History Main / BigBadSlippage

* ''{{Manga/Remina}}'' has Naoya Goda, the president of the human Remina's official fanclub, as well as her biggest fan. Throughout the first half of the story, he's nothing more than a really obsessive, creepy fanboy of the titular main character, and is seen constantly competing with people for Remina's affection. He eventually saves her like he promised, though Remina still doesn't show much affection back towards him, too distraught by the deaths of her loved ones. Goda becomes the main anatagonist of the manga as soon as Remina calls him "the worst" for beating up Kunihiro over the amount of dedication he has for her, in that he becomes the cult's new leader, and wants her, along with anyone associated with her, to die as slowly and painful as possible.

* ''Manga/Remina'' has Naoya Goda, the president of the human Remina's official fanclub, as well as her biggest fan. Throughout the first half of the story, he's nothing more than a really obsessive, creepy fanboy of the titular main character, and is seen constantly competing with people for Remina's affection. He eventually saves her like he promised, though Remina still doesn't show much affection back towards him, too distraught by the deaths of her loved ones. Goda becomes the main anatagonist of the manga as soon as Remina calls him "the worst" for beating up Kunihiro over the amount of dedication he has for her, in that he becomes the cult's new leader, and wants her, along with anyone associated with her, to die as slowly and painful as possible.

* ''[[Manga/Remina]]'' has Naoya Goda, the president of the human Remina's official fanclub, as well as her biggest fan. Throughout the first half of the story, he's nothing more than a really obsessive, creepy fanboy of the titular main character, and is seen constantly competing with people for Remina's affection. He eventually saves her like he promised, though Remina still doesn't show much affection back towards him, too distraught by the deaths of her loved ones. Goda becomes the main anatagonist of the manga as soon as Remina calls him "the worst" for beating up Kunihiro over the amount of dedication he has for her, in that he becomes the cult's new leader, and wants her, along with anyone associated with her, to die as slowly and painful as possible.

* Eren Yeager from ''Manga/AttackOnTitan''. His entire character arc toward the end of the series has culminated in an intention to massacre the entire world outside of the Eldians. He has already murdered thousands of innocent people, and this is a character who was previously a relatively standard, idealistic and morally upright StockShonenHero. His TrueCompanions Armin and Mikasa have [[EnemyMine teamed up with their former enemies Reiner and Annie to take him down; all in all, he has slowly descended into becoming the BigBad of his own series.]]

A SubTrope of FaceHeelTurn. Can also coincide with SlowlySlippingIntoEvil. When a rebel leader undergoes this, it's also a case of TheParagonAlwaysRebels. Can coincide with ThenLetMeBeEvil, when a character who has been treated as evil, regardless of their actions, says "screw it" and decides to meet everyone's expectations by being evil. Compare StartOfDarkness, which shows how the character became evil via a {{prequel}} story or {{flashback}}s. Compare ProtagonistJourneyToVillain, when the main protagonist crosses over to the dark side (but does not necessarily become a BigBad) over the course of the story. Contrast EvilAllAlong, where the character is always evil rather than just slipping into evil. This doesn’t preclude said character returning to the side of good, in which case they’re liable to become TheAtoner. See also UsedToBeASweetKid, where a character used to be nice before becoming evil.

* [[spoiler: Eren Yeager]] from ''Manga/AttackOnTitan''. [[spoiler: His entire character arc toward the end of the series has culminated in an intention to massacre the entire world outside of the Eldians. He has already murdered thousands of innocent people, and this is a character who was previously a relatively standard, idealistic and morally upright StockShonenHero. His TrueCompanions Armin and Mikasa have [[EnemyMine teamed up with their former enemies]] Reiner and Annie to take him down; all in all, he has slowly descended into becoming the BigBad of his own series.]]

* When Zamasu is introduced in ''Anime/DragonBallSuper'', he's a well-meaning Supreme Kai apprentice who thinks the Kais could better help mortals if they were to directly interfere. As the story goes on, he drops from 'Gods should help mortals more' to '[[HumansAreBastards Mortals Are Bastards]] and helping is useless', to '[[HumansAreTheRealMonsters Mortals Are The Real Monsters]] and the gods' mistake was letting them exist in the first place', to [[spoiler: 'Everyone who's not me is the real problem, and I should commit omnicide to correct it', with a side of 'I should torture Goku by switching bodies with him and killing him and his family in revenge for Goku being stronger than me']]. While there was clearly something off with him in the first place, since the trigger for him going off the deep end was [[EvilIsPetty petty anger]] against Goku for beating him in a sparring match (anime)/achieving Super Saiyan Blue and thus god-level strength (manga), that's still quite a ways to fall.

* ''Literature/AFrozenHeart'', a BroadStrokes retelling of ''WesternAnimation/{{Frozen|2013}}'', goes into the backstory and perspective of [[spoiler:[[TragicVillain Prince Hans]]]]. Back home, he's the abused 13th and youngest son of an evil tyrant who frequently belittles him for not meeting his family's expectations. He starts out wanting to marry into Arendelle's royal family as a way to escape his home and start a new life, but his obsession with [[WellDoneSonGuy earning his father's respect]] causes him to become much more ruthless, turning into the character we see in the film.
* In ''Literature/{{Gormenghast}}'', Steerpike begins as a rebel dissatisfied with the lowly position allocated to him at birth. He runs out on his assigned job as a kitchen scullion and sets about — metaphorically and literally — climbing to a higher social station, despite the law and tradition of the city-state. In the beginning, the reader can sympathise with him for his ambition, for wanting to break with stultifying convention, for wanting to get a satisfying position in line with his intelligence and talent. An occasional lie and a bit of confidence trickery can be forgiven. But then people start to die. The sympathetic young rebel is becoming a monster. He finally dies as a scarred and deformed monster, having murdered the heroine Fuchsia and been hunted down by her brother.
* Claude Frollo from ''Literature/TheHunchbackOfNotreDame'' qualifies. Beginning the story as a caring person who adopts the baby Quasimodo out of compassion, he is later driven mad by his forbidden lust for Esmerelda, and becomes the story's main villain as a result. (This trope does not apply to the Disney version of the character, who is evil right from the beginning.)

* [[spoiler:Jiaying]] from ''Series/AgentsOfSHIELD'' is in charge of Afterlife and the head figure of the Inhumans there. While she is rather nice at first (especially to [[spoiler:her daughter, Skye]]), her nasty side begins creating a lot of conflict concerning the Inhumans, to the point where [[spoiler:Jiaying kills Agent Gonzales and starts a war between the Inhumans and S.H.I.E.L.D.]]. [[spoiler:And in a subversion, she's actually behind the actions of Cal, making her the BigBad the whole time.]] It turns out that she actually was a nice person to begin with, but was [[spoiler:vivisected by Dr. Whitehall and CameBackWrong thanks to Cal's efforts to save her]].
* Slade Wilson in ''Series/{{Arrow}}'' starts off being stuck on the island with Oliver. He helps train Oliver to make him into a skilled fighter. After being badly burned, Oliver, Shado, and Sara use the drug Mirakuru to save him. It works, but there are nasty side-effects that cause Slade to be mentally unstable. Soon after giving him the drug, Oliver, Shado, and Sara are captured and Oliver is forced to choose to save one of them; [[spoiler:he chose Sara]]. When Slade finds out, he is dead-set on destroying Oliver in every way possible.
* Walter White, a.k.a. Heisenberg from ''Series/BreakingBad''. As someone who has the longest, most complex [[FaceHeelTurn Face-Heel Turns]] ever put in television, he happens to be [[HeroAntagonist Hank]]'s main target after [[spoiler:he discovers that ''he is'' Heisenberg.]]

** The BigBad of the third season, Savitar, is [[spoiler:a time remnant of Barry Allen from the future. Savitar has not only suffered all the trauma of his past self, but was also ostracized and abandoned by his friends and family for not being the "real Barry", too. As a result, he has dedicated himself to ruining the lives of Team Flash and bending history itself to his will]].

* On ''Series/{{Grimm}}'', Adalind removes Nick's powers through a magic ritual. Juliette agrees to restore them through another ritual, but it has the side-effect of turning her into a Hexenbiest. Then she starts to have a complete morality breakdown, leading to her starting fights in bars using her new powers, setting fire to the trailer where Nick keeps his journals, and conspiring with the villains to kidnap Adalind's daughter. That last act also leads to [[spoiler:the death of Nick's mother. And leads to her being KilledOffForReal... apparently.]]
** [[spoiler: "Apparently" being the operative word." She is eventually saved and her sanity restored (though not by the main heroes.) However, it's clear that even now, "Eve" is not the Juliette of old. What she ''is'' is an awesome and terrifying HorrifyingHero. She has a ThatManIsDead reaction to her past as Juliette, but does still care about Nick enough to give Adalind an IfYouEverDoAnythingToHurtHer type warning.]]

* King Philip in ''Series/{{Knightfall}}''. His very first scene is having a friendly sparring match with the hero Landry which establishes his friendship with the Templar Order, followed by his refusal to pillage the Jews' money in order to answer the country's bankruptcy because he is not "that kind of king". But after learning that [[spoiler:Landry has been having an affair with his wife]], he grows more cruel and heartless, not to mention antagonistic against the order as a whole. By the end of the second season, [[spoiler:he had pushed away all his allies and turned into a monster who eventually carries out the purge against the Templars and has to be put down by Landry]].
* Technically, nearly all the villains from ''Series/OnceUponATime'' are examples of this, starting out as fairly nice people and then getting slowly [[BreakTheCutie broken]] [[CorruptTheCutie until]] [[AntiVillain they]] [[TragicVillain become]] [[ProtagonistJourneyToVillain monstrous.]] The main antagonist for most of Season 5A is the one we see go through this during the course of the show. She's Emma Swan, the main protagonist after she became the Dark One. After spending weeks trying to resist, she starts to do some morally ambiguous things, and when [[spoiler:Hook is fatally injured]], she completely snaps and lets the darkness overwhelm her and [[spoiler:almost lets Hook join her]].

* Jax from ''Series/SonsOfAnarchy'' starts out as a light idealistic character who is always looking for the least violent way to achieve club goals. However, as more and more impossible demands are placed on the club, he more and more turns to the violent methods he once disagreed with, in order to keep his family and friends safe. Following the [[spoiler:the murder of Opie, his best friend]], Jax takes a very dark turn, fixated on revenge. When [[spoiler:Tara, his wife, is murdered]], Jax completely spins out, to the point of [[RevengeBeforeReason tunnel vision,]] becoming the villain he never wanted to be.

* The FinalBoss of ''VideoGame/AceCombatZeroTheBelkanWar'' is Cipher’s former wingman [[spoiler:Solo Wing Pixy. In the mission ''The Inferno'', he at first acts indifferently towards the bombing of civilians, but the end of the mission has him saying: ‘Damn them all’. The next mission ''Stage of Apocalypse'', has him pull a FaceHeelTurn after Belka detonates seven nuclear bombs on their own soil, leading him to become part of a coup d’eta ‘A World with No Boundaries’, with the goal of erasing all borders.]]
* ''VideoGame/BeyondTwoSouls'': [[spoiler:Nathan]]. We get to witness signs of his gradual slippage during the course of the story, even though the most notable stages of it are revealed in the last stages (partly due to the game's disjointed narrative).

* In ''VideoGame/CriminalCaseMysteriesOfThePast'', [[spoiler:Justin Lawson]] starts as an ally of the player and the Concordian Flying Squad, often accompanying you during many investigations and being a genuinely good-hearted man aiming to eradicate crime in the city of Concordia. Unfortunately, witnessing first-hand the consequences of unrepentant [[DirtyCop police corruption]], violent [[MobWar Mob Wars]], and [[AristocratsAreEvil evil rich families]] outright fueling all of these problems over the course of the season is enough to push him [[spoiler:to become a ruthless dictator when he takes helm as the [[MayorPain city mayor]]]], turning him into the main antagonist of the game's last stretch.

* In ''VideoGame/FireEmblemFates: Conquest'', one of the main antagonists is Takumi, your younger brother on the Hoshido side. He's easily the most RecurringBoss of the Hoshido siblings, fought as many as [[spoiler:five]] times compared to elder siblings Ryoma and Hinoka, tied with three if you count the battle at the start of the route split. Each time, he only gets more and more violently enraged with you and the other [[FantasticRacism Nohrian Scum]]'s general existence and "betrayal," acting more antagonistic overall than anyone else in Hoshido, [[spoiler:even returning from his presumed suicide and acting as the FinalBoss of the route even after you've defeated [[DiscOneFinalBoss King Garon and his cronies]]. This is partially the result of the influence of the GreaterScopeVillain, though he was only able to do this so extensively due to Takumi's own anger being unchecked.]]
* ''VideoGame/FireEmblemThreeHouses'' has this happen on the Crimson Flower route. [[spoiler:After you side with Edelgard in the Holy Tomb, Rhea suffers a psychotic breakdown and becomes the BigBad, becoming more and more obsessed with getting revenge on Byleth for betraying her and "stealing" the Sword of the Creator, and she ultimately degenerates into a sociopath willing to burn Fhirdiad to the ground with all of its civilians still inside in order to kill Byleth and the encroaching Imperial army.]]

* ''VideoGame/TheGreatGaias'': Virgil Mythos starts as a party member and seems to value his friendship with Pots, [[spoiler:but it's later revealed that Pots's murder of his family caused him to develop a lust for power and revenge. When he enrolls in Sorbithia, he's upset at how he feels the Circle of Twelve is limiting him and he eventually falls for Zacharael's temptation to become his apprentice. Eventually, his ambition causes him to betray Zacharael and use the Hourgem of Valnyr for himself, leading to him learning the Singularity spell from Khargynoth. He then uses Singularity to fuse with Zacharael and Adramelech, and then [[TheStarscream feigns loyalty]] to Maultor. In the normal ending, Virgil succeeds in absorbing a weakened Maultor and manages to unseal himself 1000 years into the future, usurping Maultor/Malviticus's role as BigBad.]]

* In ''VideoGame/LiveALive'', the [[WhamEpisode Middle Ages chapter]] focuses on this. [[spoiler:Your PlayerCharacter Oersted starts off as a generic HeroicMime KnightInShiningArmor. However, repeatedly being betrayed and abandoned by his friends begins to do a number on his sanity. When his LoveInterest Alethea professes her love for the man responsible for orchestrating Oersted's downfall and commits suicide, Oersted finally snaps and transforms into the game's major villain Odio.]]

* The FinalBoss of ''VideoGame/Portal2'' and BigBad of the second half is Wheatley, your RobotBuddy from the start of the game. He spends the first half genuinely trying to help you escape the facility (so you can take him with you): unfortunately, the last step of that escape plan is [[spoiler:having him replace [=GLaDOS=] by jamming him in her mainframe.]] At first, he still talks about escaping, but the sudden influx of power, Wheatley's own inferiority complex and paranoia and [[spoiler:the fact the mainframe is ''designed'' to make AIs obsessed with testing]] means that goes south very, very quickly.
* ''VideoGame/RandalsMonday'': [[spoiler:Sally eventually becomes the BigBad after she gets [[ArtifactOfDoom the ring]]. She's with it so long that she gains its powers in full.]]

* ''VideoGame/SpaceYandere'': Luna and Melvin, the titular {{Yandere}}s, are initially just two crew members tagging along with the other characters to find a new planet AfterTheEnd. During the first two days, Luna starts off a sweet girl who wants to gain the affection of Alex, while Melvin is a creep and a jerk obsessed with Luna but not particularly dangerous. Then Luna sees Alex kissing Eden and snaps, seducing Melvin to have him hijack the robots and use them to kill most of the crew while she tries to MurderTheHypotenuse on the third day. [[spoiler:Melvin goes along with it, but when he sees that she loves Alex and not him, turns against her and tries to kill her too.]]
* ''VideoGame/SpecOpsTheLine'' combines this trope with [[spoiler:ProtagonistJourneyToVillain]] as the BigBad initially only wanted to help the suffering civillians but every attempt only slips them into further and further villainy until they end up becoming a DestructiveSavior without realizing it. [[spoiler:While Walker initially thinks Konrad is the BigBad, the former has a HeelRealization when he finds the latter having been long DrivenToSuicide, and the voice antagonizing him was all in his own mind.]]

* ''VideoGame/TalesOfVesperia'': While Duke Pantarei is presented as a cold and ruthless man in the first half of the game due to wanting to [[spoiler:kill Estelle to prevent Alexei from using her power, he's still willing to give Brave Vesperia a chance to defeat Alexei their way. However, the guild's failure to prevent the return of Zaude and the Adephagos causes him to decide that humanity cannot be trusted with the world's safety, resulting in his plan to activate Tarqaron and sacrifice all humans to destroy the Adephagos. This puts him at odds with the party, who still believe in humanity and want to use a plan that doesn't involve sacrificing them.]]
* [[JerkAss Eric Sparrow]] in ''VideoGame/TonyHawksUnderground'' starts off as the PlayerCharacter’s best friend, and while Eric is a dumbass, he’s not malevolent yet. Gradually over the course of the game he gets worse and worse, screwing over the PlayerCharacter in increasingly worse ways until he finally just becomes the BigBad and FinalBoss.
* Kenny from Season Two of ''VideoGame/TheWalkingDead'' was your ''ally'' mere episodes earlier — but his temper and SanitySlippage slowly turned him into a BigBad, while Jane, his main rival for the position at this point, came across as comparatively level-headed and affectionate towards Clementine, if rather aloof and callous otherwise, only to turn out to be equally flawed.

* ''VisualNovel/HigurashiWhenTheyCry'': The ''Satokowashi-hen'' arc of ''Higurashi no Naku Koro ni Gou'' shows the increasing antagonism between [[spoiler:Satoko Hojo]] and Rika Furude, and the resultant trigger that drove her to recreate the infernal GroundhogDayLoop out of a petty desire to keep Rika in Hinamizawa and break her mentally. By the start of ''Higurashi Sotsu'', [[spoiler:Satoko]] is firmly in villain territory, gaslighting others by injecting them with the Hinamizawa Syndrome and using TimeTravelForFunAndProfit on a whim once she gets MentalTimeTravel powers from a mysterious purple-haired sorceress.

* In book 3 of ''WesternAnimation/InfinityTrain'', [[spoiler:Simon is the deuteragonist until the end of episode 5, when his refusal to redeem himself from the Apex's ways ultimately leads him to become the season's antagonist.]]

* ''WesternAnimation/DogsInSpace'': [[spoiler: Kira demonstrated a great contempt for humanity since Garbage and his crew first encountered her. But following Garbage's near-sacrifice of his friends in what would have been a failed bid to save humanity, Kira takes advantage of his insecurities and desperation to atone to manipulate him towards her scheme of abandoning humanity to extinction in favor of finding a planet for dogs. Even if her plot could potentially end up killing the dogs she seeks to save, or permanently rob them of their sapience]].

* ''Franchise/TheFlash'' has Hunter Zolomon, the second Reverse-Flash/Zoom, who was initially introduced as a simple supporting character in the Keystone police department far into Wally West's superhero career and developed throughout years in friendship role, until his shocking FaceHeelTurn. And even that said Heel turn happens almost [[SlowlySlippingIntoEvil a year after]] when his StartOfDarkness begins upon being paralyzed by Grodd.

* Played with in ''VideoGame/CrisisCore''. Sephiroth's main character arc is him slowly slipping from Shinra's greatest SOLDIER to the BigBad of the ''Compilation of VideoGame/FinalFantasyVII''. However, he never becomes more than a peripheral antagonist to Zack, whose plotline focuses on and climaxes with his conflict with Genesis.

* In ''VideoGame/LiveALive'', the WhamEpisode Medieval chapter focuses on this. [[spoiler:Your PlayerCharacter Oersted starts off as a generic HeroicMime KnightInShiningArmor. However, repeatedly being betrayed and abandoned by his friends begins to do a number on his sanity. When his LoveInterest Alicia professes her love for the man responsible for orchestrating Oersted's downfall and commits suicide, Oersted finally snaps and transforms into the game's major villain Odio.]]

* ''WesternAnimation/DogsInSpace'': [[spoiler: Kira demonstrated a great contempt for humanity since Garbage and his crew first encountered her. But following Garbage's near-sacrifice of his friends in what would have been a failed bid to save humanity, Kira takes advantage of his insecurities and desperation to atone to manipulate him towards her scheme of abandoning humanity to extinction in favor of finding a planet for dogs. Even if it means reducing all of the canines she wants to save either dead or reduced to their nonsapient selves]].

* ''WesternAnimation/{{Megamind}}'' starts off as a VillainProtagonist BigBad. When he gets bored after seemingly ([[spoiler:but not really]]) killing his arch-nemesis Metro Man and taking over Metro City, he decides he needs a new nemesis and creates one out of Hal Stewart, attempting to shape him into a superhero known as Titan. However, WrongGenreSavvy Hal believes that getting superpowers will automatically cause Roxanne to fall in love with him, and when she still rejects him, he decides to be a super villain instead. This is what leads to Megamind's HeelFaceTurn partway through the movie.

* In ''VideoGame/LiveALive'', the WhamEpisode Medieval chapter focuses on this. [[spoiler:Your PlayerCharacter Oersted starts off as a generic HeroicMime KnightInShiningArmor. However, repeatedly being betrayed and abandoned by his friends begins to do a number on his sanity. When his LoveInterest Alicia professes her love for the man responsible for orchestrating Oersted's downfall and commits suicide, Oersted finally snaps and transforms into the game's OverarchingVillain Odio.]]

* Nancy Downs starts out as one of the main protagonists of ''Film/TheCraft'', with the film chronicling her descent into madness and villainy. She and her friends use witchcraft to try and better their lives and empower themselves, but in Nancy's case the power goes to her head and she starts using magic to control the other girls and seriously harm people she perceives as having wronged her, forcing her ex-friend Sarah to stop her.

* [[JerkAss Eric]] [[EvilFormerFriend Sparrow]] in ''VideoGame/TonyHawksUnderground'' starts off as the PlayerCharacter’s best friend, and while Eric is a dumbass, he’s not malevolent yet. Gradually over the course of the game he gets worse and worse, screwing over the PlayerCharacter in increasingly worse ways until he finally just becomes the BigBad and FinalBoss.

* Ramses in ''WesternAnimation/ThePrinceOfEgypt'' is Moses' surrogate brother at the start of the movie. He's a generally good person who has a lot of pressure put upon him by his father, and he and Moses love each other deeply. But once he becomes Pharaoh, his hard-hearted stubbornness motivated by [[WellDoneSonGuy living up to his father's legacy]] drives him and Moses to become enemies, and by the end of the film Ramses is a genocidal madman who wants Moses and all the other Hebrews dead.

* James Ironwood of ''WebAnimation/{{RWBY}}'' starts off as a member of the BenevolentConspiracy trying to save the world, more specifically Atlas, from [[BigBad Salem.]] As the series goes on, Ironwood starts to endorse increasingly ruthless and extreme methods, [[NeverMyFault refusing to acknowledge]] that his draconian measures [[FailureHero aren't working]] and that he needs to work ''with'' people instead of ordering them around. By the end of Volume 7, he's resorted to murdering people who disagree with him, and late into Volume 8 threatens to nuke an entire city if the protagonists don't comply with his plans. As Oscar points out, [[HeWhoFightsMonsters he's no different from Salem at this point.]]

* In book 3 of ''WesternAnimation/Infinity Train'', [[spoiler:Simon is the deuteragonist until the end of episode 5, when his refusal to redeem himself from the Apex's ways ultimately leads him to become the season's antagonist.]]

A SubTrope of FaceHeelTurn. Can also coincide with SlowlySlippingIntoEvil. When a rebel leader undergoes this, it's also a case of TheParagonAlwaysRebels. Can coincide with ThenLetMeBeEvil, when a character who has been treated as evil, regardless of their actions, says "screw it" and decides to meet everyone's expectations by being evil. Compare StartOfDarkness, which shows how the character became evil via a {{prequel}} story or {{flashback}}s. Compare ProtagonistJourneyToVillain, when the main protagonist crosses over to the dark side (but does not necessarily become a BigBad) over the course of the story. Contrast EvilAllAlong, where the character is always evil rather than just slipping into evil. This doesn’t preclude said character returning to the side of good, in which case they’re liable to become TheAtoner.

* [[spoiler: Eren Yeager]] from ''Manga/AttackOnTitan''. [[spoiler: His entire character arc toward the end of the series has culminated in an intention to massacre the entire world outside of the Eldians. He has already murdered thousands of innocent people, and this is a character who was previously a relatively standard, idealistic and morally upright ShonenHero. His TrueCompanions Armin and Mikasa have [[EnemyMine teamed up with their former enemies]] Reiner and Annie to take him down; all in all, he has slowly descended into becoming the BigBad of his own series.]]