History ProtagonistJourneyToVillain / VideoGames

* In ''VideoGame/SpecOpsTheLine'' this happens to both [[spoiler:Col. John Konrad and Capt. Martin Walker]]. They both came to Dubai hoping to help but [[spoiler:Konrad and his 33rd battalion ended up committing ever greater atrocities on the inhabitants of Dubai under the pretense of maintaining order while they evacuate the city, which eventually led Konrad to commit suicide once he realized what he had done. Walker and his Delta squad came to look for the remnants of the 33rd but ended up killing every single one of them and most of the locals. In one of the endings, the events of the game have driven Walker so deep into insanity that he massacres the US army rescue party that came looking for him. In another, he has a belated HeelRealization and kills himself. Or Walker can have that belated HeelRealization... then defy the trope in another ending and decided to live and go home, facing and attempting to pay for his crimes even at cost of becoming a broken ShellShockedVeteran.]]

* ''VideoGame/CryOfFear'' does a twist on this trope, where [[spoiler:it's revealed that the Simon you're playing as is a projection of himself in his therapy journal. Depending on the ending this either applies to the real Simon (who [[MurderSuicide kills the girl he has a crush on and/or his therapist and then himself]] in the bad endings) or Book Simon (who becomes a bloody monster [[HeWhoFightsMonsters like the ones fought throughout the game]] and has to be defeated for Simon to start truly healing his mental health).]]

* ''VideoGame/CryOfFear'' does a twist on this trope, where [[spoiler:it's revealed that the Simon you're playing as is a projection of himself in his therapy journal. By the end, the Simon we are playing as is an EnemyWithout of the real one [[HeWhoFightsMonsters no different from the psychos he's killed]].]]

** ''Phantom Pain'' alone is fueled on this trope as a figurative interpretation of one of the more canonical story interpretations. The game has a hidden "point" system where the player is assessed as more evil for doing certain deeds, some of which are crucial to the plot. But if a player goes all in, the shrapnel in Snake's head becomes a devil horn, and he becomes stained in the red blood of allies he has betrayed and enemies he has needlessly killed. By the end of the game, Snake looks in the mirror, and [[spoiler: disgusted by what he sees, shatters it. As he walks away, turning his back on the man he once was, his organization's emblem on his shoulder has changed from the Diamond Dogs one he had throughout the game, to the Outer Heaven one from the game in which he is the villain.]]

* ''VideoGame/Borderlands'':
** This is pretty much the context for ''VideoGame/BorderlandsThePreSequel''. Here, Handsome Jack, previous BigBad of ''VideoGame/{{Borderlands 2}}'', is shown as a small-time Hyperion manager trying to save millions of lives from [[WellIntentionedExtremist Zarpedon]]. At one point he even laments that innocent people are suffering because of Hyperion's war with Dahl's Lost Legion, stating that having problems with Hyperion is one thing, but the people on the moon don't deserve to suffer. The player gets to watch Jack slowly descend into the amoral, self-centered, enormously unethical and downright villainous behavior that we get to see by the time of ''Borderlands 2''.

* Basically, the whole point of ''VideoGame/FarCry3''. In the end, [[spoiler: it's up to you to decide whether Jason Brody is redeemable or not; - in almost comical defiance of the page quote above, if he chooses to stay on the island and embraces its warrior-culture, he dies a villain. However, if he chooses to leave with his friends, he lives as an incredibly traumatized yet redeemable hero.]]

* An interesting example happens in ''VideoGame/{{Harvester}}''. While Steve has the option of going around and killing the entire town, [[spoiler:the ending reveals that the entire town of Harvester is a literal MurderSimulator trying to turn Steve into a SerialKiller]]. The player has the option of playing this trope straight or defy it.

* In ''VideoGame/LiveALive'', the penultimate chapter turns out to be a condensed version to fit with the "short story anthology" nature of the game's plot structure. As it turns out, it's actually detailing the BigBad's StartOfDarkness and tying all the previous, heretofore seemingly-unrelated short stories together. The chapter's focal character is Oersted, once a hero to his kingdom. Oersted is tricked into killing the king, which sees him branded a traitor and outcast, and he's even believed by many to be the demon king. To make matters worse, it's revealed that his best friend, Streibough, orchestrated the whole ordeal [[GreenEyedMonster to get revenge for Oersted always delegating him second-fiddle]]. To top things off, after having been [[EtTuBrute betrayed by his former friend and adventuring companion]], Princess Alethea, the woman he was in love with, was DrivenToSuicide by Streibough's death at Oersted's hand, having fallen in love with ''him'' instead. After losing everyone and everything dear to him, [[HeroicMime Oersted]] [[SuddenlySpeaking says]] that, if people already believe him to be the Lord of Dark, [[ThenLetMeBeEvil he might as well be one]], and so he becomes the [[BigBad Lord of Dark, Odio]].
* ''VideoGame/AssassinsCreedRogue'' details the journey of Colonial Assassin initiate Shay Patrick Cormac from a member of that order to becoming disillusioned with it [[spoiler: after attempting to reclaim a Precursor artifact causes a massive earthquake that devastates the city of Lisbon]] and leaving it rather violently, ending up a member of the [[KnightTemplar Templars]], [[spoiler: becoming responsible for the devastated state of the Assassin Brotherhood at the beginning of ''III'' and killing Adewale from ''Black Flag''.]]
* This is pretty much the context for ''VideoGame/BorderlandsThePreSequel''. Here, Handsome Jack, previous BigBad of ''VideoGame/{{Borderlands 2}}'', is shown as a small-time Hyperion manager trying to save millions of lives from [[WellIntentionedExtremist Zarpedon]]. At one point he even laments that innocent people are suffering because of Hyperion's war with Dahl's Lost Legion, stating that having problems with Hyperion is one thing, but the people on the moon don't deserve to suffer. The player gets to watch Jack slowly descend into the amoral, self-centered, enormously unethical and downright villainous behavior that we get to see by the time of ''Borderlands 2''.
** Unlike most cases, though, it's ambiguous if Jack is [[CharacterDevelopment becoming a worse person]], or just [[ManipulativeBastard taking advantage of the situation]] to get enough power that he doesn't need to [[WhatYouAreInTheDark hide who he is anymore]]. There's also the fact that at this stage he has already [[spoiler: enslaved his own daughter, used the remains of a dimensional beast to secretly create a WaveMotionGun and pretty much kickstarted all of this to claim the contents of a Vault for himself alone]].
** ''VideoGame/{{Borderlands 3}}'' [[spoiler:confirms that he was always an asshole (because of his grandmother's abuse), but he used to be a high-functioning asshole and a loving father, until his life was ruined when a bandit kidnapped his daughter, and when she used her powers in self defense, she accidentally burned her (mute) mother to death. From there, it kind of snowballed as Jack kept his daughter imprisoned so she couldn't turn siren-psycho, only to eventually turn psycho himself. For extra ambiguity, it turns out that Tyreen's father did the opposite of what Handsome Jack did to Angel, teaching her about all the fun vault-hunting adventures she would have with her powers once she became an adult]]. [[EntitledBitch That didn't turn out well.]]
* In ''[[VideoGame/{{Ravenmark}} Ravenmark: Scourge of Estellion]]'', [[spoiler:Livia Cassianus]] is a good person trying to serve [[spoiler:her]] country. Over the course of the campaign, [[spoiler:she]] falls in love and grows to accept [[spoiler:her]] new role as the UnexpectedSuccessor. However, [[spoiler:her lover's HeroicSacrifice at the end drives her over the edge, resulting in Livia becoming the ruthless Scarlet Empress]] by the time the sequel rolls around, in large part responsible for the sorry state of the Empire.
* Taking the non-canon path in both ''VideoGame/KnightsOfTheOldRepublic'' games will be this for the PC.
* As with the ''Knights of the Old Republic'' example above, taking the Dark Side paths in the VideoGame/DarkForcesSaga games ''VideoGame/JediKnightDarkForcesII'' and ''VideoGame/JediKnightJediAcademy'' will turn the games' storylines into this for their respective player characters. This is particularly true of ''Jedi Knight'', where Kyle's descent into darkness is determined by the totality of the player's actions throughout the game - slaughtering noncombatants, delving too much into Dark Side powers, etc. - whereas ''Jedi Academy'' presents players with a single, discrete choice to go light or dark.
* This trope applies to both ''VideoGame/{{Nier}}'' and ''VideoGame/NierAutomata''. In the first, Nier only sees the [[TheHeartless shades]] as [[AxCrazy mindless killing machines]], and he's right [[spoiler:at first, about the ones near his village that were exiled for their violent degeneration. Then he invades a shade stronghold to find his daughter/sister, and the peaceful shades, unable to communicate, are forced to defend themselves when he assumes they are a threat. This cycle of assumption and revenge escalates until he has committed genocide against the shades and killed a living CosmicKeystone, dooming both shades and [[TomatoInTheMirror "humans"]] to extinction.]] In ''Automata'' [[spoiler:9S passes the DespairEventHorizon after realizing that the Machine War is not only pointless but that Yorha was created to [[ForeverWar keep the war going]] [[YouHaveOutlivedYourUsefulness and then be disposed of]]. Grief-stricken after [[TheHeroDies the death of 2B]], he decides to get revenge on A2 and destroy humanity's remaining data to "solve everything".]]
* ''VideoGame/FallenHero'' has you play as the former hero Sidestep, who's on their inexorable way to a villainous career, but [[WellIntentionedExtremist just]] [[WoobieDestroyerOfWorlds how]] [[BloodKnight far]] you fall is entirely up to you.
* ''VideoGame/TotalWarWarhammerIII'' has Prince Yuri Barkov of Kislev, who you play as in the tutorial campaign. At first a heroic and beloved prince of Kislev, he sets out to learn why the bear god Ursun hasn't ended Kislev's winter with his roar. In the course of his campaigns, he learns it's because the Daemons have captured and are slowly killing Ursun, and sets out to free him, in the process however, he starts to take more callous and cruel actions, as well as becoming more vicious and abrasive towards his men in pursuit of his goal. By the end of the final tutorial mission, Yuri has turned into a vicious monster himself who doesn't hesitant to kill his own beloved brother and offer his skull to a Daemon of Khorne to bridge the way to Ursun's prison, and when confronted with the bound Ursun, he's so far gone that [[MagnificentBastard Bela'kor's]] words convince him Ursun is to blame for all of his misfortune and he shoots Ursun with a chaos-tainted bullet, mortally wounding him. After doing that and being blasted away by Ursun in retaliation, the dying Yuri calls out to the chaos gods for more power and they grant it to him, transforming him into the Chaos Undivided champion known by his title of God-Slayer.