Fallen Heroes

"I did love being a hero. But if this is where it leads... I'm done with it."

- Superman, moments before killing President Lex Luthor which later led to the formation of the Justice Lords.

Fallen Heroes is commonly named for lost heroes and heroines turning on the dark side.

Many heroes walk a thin line between good and evil, indeed many heroes have been driven by despair, rage, or even madness onto the path of evil, often fighting against people they once protected or fought alongside. These villains turn evil due to events in their lives, such as being corrupted by another villain, their desire for revenge, a failed love relationship, or even betrayal. A Hero turned to the Dark side is usually the end-result of a protagonist exposed to a Corrupting Influence, a Brainwasher, a Possessor and occasionally a Charismatic Villain, an Extortionist or a Blackmailer.

Films

 * Andrew Detmer - He had enough of being bullied by the world, so he decided to rebel and manifest his power.
 * Angus Oldfield - His lust for attention coupled with jealously of his brother, damns him when he plays God and messes around with genetics and creates a virus which makes the sheep carnivorous.
 * CLU 2 - He promised that he and Kevin Flynn will change the world together, but Kevin broke his promise to him, which causes him to turn evil and plans to take over the grid and the real world.
 * Darth Vader - Anakin Skywalker was so desperate for the life of his wife, so he decided to betray the Jedi Order to Darth Sidious so he could teach him how to save her.
 * Donald Harris - He gets Infected by the Rage virus, and becomes the leader of the Infected, displaying a sadism none of the others do. Donald tries to kill his children and the other survivors, trying to spread the virus again.
 * Lots-O' Huggin' Bear - He found out that his owner left and replaced him, which lead him to go to Sunnyside and manipulate every toy to turn evil.
 * Scrappy-Doo - He became a villain because he was abandoned by his former friends.
 * Sentinel Prime (Transformers Film Series) - He was originally and formerly an Autobot, but he betrayed the Autobots and sided with the Decepticons so he can save Cybertron.
 * Stinky Pete - After Woody convinced Jesse to go with him back to Andy, Pete decided to stop them by force, he became antagonistic as his arguments no longer worked, he wounded Woody and tried to tear him apart.
 * T-3000 - While Kyle Reese travels back in time to 1984 to protect his mother Sarah Connor, while he was not looking, a soldier named "Alex" a prototype of the T-5000 (a machine) attacks John, starts to infect him and turn him into a machine, also plans to start a war on Judgment Day.
 * Tai Lung - He betrayed his masters and destroyed a village, because he felt his masters did not appreciate his efforts.
 * Theodora - Her sister Evanora tricked her into that Oz is using her.
 * Tighten - He became a villain because he started to think heroes are suckers.
 * Turbo (Wreck-It Ralph) - He ruined a video game out of envy for better quality than his game, later he enslaved and brainwashed inhabitants of another video game.
 * Two-Face (Nolanverse) - He lost his fiance Rachel and half of face, what lead him to betraying his principes, he ceased to believe in justice and followed his vengeance, killing all he believed who are responsible for his tragedy.
 * Vivian (Dawn of the Dead): After a long time of lusting, after Ana when she is skating, Vivian goes to bed dreaming of Ana when suddenly, she and her family is attacked by a zombie - which infects Vivian and destroys her beauty. Transforming Vivian into a murderous psychopath, the zombie plague drives Vivian to kill all her friends, starting with Ana and Luis.
 * Yokai (Big Hero 6) - After something went wrong with Alistair Krei's experiment, Robert Callaghan starts to become wrathful to anyone who tries to stop him from having his revenge, on the loss of his daughter named Abigail.

TV

 * Nightmare Moon - Her envy for sister Celestia made her rebel and become evil.
 * Teridax - He became corrupted because he was unbeknownstly influenced by the Barraki's action, which caused him to plan of overthrowing the Great Spirit, thus becoming a villain which he was now.
 * Hama - She created bloodbending to free herself, but then a decade spent in prison of Fire Nation drove her extremaly vengenful, she enslaved citizens of Fire Nation despite they weren't her opressors
 * SkullGreymon - Greymon was forced to evolve and it turned wrong, he became a bloodthirsty monster
 * Gatomon - She was looking for her partner, the 8th DigiDestined child, but instead Myotismon found her and turned her into his loyal servant.
 * Barriss Offee - She used to be a Jedi before becoming a Sith.
 * Dave (Total Drama) - Chris turned Sky's love interest to dark side after replaying Sky's audition tape.
 * Cherubimon- After he argued with Seraphimon and Ophanimon he became paranoid as he thought they were conspiring against him. His sadness and hatred soon consumed him, what allow Lucemon's dark influence to infect him and made him betray them by rallying beast-type Digimon against them.
 * Zuko - Unlike most of his family he had compassion, but after his own father wounded and exiled him, he became obsessed on finding and capturing avatar no matter the cost.
 * Baatar Jr. - He joined Kuvira as he had enough of living in his father's shade.
 * Delightful Children From Down the Lane - Formerly Sector Z.
 * Diane Simmons - She was fired by Tom Tucker and left by James Woods, then she had become a psychopathic killer.

Literature

 * Sauron (Lord of the Rings) - He became a dark lord due to the corrupting influence of Morgoth.
 * Saruman - He betrayed Middle Earth to Souron believing he has bigger chance for victory.
 * Nazgul- Human kings, who became Sauron's servant, it was easy for him to manipulate them, because their were blinded by their unstillable desire for power.

Games

 * Arthas Menethil- Obsessed on victory he slaughtered population of a city suspecting infection, he took a cursed sword and killed own father to take his place.
 * Illidan Stormrage - He betrayed his brother, because he felt betrayed by him, when his beloved chose his brother over him.
 * Kratos - He became willingly a slave of Ares.
 * Zeus (God of War) - His paranoid fear from Kratos drove him to kill him.
 * Superman (Injustice: Gods Among Us)- After the loss of his loved ones he betrayed his principles, killed The Joker and conquered the world, establishing his dictatorship.
 * Graf Michael Sepperin - He was manipulated by his daughter into believing that the Magi of RKS were targeted by persecution again, and he launched a rebellion to make the world better for Magi and to protect his daughter.
 * Chaos Lord Alteon - After fighting against the Chaos growing within him for years since Drakath attacked and Chaorrupted him, he succumbs to the Chaos and awakens as the 12th Lord of Chaos, and unwillingly murders Princess Brittany and unleashes mayhem and destruction upon his own city through the Chaos Dragon.
 * The Protagonist (Artix Entertainment)- After losing their first fight with Drakath, he Chaorrupts them and turns them into the 13th Lord of Chaos, and they begin destroying different parts of Lore.
 * Fiona (Dragon Age)- Manipulated by Magister Gaeron Alexius she and her fellow mages joined his cult Venatori, she became a conscript and died in battle against the Inquisitor.
 * Illusive Man- He has always been a well-intentioned extremist but his hunger for power and Reaper's indoctrination made him betray humanity and sabotage any attemt to destroy the reapers.

Comics

 * Winter Soldier - Bucky was found and brainwashed by Hydra to be trained as an elite assassin.
 * Ultron - He decided to eradicate humanity after realizing they cannot be saved from themselves.
 * Sasuke Uchiha- He betrayed Konoha and his friends to their sworn enemy Orochimaru tobecome stronger to kill Itachi for slaugther of his family, he fell even further when he joined Akatsuki after learning that Itachi killed his family for Konoha.
 * Nagato/Pain - He wanted to change the world first by words, but after a tragedy, he decided to reform it by wars and genocides.
 * Batman (Frank Miller) - He become more brutal and psychotic due to years spent on fighting against the brutal criminal underworld.
 * Gin Ichimaru - He joined Aizen's conspiracy against Soul Society and betrayed it.
 * Magneto - His hatred to humanity for mistreating him made him declare wars against them.

Creepypasta

 * Gregory Leary- When he uses the magical talisman he is taken back to the city of Delphia, where he betrays his uncle's resistance group, kills Father Lance Madison and becomes the new Grand Magnus of Delphia.
 * Stephanie - she betrays her boyfriend Jack by revealing that she had him marked as her next victim in the Cell Phone Game.

Theatre

 * Macbeth - Originally the king's general and trusted hero, but because of his ambition to become king himself and problems Witches predicted to him, he became a villain.