured. It turns out that she only released him so the team would be able to track him down and lead them to the BigBad. Then she rejoined your team and was EasilyForgiven.]]
* ''VideoGame/GrimFandango'': Shortly after joining the LSA, [[spoiler:Olivia betrays Manny and the rest of the group for her new boyfriend, [[BigBad Hector LeMans]].]]
* Dark Pit from ''VideoGame/KidIcarusUprising'' was created by Pandora to be an EvilKnockoff of [[TheHero Pit]] who'll fight for the Underworld Army. 10 seconds after his creation, he defects and becomes a neutral WildCard during most of the game [[spoiler: until he joins with Pit near the end of the game]].
** This is all due to Dark Pit being Pit's opposite. But rather than morality, Pit's core virtue is his loyalty.
* ''VideoGame/MassEffect3'': [[spoiler: Maya Brooks]] in the "Citadel" DLC. She pretends to be a low level, bumbling but well-intentioned Staff Analyst, helping to uncover the assassin who is attempting to kill Shepard by providing the team with dossiers, information, and advice. In actuality, she is behind the attempt, intending to kill Shepard and replace them with a clone that will allow her to use Shepard's connections and reputation to push her Human Supremacist agenda on the galaxy.
%%* This is how [[spoiler: Bass]] was introduced in ''VideoGame/MegaMan7''.
%%* ''VideoGame/MegaManX4'' - [[spoiler:Double. Not that that is a MeaningfulName or anything]].
* ''[[VideoGame/{{Onmyoji}} Onmyōji]]'': [[spoiler: Yaobikuni, who suddenly turns on her friends and reveals her motives after being taken to [[BigBad Kuro Seimei]]'s place. [[Headscratchers/{{Onmyoji}} She is still a playable character after this revelation]]]].
* [[spoiler:Goro Akechi]] in ''VideoGame/Persona5''. Subverted in that [[spoiler:the gang already knew he was TheMole from the start and actually finds a way to counter his plan (to kill Joker and have the Phantom Thieves arrested) with a very clever BatmanGambit. He later joins the party for real in the ''Royal'' UpdatedRerelease. There's also Yoshizawa, who briefly turns on the party during a HeroicBSOD before coming to her senses]].
* ''VideoGame/PhantasyStarIV'' has "Seth" who you meet at the entrance of a dungeon. [[spoiler:At the end of said dungeon, he turns out to be the third incarnation of Dark Force that you fight in the game.]]
* At the end of ''VideoGame/PlanescapeTorment'', [[spoiler:depending on your [[KarmaMeter alignment]] either the TokenEvilTeammate Ignus or the [[BlackAndWhiteInsanity insane]] SixthRanger Vhailor will turn on you at the behest of the BigBad in the final dungeon]].
* [[TheDragon Courtney Gears]] in ''VideoGame/RatchetAndClankUpYourArsenal''. At first, it looks like she agrees to assist the Q-Force in helping out with their battle against [[BigBad Dr. Nefarious]], but soon [[FaceHeelTurn betrays the team]] [[spoiler:by kidnapping Clank and using Skidd as a test subject for the Biobliterator in her lair, the Obani Draco]]. She soon [[DisneyVillainDeath meets her end]] at the hands of Ratchet, but is [[DeathIsCheap later restored]].
** [[VideoGame/RatchetAndClankFutureToolsOfDestruction Rusty Pete]] may also count, since he only allys himself with Ratchet to [[spoiler: find the body of Angstrom Darkwater so that he can revive Captain Slag]].
* ''VideoGame/SaintsRow2022'' has the Nahualli, who is the StarterVillain in the first mission, then later gets broken out of prison in order to have him help the Saints out on a TrainJob. He's integrated into the gang, tagging along on a team-building activity day, and seems to have become a loyal new member of the Saints, but [[spoiler:at the game's climax, he betrays the Boss [[IJustWantToHaveFriends out of jealousy for their friendship with Neenah, Kevin, and Eli]] and ends up becoming the FinalBoss of the game]].
* Penelope in ''VideoGame/Sly3HonorAmongThieves'' is technically the second recruit, and therefore the fifth ranger, but the way she joins is different from the Guru, Panda King, and Dimitri; they all join out of gratitude for the Cooper Gang's help with their own problems, while Penelope joined to keep her promise to Bentley. ''Nobody'' knew she had a [[AmbitionIsEvil very selfish motivation]] for joining until [[MoralEventHorizon it was too late]], and she betrayed the gang to Le Paradox in ''VideoGame/SlyCooperThievesInTime'' in order to harvest [[MealTicket Bentley's]] "potential" and TakeOverTheWorld.
* Applicable to two different character routes in ''VideoGame/StarWarsTheOldRepublic''.
** The Republic Trooper story inverts the trope, casting the player character as the newest member but [[spoiler: being the only one squad member to remain loyal after everyone else defects to the Empire.]]
** The Imperial Agent story plays this straight and has this happen twice over; the player character themselves serves as [[spoiler: one for a team of Republic spies, acting as a double-agent to get info - only for ''another'' member of the team to be a double-agent themselves]], except that they serve a [[spoiler: [[GreaterScopeVillain third group]] who is inflaming the war for their own ends.]]
* The only playable character in ''VideoGame/TalesOfXillia2'' not previously established from [[VideoGame/TalesOfXillia the first game]] is the protagonist Ludger Kresnik, who [[spoiler:in the Bad Ending kills the rest of the party in order to stop them from sacrificing his brother.]]
* ''VideoGame/UltimaV'' has [[SdrawkcabName Saduj]] who can join your party, but it turns out he's a spy for the BigBad, not just that but he'll flee every battle you enter massively dropping your karma eventually making the game unwinnable. Really the only use for him (Without him having to join) is that he's the only clue to the existence of the Sandalwood Box that is one of many items you need to beat the game, and that you can make him a [[UriahGambit Hairu]] in a particular battle.
[[/folder]]

[[folder:Web Comics]]
* ''Webcomic/TheCrossoverlord'': [[spoiler:The Green Avenger]] was this. Justified, because she was [[spoiler: brainwashed by Smiling Man]].
* Eikre from ''Webcomic/RPGWorld'' was heavily implied to be one of these when he joined the party. [[spoiler:Subverted when it turns out he was [[RedHerringMole on the level]] and the real [[TheMole mole]] was a flower that he bought from a random NPC to give to Cherry.]]
* [[spoiler:[[SquishyWizard Emily]] ]]from ''Webcomic/OurLittleAdventure'' turned out to be a PuppeteerParasite ManchurianAgent of the [[TheEmpire Souballo Empire]].
[[/folder]]

[[folder:Web Videos]]
* In the ''WebVideo/YogscastMinecraftSeries'', specifically ''[=MarsQuest=]'' [[spoiler:LetsPlay/{{Sjin}}]] joins up with LetsPlay/LewisBrindley, LetsPlay/SimonLane and LetsPlay/DuncanJones to get to Mars and rescue the captive [[spoiler:LetsPlay/{{Sips}}]]. Once the goal is achieved, he tries backstabbing Team J.A.F.F.A, but this fails ''horribly''.
[[/folder]]

[[folder:Western Animation]]
* ''WesternAnimation/ChipNDaleRescueRangers'':
** Foxglove helped the Rangers mainly so she could steal the episode's {{Plot Coupon}}s they found, and give them to the villain/goons she worked for... and also because of an affection for Dale, which lead to her HeelFaceTurn back to the Rangers.
** Desiree D'Allure, Monterey Jack's old crush, does this as well... except unlike Foxglove, she ''stays'' evil, and gets away with it! (Well, not completely.)
* William from ''WesternAnimation/CodeLyoko'' joins the team in the second-to-last episode of the third season, even though he was already considered 7 episodes ago. Although he is not evil and never becomes evil, his inexperience and cockiness combined with some errors from the heroes themselves led to XANA taking him over in the following episode. The surprise factor was actually legitimate, because the build-up was so long.
* In ''WesternAnimation/GIJoeSigma6'', [[spoiler:Firefly]] ends up betraying the team to Cobra.
* In the second season of ''WesternAnimation/TheLegendOfKorra'' [[spoiler: Varrick]] is this for a while to the Krew. Even when he begins manipulating and betraying some of the members, it takes them a while to figure it out. Even after he's exposed, he still thinks they're friends. [[spoiler:He does eventually do a HeelFaceTurn a good two books later, but he had to earn everyone's trust and forgiveness again because of said betrayal.]]
* Discord pulls this stunt in the Season 4 Finale of ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' after listening to Tirek's HannibalLecture. Getting swiftly backstabbed, [[ManaDrain drained of his powers]], and ''still'' forgiven by his former friends kicks him back to the pony's side for good... [[HeelFaceRevolvingDoor probably]]… [[ReformedButNotTamed hopefully]].
* Terra from ''WesternAnimation/TeenTitans''. Unlike in the comics, where Terra was EvilAllAlong, Terra started as an ally, rejected membership over a misunderstanding, and had become TheMole by the time she took it up. If it wasn't obvious enough that Terra as a Titan wasn't going to last long, the episode following her joining the team has her suspiciously absent save a very brief non-speaking cameo in the end, and the title of the next episode when she actually appears as a member of the team? [[SpoilerTitle "Betrayal"]]
* In ''WesternAnimation/ThunderCats2011'', [[spoiler:Pumyra is actually a DeadAllAlong FemmeFatale who wants Lion-O dead for accidentally abandoning her to die in the rubble of Thundera]].
* [[spoiler: Longarm Prime]] from ''WesternAnimation/TransformersAnimated'' is introduced in a flashback as Bumblebee and Bulkhead's loyal classmate in boot camp, but the end of the episode reveals him to be Shockwave in disguise.
* In ''WesternAnimation/{{Robotix}},'' the Protectons eventually revive another of their [[SealedGoodInACan frozen comrades]] into a [[BrainUploading robot body,]] but unknown to them, Nemesis switched things so the body actually houses the mind of one of his minions, Venturak.
** All groups of 6 heroes have one of these. The [[PrecursorHero Pillars of Old Equestria]] has Stygian and the Young 6 have Cozy Glow. Stygian performed a HeelFaceTurn, while Cozy Glow... [[EnfantTerrible didn't.]]
* ''WesternAnimation/StarWarsTheCloneWars'': In the episodes Downfall of a Droid and Duel of the Droids, R2-D2 goes missing in battle. He is replaced by R3-S6, a bumbling droid who tries to do as commanded but can't seem to do anything. While Ahsoka gives R3-S6 the benefit of the doubt, believing the droid just needs time to master all the skills that R2-D2 was capable of, it's eventually revealed he is actually a [[TheMole malicious bot]] planted by General Grievous to spy on the Jedi and to actively thwart as many plans of action as possible.
* ''WesternAnimation/StevenUniverse'':
** In [[spoiler:"Bismuth"]], the [[spoiler:eponymous Gem]] joins the main group, and even shows up with the rest of the main cast in {{eyecatch}}es. While the character isn't a traitor, they do turn out to be a WellIntentionedExtremist who ends up fighting the main character Steven. [[spoiler:Ironically, Bismuth views Steven's mother as having betrayed ''her'', since Rose imprisoned her for crafting a weapon that can shatter gems... and failing to see the hypocrisy of turning Homeworld's most heinous tactic of intimidation against them.]] The character is re-imprisoned at the end of the episode. [[spoiler: Two seasons later, in "Made of Honor", she comes back and permanently rejoins the team with no violent intentions.]]
** Another episode sees "Navy", a member of the QuirkyMinibossSquad of Rubies, say she wants to join the Crystal Gems. Garnet is hesitant, but Steven gives her a chance and has the team's actual sixth rangers, Peridot and Lapis, show her the ropes. However, [[spoiler:Navy just wanted to take back her ship, which the Crystal Gems had previously commandeered and Peridot had been tinkering with. Once she, Steven, Peridot, and Lapis are on board, she takes off on a test flight, only to eject the heroes and escape.]]
[[/folder]]

* An episode of ''WesternAnimation/StevenUniverse'' pulls a twist on this trope. In [[spoiler:"Bismuth"]], the [[spoiler:eponymous Gem]] joins the main group, and even shows up with the rest of the main cast in {{eyecatch}}es. While the character isn't a traitor, they do turn out to be a WellIntentionedExtremist who ends up fighting the main character Steven. [[spoiler:Ironically, Bismuth views Steven's mother as having betrayed ''her'', since Rose imprisoned her for crafting a weapon that can shatter gems... and failing to see the hypocrisy of turning Homeworld's most heinous tactic of intimidation against them.]] The character is re-imprisoned at the end of the episode. [[spoiler: Two seasons later, in "Made of Honor", she comes back and permanently rejoins the team with no violent intentions.]]

* In Creator/GrantMorrison's run on ''Comicbook/XMen'', where the core team starts out as a FiveManBand, Xorn [[spoiler:isn't just a traitor, he's ComicBook/{{Magneto}} in disguise]]! ([[TheRealRemingtonSteele For a while, anyhow.]]) Change and (perhaps futile) attempts to escape the status quo were major themes in this run. The first to join the ''original'' FiveManBand (not counting the Professor) from the sixties, Mimic, ''also'' betrayed the team.

%%* Mordred in the Myth/KingArthur [[Myth/ArthurianLegend mythology]].

[[folder:Web Animation]]
* In the ''Machinima/YogscastMinecraftSeries'', specifically ''[=MarsQuest=]'' [[spoiler:LetsPlay/{{Sjin}}]] joins up with LetsPlay/LewisBrindley, LetsPlay/SimonLane and LetsPlay/DuncanJones to get to Mars and rescue the captive [[spoiler:LetsPlay/{{Sips}}]]. Once the goal is achieved, he tries backstabbing Team J.A.F.F.A, but this fails ''horribly''.
[[/folder]]

* ''VideoGame/MassEffect3'': [[spoiler: Maya Brooks]] in the "Citadel" DLC. She pretends to be a low level, bumbling but well-intentioned Staff Analyst, helping to uncover the assassin who is attempting to kill Shepard by providing the team with dossiers, information, and advice. In actuality, she is behind the attempt, intending to kill Shepard and replace him with a clone that will allow her to use Shepard's connections and reputation to push her Human Supremacist agenda on the galaxy.

* ''Literature/{{Animorphs}}'' - [[spoiler:David]]. Note that no one really wanted him to join, and he didn't either, but [[spoiler:he'd found the morphing cube and his parents had been taken by Yeerks.]] He ends up [[spoiler:permanently [[ShapeshifterModeLock trapped]] in rat morph]], and his fate [[spoiler:(a MercyKill by Rachel or left to live as a rat)]] is left deliberately vague.

---> '''Spike''': Tell you what I'll do then. I'll head out, find this girl, tell her exactly where all of you are, and then watch as she kills you.
---> ''*shocked silence from Xander and Giles*''
---> '''Spike''': Can't any one of your damn little Scooby club at least ''try'' to remember that ''I hate you all''? Just because I can't do the damage myself doesn't stop me from aiming a loose cannon your way. And here I thought the evening'd be dull.

* In [[https://www.fanfiction.net/s/6310457/1/Devil-s-Advocate Devil's Advocate]] [[Anime/DigimonTamers Takato]] joins the [[Anime/DigimonAdventure02 Digidestined]] to help them defeat the Digimon Emperor. However as soon as the Emperor dies Takato plans to [[YouHaveOutlivedYourUsefulness turn on the others and kill them.]]

** [[DefiedTrope Defied]] in ''VideoGame/NEOTheWorldEndsWithYou'' with [[spoiler:Shoka]]. Originally joining the Wicked Twisters as a mole to spy on them for the Reapers' benefit, she felt incredibly guilty betraying her teammates who considered her a friend. She ends up fully defecting from the Reapers and permanently joining the Wicked Twisters.

* Wrestling/{{EVIL}} played the... well, evil version of this in [[Wrestling/NewJapanProWrestling NJPW]], betraying Wrestling/LosIngobernablesDeJapon and joining Wrestling/BulletClub in 2020. LIJ had been a full-blown heel stable when he joined, but had transitioned to being tweeners by the time he left.

* In ''Film/TheFaculty'', [[spoiler:Marybeth]] is this in a meta sense. While the other five protagonists didn't know each other before the events of the movie, they ''are'' pretty obviously based on the group from ''Film/TheBreakfastClub'' ([[JerkJock Stan]]'s counterpart is Andy, [[AlphaBitch Delilah]]'s is Claire, [[HollywoodNerd Casey]]'s is Brian, [[{{Delinquents}} Zeke]]'s is Bender, and [[MisunderstoodLonerWithAHeartOfGold Stokely]]'s is Allison), leaving one to wonder where [[spoiler: Marybeth]] fits in. The answer: she doesn't. She's the [[spoiler: [[HiveQueen queen alien]] leading the {{Puppeteer Parasite}}s that are taking over the school]].

** Defied in ''VideoGame/NEOTheWorldEndsWithYou'' with [[spoiler:Shoka]]. Originally joining the Wicked Twisters as a mole to spy on them for the Reaper’s benefit, she felt incredibly guilty betraying her teammates who considered her a friend. She ends up fully defecting from the Reapers and permanently joining the Wicked Twisters.

** Defied in ''VideoGame/NEOTheWorldEndsWithYou'' with Shoka. Originally joining the Wicked Twisters as a mole to spy on them for the Reaper’s benefit, she felt incredibly guilty betraying her teammates who considered her a friend. She ends up fully defecting from the Reapers and permanently joining the Wicked Twisters.

* ''Franchise/PowerRangers'':

** Probably the closest to this happening occurs in ''Series/ChoudenshiBioman'' in a two part story where a man tries to join the team and fights beside them but he gets rejected when he turns out to not have any powers. The villains take advantage of him by tricking him into letting them turn him into an evil ranger the others have to defeat. Unlike future sixths rangers he does not keep his powers after he is freed.

* [[spoiler:Goro Akechi]] in ''VideoGame/Persona5''. Subverted in that [[spoiler:the gang already knew he was TheMole from the start and actually finds a way to counter his plan (to kill Joker and have the Phantom Thieves arrested) with a very clever BatmanGambit]].

** There's also EVA-03 and its pilot, however the case of their betrayal was unintentional, as an Angel managed to hijack them before they even made a sortie.

** In the anime, [[spoiler:Crona decides to stop working for Medusa]] and leave the DWMA out of guilt. Maka catches them on the way out and convinces [[spoiler: Crona]] to stay and be their ally for the rest of the show.
** In the manga, [[spoiler:Crona disappears just after being discovered]], having been called back by Medusa to her lair. Eventually, [[spoiler: Crona kills Medusa, but thought so lowly of themself for it that [[spoiler: Crona decides to become a Kishin as Medusa planned]] and cause TheEndOfTheWorldAsWeKnowIt. Maka manages to talk [[spoiler: Crona]] back, but by that point [[spoiler: Crona]] had done so much wrong they ended up being a BarrierMaiden for the rest of their immortal life as repentance, or until Maka manages to rescue them, depending on your personal interpretation.

[[folder:Western Animation]].

* ''VideoGame/GrimFandango'': Shortly after joining the LSA, [[spoiler:Olivia betrays Manny and the rest of the group for her new boyfriend,[[BigBad Hector LeMans]].]]