%% Image removed per Image Pickin' thread: http://tvtropes.org/pmwiki/posts.php?discussion=1362016383065992300
%% Please start a new thread if you'd like to suggest a new image.
%%
->''"Don't be a fool. The only one I ever loved was God. And that was a ''[[TimeAbyss long]]'' time ago!"''
-->-- '''ArchangelLucifer''', ''Series/{{Brimstone}}''

So you have your EccentricMentor and with his backing you're facing off against the nefarious machinations of the local EvilSorcerer, when suddenly you learn a shocking truth -- in their youth, rather than being bitter enemies, these guys were best friends!

This trope occurs whenever a good aligned character (sometimes TheHero, but more commonly TheObiWan, the EccentricMentor, the SupportingLeader, or the BigGood) is revealed to have had a history as friend, ally, mentor, or even student with a major villain (commonly the BigBad, but sometimes TheDragon or another high-ranking [[EvilMinions Evil Minion]]). Usually the friendship fell through simply because the future villain went power mad and the other character didn't want any more to do with it, but more complex and unusual variations exist. Sometimes it will be known all along, but sometimes it will be the subject of a dramatic reveal that can lead TheHero and the audience to reevaluate what they know about both characters.

As the top of the page indicates, tends to happen a disproportionate amount of the time with the resident [[EccentricMentor Wise Old Wizard]] and the EvilSorcerer. Compare and contrast BigBadFriend, where the revelation occurs during the story and the "Bad" character was evil all along (or at least had been for a while) and would rather remain friends despite this. Usually, either the evil character will be a FallenHero or the good one will be TheAtoner (or both, if both started out more morally grey). The evil character will most likely be an EvilCounterpart and/or ShadowArchetype for the good one, and may also be their ArchEnemy. If traces of the past friendship still exist, they might be FriendlyEnemies or even have FoeYay. Compare and contrast RivalTurnedEvil, for where the friendship broke up over personal rivalry before one of the characters turned evil (though certain examples will overlap, not all will). A less extreme version of the falling-out is WeUsedToBeFriends.

Note that this is about friends who turned evil in the {{Backstory}} and are either introduced or established in their first appearance as villains. If the friend turns evil over the course of the work, see FaceHeelTurn.

----
!!Examples

[[foldercontrol]]

[[folder: Anime & Manga]]
* In ''{{Naruto}}'', Jiraiya, Tsunade and Orochimaru were once on the same squad. Jiraiya was Orochimaru's closest friend, before Orochimaru abandoned the Leaf Village. Jiraiya chased him down and tried to talk him out of it, but Orochimaru laughed in his face.
** Kazuma of the 12 Guardian Ninjas filler arc was one to Asuma, as they served together in the Guardian Ninjas until Kazuma betrayed the group with five of his comrades to pursue their extremist agenda of making the daimyo the sole authority of the nation.
** Tobi has been revealed to be Obito Uchiha, Kakashi's best friend and role model. The pain of this revelation left Kakashi reeling in shock long enough to nearly be killed.
** And of course there's Sasuke, [[ChronicBackstabbingDisorder who betrayed Konoha and Naruto to follow in Orochimaru's footsteps only to betray him, too, join the Akatsuki, and then betray them, all the while forming his own faction. A member of which he tried to kill after abandoning the others]].
*** This hearkens back to his own relationship with Itachi. Sasuke absolutely adored his older brother, only for him to murder their entire clan. His conflicting love for his brother and hate for what he had done were eventually used by Tobi to manipulate him.
** [[spoiler:Madara Uchiha and Hashirama Senju]] were good friends despite the intense rivalry between their clans, enough that after years of war they were able to work together to [[spoiler:found Konoha]]. Despite this, the mistrust of [[spoiler:Hashirama's brother]] eventually convinced [[spoiler:Madara to turn his back on Konoha and become the BigBad]].
* ''Manga/SoulEater'''s [[TheGrimReaper Shinigami]] and [[HumanoidAbomination Asura]].
* Yuka Sugimoto is this to Youko Nakajima in TheTwelveKingdoms, sort of. [[spoiler: She gets better once defeated, tho.]]
** In different degrees, also [[spoiler: Youko and Yuka's boyfriend Asano. He ''is'' closer to Youko than Yuka is, having known the future Queen of Kei from childhood.]]
* Enchu was formerly close friends with [[MuhyoAndRoji Muhyo]] and Yoichi, but turned to evil after his mother died and Muhyo became an executor instead of him, and serves as the main antagonist for much of the story.
* Toguro toward Genkai in Manga/YuYuHakusho.
* [[GeneralRipper Regius]] for Zest in MagicalGirlLyricalNanohaStrikerS. The two used to be friends while serving together in the bureau, and wanted to ensure that the Bureau's ground forces were able to deal with criminals and other threats. Over time, Regius lost sight of his ideals as he fell under the sway of the High Council, and eventually [[spoiler:Zest and nearly all his team were killed on a raid on a Combat Cyborg facility]]. Zest, [[spoiler:after being cloned]], sought out Regius for answers on why he changed, [[spoiler:but Due killed Regius before he could give any]].
* In ''FushigiYugi'', Miaka and Yui are both best friends until the two are pitted against each other. The odd thing about this particular example is that Yui is deceived into thinking Miaka is the one who turned against her, and that she, not Yui, is the one who is turning evil.
* In ''SuitePrettyCure'', [[CatsAreMean Siren]] and [[CuteKitten Hummy]] used to be the best of friends until Hummy took Siren's title as singer of the annual "Melody of Happiness", causing the latter to defect to the villains' side. They ''almost'' made up early in the series before [[BigBad Mephisto]] [[BrainwashedAndCrazy forcefully won Siren's loyalty back]]. However, they do get a proper reconcilliation about nine episodes later, leading to Siren joining the team as [[SixthRanger Cure Beat]].
* Who else but Guts and Griffith of ''{{Berserk}}''? The two men had a bond bordering on brotherhood (or if you're that way inclined, [[HoYay more than that]]), only for Griffith to turn his back on him and everyone else he led during the events of the Eclipse, which would destroy this bond forever and leave Guts with an undying hatred for Griffith.
* In ''Manga/{{Akira}}'', Tetsuo is this to Kaneda. Both have been friends since their first meeting in an orphanage.
* ''KenichiTheMightiestDisciple'': [[spoiler:Odin a.k.a. Ryuto Asamiya]] used to be friends with the titular character before a fight that led to him holding a years-long grudge. He's also a ForgottenChildhoodFriend, as Kenichi initially didn't recognize him in the present day.
* Shin used to be Kenshiro's best friend in ''Manga/FistOfTheNorthStar'' up until he was manipulated by Kenshiro's evil brother Jagi into turning against him and taking Yuria, who both Kenshiro and Shin loved, for himself.
* In ''Manga/RaveMaster'', Gale Raregroove, aka King the leader of Demon Card, and Gale Glory, Haru's father, used to be the best of friends. A huge helping of tragedy and poor decisions made them bitter enemies. The worst part is that it's implied near the end of the series that this was partly due to fate constantly screwing over the Raregroove bloodline.
[[/folder]]

[[folder: Comic Books]]
* Professor X and {{Magneto}} in most versions of the ''Franchise/{{X-Men}}''.
** Wolverine and Sabretooth. ''First X-Men'' actually shows us why the two went their separate ways. After forming a group of mutant rebels to fight the government, Victor wants to take off with his love interest and leave the fighting to someone else. However, Wolverine, by that point, had already convinced everyone that what they were doing was necessary, so she stayed. She is killed in the final conflict, but instead shows Victor a vision of her getting better, and the two having a family and living a happy life, before cutting the illusion and telling Creed taht ''that'' is what he should remember, and that it doesn't have to mean anything less. Creed took this to heart, blaming Logan for taking away his happy ending, and told Logan that he would ensure that he never find anything or anyone worth living for.
* {{Superman}} and LexLuthor, in [[SilverAge some]] [[Series/{{Smallville}} versions.]]
* [[ComicBook/TwoFace Harvey Dent]] is shown as a close friend of both Franchise/{{Batman}} and Commissioner Gordon before turning into Two-Face, particularly in ''ComicBook/TheLongHalloween''.
** Black Mask and Hush were both Bruce Wayne's childhood friends, having turned into supervillains in their adult lives.
* Apparently Megatron and Optimus were this in the [[TheTransformersIDW IDW]] continuity and in the Movie prequel comics and [[Comic/TheTransformers Marvel UK annuals]] as well.
* On Tatooine, Luke Skywalker only had two friends who shared his desire to go offworld, and both, being older than him, joined the Imperial military before ANewHope. Biggs Darklighter became a pilot, [[DefectorFromDecadence defected]] to the Rebellion, and [[MauveShirt died at Yavin]]. Luke's other friend, Janek "Tank" Sunber, was shown [[Franchise/StarWarsExpandedUniverse in the comics]]; he washed out of pilot training and became an infantry officer. Of course, he came into conflict with Luke.
* In the {{New 52}}, {{Nightwing}}'s newest foe Saiko [[spoiler:is former friend and fellow former member of Haly's circus Raymond. Raymond was taken by the Court of Owls and put through TrainingFromHell to become a Talon, only to be washed out and left for dead with his eyes pecked out by birds.]] Saiko hates Dick Grayson because [[spoiler:the Court only took Raymond because they couldn't get Dick, their original candidate, after Bruce Wayne adopted him in the wake of the Flying Graysons' deaths.]]
* [[ComicBook/FantasticFour Reed Richards]] and SelfDemonstrating/DoctorDoom were college students who could only find intellectual debate and stimulation from each other, until Reed pointed out a mistake in Victor's schematics which was part of his last step in his StartOfDarkness.
* In ''TheFlash'', there's Hunter Zolomon, formerly a close FriendOnTheForce to Wally West, before Gorilla Grodd broke his back and set the stage for him to become [[EvilCounterpart Zoom]].
[[/folder]]

[[folder:Films -- Animated]]
* ''WesternAnimation/ToyStory3'' Inverts this: Chuckles the Clown was friends with [[spoiler: Lotso]], who is the BigBad. Witnessing [[spoiler: Lotso]] become a monster resulted in him becoming bitter and cynical.
* [[spoiler: Dr. Glickenstein]] to the titular character in ''WesternAnimation/{{Igor}}''.
[[/folder]]

[[folder:Films -- Live-Action]]
* ''Franchise/StarWars'':
** Darth Vader and Obi-Wan are a double-hitter, as Vader (as Anakin Skywalker) was both Obi-Wan's student and his closest friend.
** Count Dooku was also once a respected Jedi Master who got on well with his former teacher Yoda and peer Mace Windu. In this case the revelation, especially to the characters, was the fact that he'd turned evil rather than that he had been someone's friend.
* Alec Trevelyan to Film/JamesBond himself in ''Film/GoldenEye''.
* It's a plot-point in ''Film/{{Unbreakable}}'', and the last spoken lines in the film are the evil former friend specifically talking about it as a trope in fiction.
* TheDragon Maxim Horvath is this to Balthazar Blake in ''Film/TheSorcerersApprentice''. Also a case of LoveMakesYouEvil, as he became evil after Veronica Gorloisen rejected him in favor of Balthazar.
* Steve Rogers and [[spoiler:Bucky Barnes/Winter Soldier]] in ''Film/CaptainAmericaTheWinterSoldier''.
* ''Film/XMen'':
** Naturally while Magneto remains on FriendlyEnemy terms with Charles Xavier, the X-Men and Brotherhood are at great conflict in the majority of films regardless.
** Pyro to Bobby.
[[/folder]]

[[folder:Folklore]]
* Popular folklore has Billy the Kid and Pat Garret as an example of this, although their friendship was never actually documented.
[[/folder]]

[[folder:Literature]]
* Several times in ''Literature/HarryPotter'' -- Albus Dumbledore and Gellert Grindelwald were best friends (and [[HoYay a bit more]], at least on Albus's end). Later on, Tom Riddle, the future Lord Voldemort, was Dumbledore's student, and at least one of the Sorting Hat's songs implies that Godric Gryffindor and Salazar Slytherin were once good friends as well.
** Subverted with Sirius Black, who looks like the evil part of this in comparison to Harry's dad, but is revealed to have been framed. Played straight with Peter Pettigrew, another former friend who ''was'' guilty and did the framing.
** As well as [[spoiler:Lily Evans and Severus Snape]], until the latter's HeelFaceTurn.
* Gandalf and Saruman from ''Literature/TheLordOfTheRings'' have elements of this, though their relationship doesn't shatter until early in the present storyline (though the books at least show that it had been fraying for a while before that because of Saruman's jealousy).
** They had never been exactly good buddies; according to the [[AllThereInTheManual Appendix]] Saruman had been jealous of Gandalf almost as soon as they stepped off the ship in the Gray Havens, but they had had mutual respect and a common purpose.
* [[EvilSorcerer Akhlaur]] and [[ReasonableAuthorityFigure King Zalathorm]] from ''CounselorsAndKings'' were once best friends, until Akhlaur proved that WithGreatPowerComesGreatInsanity.
* ''{{Warbreaker}}'' has Vasher and Denth as an interesting variation [[spoiler: because the friendship ended violently over something ''Vasher'', the good guy of the two did. They were originally part of the same group of famous magic-users, and Vasher killed Denth's sister, another member, fearing that her knowledge of how to create Artifacts of Doom would spread. Denth went on a RoaringRampageOfRevenge to avenge her, gradually descending into evil in the process.]]
* In ''Literature/TheDeathGateCycle'', [[WellIntentionedExtremist Samah]] and [[EccentricMentor Zifnab]] were at least cordial colleagues and possibly friends, at least until Samah went all KnightTemplar and Zifnab dedicated himself to opposing him.
* Though calling them "friends" would be a stretch (he was never a particularly ''nice'' guy), Zedar from ''TheBelgariad'' was once a Disciple of Aldur along with the EccentricMentor Belgarath, and the two worked closely together and respected each other. Then [[BigBad Torak]] {{Mind Rape}}d Zedar into becoming TheDragon, and it went rapidly downhill from there.
* From the ''SagaOfDarrenShan'' [[spoiler: Darren's former best friend, Steve]].
* From ''TheElenium'', comparatively rare example of the main hero having a prominent villain as one of these- Martel and Sparhawk were good friends who went through MagicKnight training together, until Martel got caught practicing BlackMagic and was expelled from the order. Though now enemies, they're still very polite to each other and respect each other's abilities, and conduct their final duel in a most gentlemanly manner.
** From ''The Tamuli'', Sephrenia and Zalasta had been friends from childhood, and Styric lifespans are very long. It didn't end well. [[spoiler: Unfortunately for everyone, Zalasta was driven by a very extreme case of LoveMakesYouEvil.]]
* Alan Garner's ''Literature/TheWeirdstoneOfBrisingamen'' ends with a fight between Cadellin and Grimnir, the evil wizard. When [[spoiler: Cadellin kills Grimnir, he reveals that they were once friends [[CainAndAbel and brothers]].]]
* In MemoirsOfAGeisha, Sayuri and Pumpkin, who started out as friends, but once [[spoiler: Mother adopted Sayuri instead of Pumpkin and she became a more popular geisha than Pumpkin]], they became rivals (at least in Pumpkin's mind).
* In PercyJacksonAndTheOlympians, Luke was this to Annabeth and Thalia.
[[/folder]]

[[folder: Live-Action TV]]
* Oliver and [[spoiler:Slade Wilson/Deathstroke]] on ''{{Arrow}}''.
* Giles and Ethan from ''Series/BuffyTheVampireSlayer''
-->'''Ethan:''' Oh, so cross Ripper. We used to be friends. When did all that fall apart?
-->'''Giles:''' About the same time you started to worship chaos.
-->'''Ethan:''' Oh. Religious intolerance. Sad, that. I mean, just look at [[UsefulNotes/TheTroubles the Irish Troubles]].
* ''BurnNotice'' has Michael Westen's former partner-in-spying Larry Sizemore, who becomes a PsychoForHire after he faked his death in Serbia. He shows up in Miami running a sort of freelance assassination business; he shows up in a few episodes, during which he forces Michael into Enemy Mine situations.
* The Doctor and the Master, from ''Series/DoctorWho''. They're still sort of FriendlyEnemies, but when they were schoolkids together, they weren't enemies at all, and the Doctor has some serious angst about this.
-->''"Do you remember my fatherís land back home? Pastures of red grass, stretching far across the slopes of Mount Perdition.'' ''[[MeadowRun We used to run across those fields all day,]]'' ''[[HoYay calling up at the sky...]]'' ''[[FoeYay Look at us now."]]''
* ''Series/HouseOfAnubis''. For Sarah Frobisher-Smythe, both Victor Rodenmaar and Rufus Zeno fit this trope. Victor and Rufus, being the two major villains of season 1 and both major again in season 2, as well as both antagonizing Sarah for a secret she doesn't have, were both once Sarah's childhood friends and eventually business partners, until they both became corrupted with power and greed and turned on her, and each other as well.
* On ''Series/{{Justified}}'' US Marshal Raylan Givens and local criminal Boyd Crowder grew up in the same community and then 'dug coal together' in the local coal mine. The show starts when Raylan is forced to return to Kentucky and has to confront Boyd who in the meantime became the leader of a Neo-Nazi gang of bank robbers.
* Regina to Snow White on ''Series/OnceUponATime.'' It's played for a fair amount of tragedy too. There are a number of scenes devoted to showing how Regina changed from a kind, caring young girl to a vicious [[EvilSorcerer Evil Sorceress]].
[[/folder]]

[[folder: Mythology & Religion]]
* In NorseMythology, Odin and Loki were once [[BloodBrothers sworn brothers]].
* Many tellings of the {{Satan}} story will have pre-Fall Lucifer as God's favorite angel. In some, he was Archangel Micheal's closest friend.
[[/folder]]

[[folder:Theatre]]
* Delia Ketchum used to date Giovanni in the ''Theatre/PokemonLive'' musical. In an original draft of the show, Giovanni was Ash's father.
* ''Theatre/{{Wicked}}'' has an interesting take on this (and this is true for the novel as well): although neither Elphaba nor Glinda is truly a villain in the novel at hand, its entire premise is that it functions as backstory to the original ''Film/TheWizardOfOz''. If one were to take ''Wicked'' as behind-the-scenes canon for ''Wizard'', Elphaba's and Glinda's relationship -- as friends in the former and on opposite sides of the conflict in the latter -- would certainly qualify.
[[/folder]]


[[folder:Toys]]
* In LEGO's ''LegendsOfChima'' line, the main protagonist Laval of the lion tribe used to be friends with Cragger of the crocodile tribe before the latter got a taste of [[SuperSerum Chi]] and inadvertantly started the war that the story revolves around. Similarly, he was friends with Worriz of the wolf tribe before they allied themselves with the crocs under Cragger's leadership.
[[/folder]]

[[folder: Video Games]]
* Athos and Nergal from ''VideoGame/FireEmblem''.
* ''Franchise/AceAttorney'':
** Phoenix Wright and Miles Edgeworth in ''Phoenix Wright: Ace Attorney''. [[spoiler:Miles and Phoenix were good friends in elementary, until the DL-6 incident which killed Miles' father and traumatized Miles. Then to put the icing on the cake, Manfred von Karma adopted Miles and raised him in the corrupt ways of the Von Karma family. The two friends meet again in the courtroom; Phoenix on the defense bench and Miles on the prosecutor's bench.]] Then, as the series goes on, [[spoiler:they become friends again, or at least win back each other's respect, as Edgeworth gains CharacterDevelopment.]]
** Case 1-5 has this with Lana Skye and her old co-workers, Angel Starr and Jake Marshall. They all worked together to catch the serial killer Joe Darke, but then Lana grew cold and distant and rumors began to fly that she was using less-than-legitimate methods to catch criminals. [[spoiler:As it turns out, she was being blackmailed.]] This is also implied to be the case between the Judge and [[spoiler:Damon Gant]].
** Subverted in ''Dual Destinies'', with [[spoiler:Athena and Simon]]. While they had once been friends [[spoiler:when Simon worked with Athena's mother, and apparently ended up killing her,]] it's revealed that [[spoiler:not only was Simon not the murderer, Athena never believed he was and has spent her life trying to prove it.]]
* Dr. Light and Dr. Wily had this relationship in ''VideoGame/MegaMan''.
* Porky and Ness in ''VideoGame/EarthBound'' were likely once close friends. [[spoiler: [[FightingYourFriend Until things went horrendously out of control]].]]
* Revan and Malak in ''VideoGame/KnightsOfTheOldRepublic''. Inverted in that it's common knowledge that they used to be friends; the twist is that Revan is still alive and back with the Jedi. During their final confrontation, a redeemed Revan can even apologise for leading their friend down the path to the Dark Side, but note that it was ultimately Malak's decision to continue down that path.
* The lead signature characters of ''VideoGame/CityOfHeroes'' and ''City of Villains'', Statesman and Lord Recluse, respectively, were best friends before Recluse joined Arachnos.
* [[Anime/CodeGeass Kallen Kozuki]] and [[Anime/MobileSuitGundam00 Louise Halevy]] in ''VideoGame/{{Super Robot Wars Z}}2''. [[http://www.youtube.com/watch?v=DZdwkxjT6r4 Louise calls out Kallen for working with ZEXIS]], even though Louise works for the A-LAWS.
-->'''Louise''': Kallen! You deceived me!
* Pigma Dengar was on the original VideoGame/StarFox team before his betrayal.
* In ''{{Transformers}}: WarForCybertron'' it's taken it UpToEleven, with Optimus being swayed to help start Megatron's rebellion, and even successfully lobbying for the Council to grant the rebels an audience... where Optimus argued his understanding of ''Megatron's'' cause so well, the Council agreed and named Optimus the next Prime. Megatron saw this as a betrayal, and started the civil war, anyway. NiceJobBreakingItHero, indeed.
* "Arthur," in the Sega Genesis version of ''{{Ghostbusters}}'', to the Weapons Shop owner.
--> "Did Arthur die? Once he was my friend. After he found the stone tablet he changed, but a long time ago he was a good man. To restore his good name, I'll repay you for your costs."
* ''VideoGame/{{Persona 3}}'''s backstory has strong shades of this. Nearly everyone in the know about the Dark Hour (outside of about half your party) used to work together for the Kirijo Group's "Ergo Division" that researched Personas and Shadows, or were involved in their initial researches. Not all of them may have been ''friends'', as such (Strega has a very understandable grudge against Kirijo), but there are a lot of old professional relationships gone sour due to [[spoiler:Mitsuru's grandfather]]'s megalomania and the disasters it caused (and continues to cause).
[[/folder]]

[[folder: Web Original]]
* In one story in the WhateleyUniverse, Phase muses on how a lot of the time, villains started off as the hero's best friend, and wonders if one day he'll end up enemies with his friends Mal and Jadis, who are the children of supervillains (Mal wants to be a villain and Jadis hasn't said whether she wants to be a hero or not, though the answer is probably yes).
[[/folder]]

[[folder: Web Video]]
* Anyone who has played ''Franchise/MortalKombat'' will know of the rivalry between Hanzo Hasashi (Scorpion) and Bi-Han (Sub-Zero), stemming from [[spoiler:EvilSorcerer Quan Chi disguising himself as Bi-Han and murdering Hanzo's entire clan and family]]. However, in the second season of ''MortalKombatLegacy'', we find out that they were childhood friends, despite their parents forbidding them from playing together due to the rivalry between their ninja clans. In fact, after they become the leaders of their respective clans, they declare peace, and Bi-Han is even willing to keep the peace after [[spoiler:Hanzo is forced to kill Bi-Han's brother while protecting his family]]. Shortly after that, [[spoiler:Hanzo and the the entire Shirai Ryu clan are slaughtered, apparently by Bi-Han and his Lin Kuei ninja. When Bi-Han finds out, he is ready to execute his lieutenants on the spot for this until he finds out that they weren't responsible]]. After Hanzo becomes the undead Scorpion and joins the Mortal Kombat tournament on the side of the [[TheEmpire Netherrealm]], he faces Bi-Han in combat. [[spoiler:Bi-Han's attempts to reach his childhood friend fall on deaf ears, and Hanzo ends up killing him in a gruesome way]].
[[/folder]]

[[folder: Western Animation]]
* Fire Lord Sozin, the guy who started the War and the tradition of Fire Lords being [[EvilOverlord Evil Overlords]], was once best friends with Avatar Roku on ''WesternAnimation/AvatarTheLastAirbender'', though in a variation both characters are long dead by the time the viewer learns the details of their history.
* Vlad Masters from ''WesternAnimation/DannyPhantom'' was Danny's parents' best friend in college, until a botched experiment dreamed up by Danny's dad Jack (temporarily) disfigured him (and gave him superpowers, but he didn't find that out until later). Vlad is now dedicated towards three goals- killing Jack, convincing Maddie (Danny's mom) to fall in love with him, and making Danny his apprentice. Ironically, [[GeniusDitz Jack]] is the only one ''completely'' oblivious to all this.
** In an episode where Danny tries to stop the accident that turned Vlad into a ghost, it was shown that Vlad was ''already'' jealous of Jack and his relationship with Maddie, and implies he would have still sought out Maddie even without ghost powers.
* Plankton to Mr. Krabs in ''WesternAnimation/SpongebobSquarepants''.
* ''WesternAnimation/TheBatman'' gives us Ethan Bennett, both a high-school friend of Bruce Wayne's and one of the only cops willing to give Batman a chance. [[spoiler:Naturally, he's accidentally turned into Clayface in the Season 1 finale. He eventually becomes a good guy again after spending a while in the HeelFaceRevolvingDoor.]]
* The Shredder had this relationship with the Ninja Tribunal in the second ''[[WesternAnimation/TeenageMutantNinjaTurtles2003 Teenage Mutant Ninja Turtles]]'' series.
* In ''WesternAnimation/BatmanTheAnimatedSeries'', Harvey Dent starts off as a close friend of Bruce Wayne before he becomes Two-Face.
* Terry [=McGinnis=] also received this treatment when his old friend fell back into crime and became Big Time in ''WesternAnimation/BatmanBeyond''.
* In season 3 of ''WesternAnimation/XiaolinShowdown'', we discover that Chase Young is this to [[spoiler:Master Monk Guan]] from before Chase was [[DealWithTheDevil turned Heylin by Hannibal Bean.]] [[spoiler:Technically, he is this to Grand Master Dashi as well, except that Dashi is assumedly dead in the present.]]
* In [[WesternAnimation/TheTransformers the original Transformers cartoon]], Starscream used to be Skyfire's best friend before the war.
** Similar to Cy-Kill and Leader-1 below Optimus and Megatron used to be close as brothers in ''WesternAnimation/TransformersPrime''.
* Cy-Kill used to be Leader-1's closest comrade in ''WesternAnimation/ChallengeOfTheGoBots.'' He defected out of jealousy over Leader-1's successes.
* In {{WesternAnimation/MASK}}, Matt Trakker and Miles Mayhem were friends who formed MASK together, before Mayhem stole some of the masks and used them to set up VENOM.
* Wheeljack in ''Anime/TransformersArmada'' was friends with Hot Shot before Hot Shot betrays him...or so Wheeljack thinks. Turns out Hot Shot tried to go back and save him, but failed.
* In ''Franchise/{{Bionicle}}'''s 2004 line, Lhikan and Nidhiki use to be close friends as Toa, but Nidhiki betrayed his fellow Toa to the Dark Hunters. When his plan failed, Nidhiki was transformed into an insectoid monster.
* In the ''WesternAnimation/CaptainNTheGameMaster'' episode "The Most Dangerous Game Master" Dr. Wily builds an android rival based on Kevin's memories of a school bully. Later we find out Kevin and the bully used to be friends, and since the bully was created from Kevin's memories he still retains his good traits and Kevin is able to befriend him again.
* General Modula, the BigBad of ''WesternAnimation/SymBionicTitan'', was this to the King of Galaluna prior to the series, also as seen in a flashback in "Shadows of Youth."
* [[CainAndAbel Nightmare Moon to Princess Celestia]] in ''WesternAnimation/MyLittlePonyFriendshipIsMagic''. Prior to her FaceHeelTurn, she was Princess Luna, a co-ruler of Equestria alongside her sister. [[spoiler:They eventually patch things up once Luna is purged of her SuperpoweredEvilSide and its influence.]]
* In ''WesternAnimation/{{SheZow}}'', Tara was the sidekick to Guy's aunt Agnes, the previous [=SheZow=], but eventually faded into obscurity. When she first appears she wants to bury the hatchet, but Guy not knowing who she is causes her to snap and challenge him to a duel instead, namely "GLAMAGEDDON-GEDDON-GEDDON!"
* In ''WesternAnimation/ElTigre: The Adventures of Manny Rivera'', White Pantera's ex-sidekick, the Titanium Titan, turns evil after White Pantera's son Manny was born and resents him for having his partner's attention. He becomes obsessed with getting rid of El Tigre so he can have White Pantera to himself again.
* Penny to Bessie from ''WesternAnimation/TheMightyB''. She also conbined this with TheEeyore and WoobieDestroyerOfWorlds tropes.
* Nester to Scaredy in ''WesternAnimation/ScaredySquirrel''.
[[/folder]]

----