History Main / SplitPersonalityTakeOver

* ''Anime/{{Trigun}}'':
** [[spoiler:Knives Millions]]'s short transition from a hugely caring and even oversensitive cute boy to a [[TheWoobie Woobie]] who hides a lot of anguish and anger management issues from his loved ones to [[spoiler:the friggin' biggest homicidal psycho in Gunsmoke's short history and the responsible of what's probably the biggest genocide in human history, period]]. The anime [[AdaptationDecay arguably oversimplifies his transformation and motivations]], making his FreudianExcuse quite ludicrous.
** The manga also suggests that [[spoiler: Legato Bluesummers]]' original personality may have been pretty ordinary and that he used to have normal human needs, but that it soon got twisted beyond recognition by years of horrifying abuse in a small town plagued by criminality (and pedophiles) in the middle of nowhere-in-{{Mordor}} and [[spoiler:not even having a name, parents, or a past worth mentioning in his view]].

* The bad endings of both ''VideoGame/CastlevaniaChroniclesOfSorrow'' games involve [[spoiler: Dracula seizing control over Soma's body]].

* In ''Mystery Trackers: The Void'' Marius Void's criminally-inclined "brother" Sirius takes over his body after killing his psychiatrist, who'd been supplying drugs to suppress the transformation.

This isn't just an [[SecretIdentityIdentity identity crisis]] or something [[IKnowYoureInThereSomewhereFight that can be wished away with good intentions]], at least [[BattleInTheCenterOfTheMind not easily.]] This is the permanent and [[LiteralMetaphor literal]] [[ThatManIsDead death of a person]]-- or at least a personality.

This is especially common if one personality is [[GollumMadeMeDoIt more dominant than the other]], or the "good" personality is subject to MindRape or a HeroicBSOD. Occasionally, a truly strong willed "good" personality can do the takeover-- although it's likelier that they'll choose to [[SplitPersonalityMerge "merge" or reintegrate]] with their evil side into a "whole" personality because GoodIsImpotent.

* Subverted in ''Manga/AhMyGoddess''. Belldandy's sister, Urd, being half-demon and half-goddess, forcibly has her good and evil halves split apart by Mara, and when they are rejoined, she finds that her demonic side is slowly slipping away, which would eventually result in her becoming a full-blown goddess. However, Keiichi and her sisters refuse to let the Urd they've come to know disappear, so they summon the only person other than the Almighty One (whom they assume won't help them since he would rather Urd become a total goddess) with enough power to safely return Urd to stable demon/angel form--the ruler of all demons and her mother, Hild. It works, but they accidentally end up convincing Hild to leave a portion of herself behind on Earth to torment them along with Mara.

** [[spoiler: Knives Millions]]'s short transition from a hugely caring and even oversensitive cute boy to a [[TheWoobie Woobie]] who hides a lot of anguish and anger management issues from his loved ones to [[spoiler: the friggin' biggest homicidal psycho in Gunsmoke's short history and the responsible of what's probably the biggest genocide in human history, period]]. The anime [[AdaptationDecay arguably oversimplifies his transformation and motivations]], making his FreudianExcuse quite ludicrous.
** The manga also suggests that [[spoiler: Legato Bluesummers]]' original personality may have been pretty ordinary and that he used to have normal human needs, but that it soon got twisted beyond recognition by years of horrifying abuse in a small town plagued by criminality (and pedophiles) in the middle of nowhere-in-{{Mordor}} and [[spoiler: not even having a name, parents, or a past worth mentioning in his view]].
%%** It also nearly happens to [[spoiler: Livio in the manga]].

* A curious example in ''[[Machinima/RedVsBlueTheRecollection Red vs. Blue: Reconstruction]]'' - when an [=AI=] is implanted in a character, the effect is described as being "of the same mind", where the two entities share thoughts. Though the host is usually able to maintain his or her identity (even if free will is lost), Agent Maine (better known as [[TheJuggernaut the Meta]]) degenerated into a mindless husk after playing host to 7 different [=AI=]s ''at once'' and stayed that way even when the [=AI=]s were removed. Of particular note is the fact that all 7 [=AI=]s were {{Literal Split Personalit|y}}ies of another [=AI=], the Alpha.

* ''WesternAnimation/TheAvengersEarthsMightiestHeroes'' has a rare consensual example -- Bruce Banner lets [[ComicBook/IncredibleHulk the Hulk]] take over his body as long as the Hulk works alongside the Avengers as a hero. Eventually, Bruce is allowed to have control for one day a month.

* ''Webcomic/DeanNalaVinny'': One of the comic's ongoing plot lines is the transformation of Nala, a regular cat into the savage Jungle Cat Nala. This transformation is triggered by the sight of certain birds. The lettering and shape of her thought ballon’s changes, and she refers to her friend Vinny (a roach) as "bug child".

* ''Webcomics/DeanNalaVinny'': One of the comic's ongoing plot lines is the transformation of Nala, a regular cat into the savage Jungle Cat Nala. This transformation is triggered by the sight of certain birds. The lettering and shape of her thought ballon’s changes, and she refers to her friend Vinny (a roach) as "bug child".

* In an episode of ''Series/CriminalMinds'', a young man's murderous and until-then unknown alter-ego permanently takes over his body, in an attempt to protect him. In a twist, the alter-ego that took over was ''female''.

* {{Inverted|Trope}}, to some extent, with [[ComicBook/IncredibleHulk the Hulk's]] son Skaar, where the weaker, more vulnerable personality ('puny' Skaar) has recently managed to escape Skaar's suppression of him in their shared mind.
* ''ComicBook/TheIncredibleHulk:''
** ComicBook/BettyRoss was in constant risk of this when she was Red She-Hulk.
** The reason Doc Samson turned evil in the ''Red Hulk'' arc; he developed another set of personalities- his current persona, the identity of Doctor Leonard Samson [=PhD=], and the more ruthless 'Samson'- and a 'psychiatric evaluation' in his own mind organised by ComicBook/{{MODOK}} saw Samson kill the other two.

* ''Series/KamenRiderOOO'': Ankh has been reduced to a disembodied arm at the start of the show, with no knowledge of what happened to the rest of his body. The body is eventually revealed to have come back to life without his mind in it and developed its own childlike personality, referred to in external material as Lost Ankh. Both attempt to consume each other once they meet, with Lost Ankh proving the stronger and eventually winning out after several skirmishes. Eiji's eventually able to kill Lost Ankh, and the original Ankh resurrects from his remains.
* ''Series/KamenRiderBuild'': Some [[ItMakesSenseInContext demonic possesion shenanigans]] late into the story cause the original identity of [[spoiler: Takumi Katsuragi]] to resurface and replace the person he was for the past year and half without knowing about anything that happened through that time.

* Ichigo is a special case, as his Hollowfication happened during his training for Shinigami powers. He did eventually learn how to control his Hollow powers; and in the final arc, it's revealed [[spoiler:to be the basis for his shinigami power and his zanpakutou's sealed form]].

* One of the main plot points of Riku's story in ''VideoGame/KingdomHeartsChainOfMemories'' and its remake is that Riku is fighting off the last of Ansem's darkness within his Heart. Several times he almost falls to it, and once he actually does, however how it happens depends on the version. In the original, after completely dominating Lexaeus in their fight, the latter ''blows himself up'' in an attempt to drag the latter down into the Darkness. However, in the nick of time, he is able to resist. In the remake, after a stalemate battle, Riku lunges at Lexaeus to finish him off, only to be backhanded into the ''ceiling'' and passing out. Unconscious Riku's body is possessed by Ansem who then kills Lexaeus in ''one hit'' before Mickey appears and frees Riku.

* ''Manga/{{Bleach}}'': Hollow transformations consist of the original personality being largely destroyed in favour of something created from raw instinct. The effect is permanent; even if a hollow can resist the effect (such as Sora), it's only a temporary measure at best. The effect ''does'' lessen as a Hollow goes through its stages of evolution and their personality reverts closer to their original as their never-ending hunger becomes sated (Adjuchas and Vasto Lorde level, as well as becoming an Arrancar), but that takes a long time and a ''lot'' of devoured creatures to get to. And when that happens, there's no guarantee that it'll be the original soul that will be in control. It's possible for any of the other souls that a Hollow has devoured to take over from the inside and become the dominant personality, if it's strong-willed enough. The exception is Ichigo who did eventually learn how to control his hollow power and in the final arc it's revealed [[spoiler: to be the basis for his shinigami power and his zanpakutou's sealed form]].

* ''Manga/FullMetalAlchemist'':

** Averted with [[spoiler: Ling/Greed]], which started off this way but ended up as more a case of SymbioticPossession.

* In ''Manga/{{Psyren}}'' when Amamiya is shot [[spoiler: Abyss, her other personality created from her suppressed emotions takes over momentarily]].

* What happens to [[GoneHorriblyWrong Experiments]] in ''TabletopGame/BleakWorld'' if they get [[EvenEvilHasStandards too inhumane for the voices to stomach]] or are a little to [[PowerAtAPrice liberal with their magic]].

* More of a Split-Personality Removal, but in ''WesternAnimation/TheLEGOMovie'', there's [[TheDragon Bad Cop]], who shares a body with Good Cop, whose face is on the other side of their head. [[spoiler:When Bad Cop refuses to test [[DoomsdayDevice the Kragle]] on his own parents, [[BigBad Lord Business]] decides that Good Cop has made him weak and removes Good Cop's face with nail polish remover and a cotton swab. However, Good Cop's influence isn't completely gone, as Bad Cop later has a HeelFaceTurn and attempts to draw a new Good Cop face on the other side of his head with a marker.]]

* In ''Manga/MobPsycho100'', the main character, Mob, has one of these that takes over in times of great emotional pain.

[[folder:Webcomics]]

* ''Webcomic/{{Homestuck}}'': [[spoiler:Calliope, a sweet and genuinely kind girl, shares a body with Caliborn, a barely restrained sociopath. At the end of Act 6 Act 3, Caliborn becomes not so restrained, escapes from his confines, and starts a session on his own, taking over their body completely and burying Calliope in the process. However, some characters believe that she may not be entirely dead and that in fact finding her might be the key to defeating Lord English once and for all. The author mocks Caliborn for doing this, since he stunted his own CharacterDevelopment by averting the SplitPersonalityMerge that Cherubs normally go through]].

* ComicBook/BettyRoss was in constant risk of this when she was Red She-Hulk.
* The reason Doc Samson turned evil in the ''Red Hulk'' arc; he developed another set of personalities- his current persona, the identity of Doctor Leonard Samson [=PhD=], and the more ruthless 'Samson'- and a 'psychiatric evaluation' in his own mind organised by ComicBook/{{MODOK}} saw Samson kill the other two.
* [[ComicBook/TheIncredibleHulk The Hulk]] himself would like nothing more than to rid himself of "puny" Bruce Banner once and for all, as much as Bruce Banner wants to rid himself of the Hulk. Several iterations have tried, particularly Joe Fixit, and succeeded for extended periods of time, but one way or another Bruce Banner always resurfaces eventually.

* [[VeryLooselyBasedOnATrueStory The VERY heavily fictionalised]] film of "The Boston Strangler" implies something like this at the end. The killer, Albert De Salvo, has been diagnosed with Multiple Personality Disorder (the real life De Salvo was never even suspected of having this condition,) and the film ends with him apparently having gone permanently catatonic after re-enacting one of the murders under the influence of his murderous side, and with no sign of the gentle family man left.

[[quoteright:350:[[ComicBook/Batman https://static.tvtropes.org/pmwiki/pub/images/no_choice4.jpg]]]]

[[quoteright:350:[[ComicBook/TwoFace https://static.tvtropes.org/pmwiki/pub/images/no_choice4.jpg]]]]

%%* The ending of the movie ''Film/{{Identity}}''.

%%* ''Film/FightClub''. Claimed by [[spoiler: Tyler Durden]] to be the evil plan all along.

%% * Phoenix in ''Film/XMenTheLastStand''.

* [[ComicBook/TheIncredibleHulk The Hulk]] himself would like nothing more than to rid himself of "puny" Bruce Banner once and for all, as much as Bruce Banner wants to rid himself of the Hulk. Several iterations have tried, particularly Joe Fixit, and succeeded for extended periods if time. but one way or another Bruce Banner always resurfaces eventually.

[[folder:Pro Wrestling]]

* This was Bloody Mary[=/=]ComicBook/{{Typhoid Mary|MarvelComics}}'s (a villainess most often found in ''ComicBook/{{Daredevil}}'') entire schtick. She had rather impressive psychic and telekinetic powers, but she also had a horrible case of multiple personality disorder; namely, at least nine of them. Two of them (the aforementioned Bloody/Typhoid Marys) tended to take over more often than not, and there have been at least two instances where one or both have "permanently" taken over only for later events to unlock her original (non-powered) personality once more.

* More of a Split-Personality Removal, but in ''WesternAnimation/TheLEGOMovie'', there's Bad Cop, who shares a body with Good Cop, whose face is on the other side of their head. [[spoiler:When Bad Cop refuses to test [[DoomsdayDevice the Kragle]] on his own parents, Lord Business decides that Good Cop has made him weak and removes Good Cop's face with nail polish remover and a cotton swab. However, Good Cop's influence isn't completely gone, as after Bad Cop's HeelFaceTurn, he attempts to draw a new Good Cop face on the other side of his head with a marker.]]