History Main / EvilFormerFriend

* Two examples from the ''Franchise/SlyCooper'' series:

* In ''VideoGame/FinalFantasyXIV'', there's [[spoiler:Ilberd]]. Once, he was Raubahn's best friend, both of whom longed to see Ala Mhigo freed from Garlean rule. When Raubahn soon became Nanamo's right hand man, he saw it as a terrible betrayal. He became one of the big leaders of the Crystal Braves when Alphinaud was forming the group and ultimately [[spoiler:lead its betrayal, framing the Scions of the Seventh Dawn with Nanamo's supposed death. He would go on to do a LOT more horrible stuff later on.]]

* In ''Anime/DragonBall'', Master Roshi, Goku and Krillin's mentor, turns out to have been a fellow pupil of the Crane Hermit, mentor of Chiaotzu and Tien Shinhan, who are Goku, Krillin, and Yamcha's main rivals in the World Tournament (although both of them eventually make {{Heel Face Turn}}s); most of the two hermits' interactions consist of them taking potshots at each other. The following story arc reveals that they trained under the same master, Master Mutaito, and that the Crane Hermit turned to evil after Mutatito died sealing away the Demon King Piccolo.

** Toa Nidhiki, not that you'd know it by his current insectoid appearance. He tried to sell out the Toa to the Dark Hunters in return for being put in charge of the conquered city, but Lhiikan overheard him making the plans and set a trap of his own, and forced Nidhiki to leave with the defeated Hunters. When he tried to betray ''them'', The Shadowed One hired [[FemmeFatale Roodaka]] to use her powers to transform him into his current state ([[AndIMustScream the irony being that]] [[IronicHell he's ''terrified'' of insects]]).

* Ryo Asuka, protagonist Akira Fudo's best friend since childhood, turns out to be this in ''Manga/Devilman''. [[spoiler: Near the end he is revealed to be the reincarnation of the Devil himself,]] responsible for throwing mankind into chaos and self-destruction with his reveal of the existence of demons among humans.
** The finale subverts this trope, however, in the aftermath of Akira and Ryo[[spoiler:/Satan's]] final battle.

* The usual dynamic is flipped in ''WesternAnimation/SheRaAndThePrincessesOfPower'', as when [[TykeBomb up and coming Horde officer]] Adora [[HeelFaceTurn throws in her lot]] with the Princess Rebellion her bunkmate and closest [[LesYay friend]] Catra finds herself in conflict on several levels.

* The music of Music/TheMegas, being based on the "VideoGame/MegaMan" series, retains this dynamic between Doctor Light and Doctor Wily, and it's made the war they've found themselves waging against each other deeply personal in a way that takes a heavy toll not only on the two of them, but on Mega Man and Proto Man as well.

* Dr. Light and Dr. Wily had this relationship in ''VideoGame/MegaMan''.

* 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.

* ComicBook/LadyShiva was once a good friend of ComicBook/RichardDragon and ComicBook/BronzeTiger before her BloodKnight tendencies, ambition and her sister's death turned her already morally questionable search for a WorthyOpponent into her entire raison d'etre. When she runs into the two of them these days she still talks like a friend, while trying to fight Dragon to the death and condescendingly ignoring or sending mooks to kill Tiger.

* ''Manga/SoulEater'''s [[TheGrimReaper Shinigami]] and [[HumanoidAbomination Asura]].

* Two examples from the ''VideoGame/SlyCooper'' series:

* Athos and Nergal from ''VideoGame/FireEmblem''.

* The music of Music/TheMegas, being based on the "VideoGame/MegaMan" series, retains this dynamic between Doctor Light and Doctor Wily, and it's made the war they've found themselves waging against each other very personal.

* Dwayne Carter is this to Colby on ''Series/NUMB3RS'', though this is subverted later when it's revealed that [[spoiler: Colby ''knew'' Dwayne was crooked, but played the trope because [[ReverseMole he was actually using Carter's reliance on ''him'' to expose Carter's boss]] and he needed to maintain his cover with Carter in order to avoid blowing the operation.]]

* ''Film/XMen'':

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. See WeUsedToBeFriend when characters are friends but then something breaks them apart.