Batman: I'm going to kill you. Joker: You IDIOT! You made me. Remember? You dropped me into that vat of chemicals. That wasn't easy to get over, and don't think that I didn't try. Batman: I know you didn't.
Superheroes try to rid the world of villains. Unfortunately, sometimes they have the opposite effect.
Maybe The Hero accidentally wronged some Innocent Bystander — say, they or their loved ones were casualties in the collateral damage from a super-battle — and said bystander decides to turn evil to settle the grudge. Alternatively, the character may already be evil, but the Hero's intervention results in the villain gaining superpowers, and a super-grudge to boot.
In a parody or deconstruction of this trope, it might go on to reveal that the actions of the hero were actually irrelevant in terms of the individual's true nature. They were ultimately a disturbed individual who was looking for the first excuse they could find to justify their evil behavior.
Naturally, this is common in comic books. In many cases, however, the villain's origin story isn't even hinted at in their first appearance—it's only after the villain becomes popular that they're given a personal tie to the Hero via Retroactive Continuity.
One of the causes of the Superhero Paradox. See also Disproportionate Retribution, Nice Job Breaking It, Hero. Contrast with Weirdness Magnet, where the Hero doesn't create the villains, but seems to attract them all the same.
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Anime and Manga
Beyond Birthday in the spin-off prequel novel of Death Note was the result of L and Watari’s Tyke Bomb production program.
Inverted in Full Metal Panic!. The last original founder of Amalgam, Mr. Mercury, was so disgusted with what his organization had become that he created Mithril to oppose them.
In Macross Frontier, Word of God states that at least in one continuity (there are several) Ranka lured the Vajra to 117th Fleet just as Grace was getting married, which resulted in Grace's bridegroom being killed, and Grace being mutilated, which turned her into a cyborg, triggering her downward spiral to becoming the Big Bad
First he helped Hanzou capture Konan, which resulted in the death of Yahiko, and Nagato's mental break down.
Then he had Itachi murder the entire Uchiha clan, who however left his brother, Sasuke alive. Guess who had killed Danzo, after the Big Bad revealed this bit of information to him?
Apparently Yakushi Kabuto joined Orochimaru because Danzo had set up him and his adoptive mother -both faithful and competent spies working for him- to murder each other, but Kabuto survived.
A very interesting variant is presented in Bakuman。. It's the unique and slightly dark manga that the main characters wrote that sets the biggest Jerk Ass in the series, Toru Nanamine, on the path to becoming a conniving douche-canoe when he becomes old enough to publish his own manga. For instance, the short that they publish, Money and Intelligence, which takes place in a world where people are ranked based on how smart they are and how much money they have, convinces him to borrow lots of money from his father so he can essentially buy his way to popularity at school, and rely on the advice of people from the internet to revise his manga and give him ideas. Oh, and that last part has the added bonus of completely screwing over his Nice Guy editor.
One could argue that Shampoo is a villainess that Ranma created. Yeah, she would probably be just the same if she had never left her village, but Ranma was the one who humiliated her by eating her prize and then effortlessly beating her in battle, so it's his fault she's in Nerima making a nuisance of herself.
In Digimon The Movie (the dub compilation of the first three OVAs) it's suggested that Willis is the one who created Diaboromon (and the virus that infected him was passed on to Kokomon.)
Inverted in Bleach. One of Aizen's Hollowfication experiments ultimately led to Ichigo's birth. Aizen even went out of his way throughout the series to toughen him up in the hopes of fighting a Worthy Opponent.
Additionally it's also Madoka's fault. Halfway through the movie an Amnesiac God Madoka tells Homura that she would never want to sacrifice herself the way she did in the anime. This causes Homura to believe that Madoka isn't happy in her current position as a Goddess Of Good, which drives Homura into creating a world where Madoka can be happy...even if it means becoming an existence that opposes Madoka.
Dragon Ball GT: The ShadowDragons came into existence because Goku and the Z-Fighters excessively used the Dragon Balls, allowing the negative energy within to accumulate over the years and eventually spawn them.
Inverted in Banana Fish. Big Bad Dino Golzine spent years training Ash Lynx, first as a Sex Slave, then later as the ultimate Cultured Badass. It works too well; when Ash eventually finds the means to take Golzine down, he does so—hard.
The Joker. Many details of Joker's origin vary, but it's widely accepted that the Bat was somehow responsible for the Joker's fall into the vat of chemicals that turned him into the psychopathic clown.
Man-Bat originally doped himself with bat serum extract in hopes of giving himself a bat's sonar — so he could fight crime like his hero, Batman.
It's often suggested that while Batman isn't directly involved their origin, the tendency of his Rogues Gallery to have garish costumes and gimmicks are a reaction to Batman's own. Batman's greatest triumph was to break the mob's hold on Gotham, and his greatest failure was attracting a bunch of psychopathic weirdos to take their place.
This was subverted in the Batman: The Animated Series episode "the trial of Batman"—- where he was put on trial by the Arkham inmates, with the Joker as judge, for the 'crime' of creating them all. In the end, the jury, made entirely of Batman's enemies, couldn't find him guilty of that... they admitted that the trappings or gimmicks might have been different without him, but they were what they were before he even showed up.
One really dark storyline in Gotham Central featured a reporter who killed a bunch of teenage boys and dressed up their bodies to look like Robin solely because he wanted to become a Batman villain.
Pre-Crisis, Lex Luthor was a fan of Superman, then went on to hate his guts after an accident made Luthor lose his precious... hair as well a protoplasmic lifeform he had created and his laboratory. Luthor believed that it was done out of jealousy for Luthor's genius and vowed to prove he was better than Supes. While this seems like Disproportionate Retribution, that same story had Luthor create multiple grandiose engineering projects for Smallville to show Superboy up, only to have all of them go disastrously wrong and forced Clark to intervene. Thus Luthor's hate grew at his warped perception that Superboy was out to publicly humiliate him despite the fact that Superboy had no choice in the matter. Later, in the Silver Age, Luthor gained a more legitimate reason: He blamed Supes for the death of his wife. Nowadays he's often still technically self-created, but it's not exactly Superman's fault: he turned to villainy over jealousy of Superman's achievements.
The jealousy factors into his Silver Age origin as well. The experiment Superboy interrupted was one of a series of increasingly over the top acts of science Luthor was engaging to win respect and admiration that kept getting overshadowed by the Boy of Steel.
The villain Gog gets his start when Superman shatters his illusions about Superman being some messiah, thus causing Gog to see him as the Antichrist.
Bizarro, naturally, since he's an imperfect copy of Superman. Parasite would arguably be less dangerous without Superman to drain for power, and Metallo would at least be much more limited in his activities since Kryptonite is by far the best power source for his robot body.
Post-Crisis, Metallo is created by Professor Vale, who believes Superman is an alien invader, and creates Metallo to defend humanity. In the comics continuity post-Flashpoint, John Corben decides to become Metallo after seeing Superman easily fight his way out of a high secruity military base.
Vale: Are you sure you want to go through with this, John?
John Corben: You saw what happened earlier. We need Steel Solider more than ever, Professor Vale. Someone has to stop Superman... We're going to do what we have to.
Supes also brought the Eradicator to earth (it was a supercomputer from Krypton, he just didn't realize it's purpose would be malevolent.) He threw the Eradicator into the sun, causing the Eradicator to come back as an energy being, then the energy being created a new body for itself based on Superman.
Cyborg Superman. Superman believed that energy being Hank Henshaw could not master Kryptonian technology, so he trapped Henshaw in his birthing matrix. Result: Henshaw used the technology and traces of Superman's DNA to return as a kryptonian cyborg with a grudge.
Eddie Brock's hatred of both Peter Parker and Spider-Man for ruining his life (some people just like to blame someone else) and a chance encounter with the alien symbiote (which had just been "dumped" by Pete and was bitter about it) resulted in the creation of Venom, who would clash with Spidey for decades. Brock's recent Heel-Face Turn came from finally admitting it was his own fault and not Peter's.
The Venom symbiote itself is often portrayed as having been consumed with resentment (and abandonment issues) after Peter rejected it, going on to influence several hosts into lives of villainy and Spiderman harassment.
The original Hobgoblin is an indirect example: he got his start when he was tipped to the location of the Green Goblin's old gear when a minor criminal that Spider-Man allowed to get away stumbled across the stuff.
Green Goblin II/Harry Osborn might also count, as he became a villain to avenge his dad (although one could easily argue that it was his father's actions that truly created the second Green Goblin).
Victor von Doom was Reed Richards' college roommate. Richards corrected one of Doom's experiments; Doom, furious, switched it back to the way it was, then it exploded, scarring Doom's handsome face. Naturally, Doom blamed Richards.
The Mad Thinker's Awesome Android and Modulus are both the result of (mis)applications of Reed Richards's research.
Power Pack'sArch-Enemy, Douglas Carmody (aka the Bogeyman) is a pretty good example of this. While he's pretty villainous when you first see him, he soon tries to hunt down and murder the kids outright, later joining up with the anti-mutant group The Right in hopes of going after them. The reason? The Power Pack blew up the power plant that he thought was going to make him a billion dollars and make him a household name. Okay, so he had no idea that it would blow up the Earth instead...
Black Canary has recently acquired one in Green Arrow/Black Canary. A concert violinist she accidentally deafened through an injudicious use of her canary cry has returned as the sound based supervillain Discord.
Oddly, a Silver AgeJustice League story had musician Anton Allegro become a villain because he'd been accidentally deafened by Green Arrow.
In the United Kingdom's Sonic the Comic, (which was based on the old Mobius/Kintobor backstory that's since been brushed away to line up with the Japanese plot), the story arc loosely based on Sonic CD and Knuckles Chaotix had Sonic going back in time and deliberately causing the accident that turned kindly Dr. Kintobor into Dr. Robotnik. In the altered timeline where the accident never occurred, the Brotherhood of Metallix conquered Mobius and couldn't be stopped- in the real timeline, Robotnik worked on the Metallixes, too, and thought to give them a mass-self-destruct function.
This may have been recycled from a very similar storyline in the earlier British Sonic novels. Robotnik succeeds in taking over Mobius, but Sonic uses Time Travel to stop him ever being transformed from Dr Kintobor, but then a different set of villains steal the Chaos Emeralds in an attempt to infect the Big Bang and therefore the entire universe with Chaos, so Sonic has to stop his earlier self from stopping Robotnik's transformation, as the transformation safely flung the Chaos Emeralds across Mobius out of their reach. In the process, he ends up creating a chaos-infected version of himself called Cinos.
The Transmetropolitan arc "Freeze Me with Your Kiss" features a revenge scheme involving several people wronged in the past by Anti-Hero Spider Jerusalem. Also, part of why the Smiler is elected president is that Spider initially supported him over his similarly corrupt opponent as seemingly the lesser of two evils.
Iron Man villains the Crimson Dynamo and Titanium Man got their start because the Dirty Commies decided they needed their own counterparts to Tony Stark's "bodyguard." Later armored entities such as the Iron Monger and Firepower were created at the behest of Stark's corrupt business rivals, Obidiah Stane and Edwin Cord, respectively. Stane and Cord would both see this trope inverted right back on them, however, as their actions directly led to the birth of a "new" Iron Man each time.
In Stane's case, it was his desire to see Iron Man destroyed, and Stark completely crushed, even though at the time Stark was willing to let Stane be and start anew. Kidnapping Stark's past associates, attacking Iron Man with his "Circuits Breaker" weapon, and then having Stark's new company bombed, killing Morley Erwin in the process, drove Stark to don his newly-completed Silver Centurion armor and fly out to Long Island to confront Stane, forcing the latter to don his still-untested Iron Monger prototype. It didn't end well for Stane, who killed himself rather than see Stark gloat over him.
In the wake of Iron Man's rogue actions during the Armor Wars storyline, the Pentagon commissioned Cord to create Firepower to destroy the renegade Avenger. However, once this was done, Cord refused to turn his new toy over to the Feds (threatening to blackmail them with a press release about Firepower - a heavily-armored suit with a tactical nuke - being designed for riot control), and turned Firepower loose on Stark Enterprises' assets instead. Stark, who'd been willing to leave Iron Man "dead", created a "new" Iron Man that promptly tore Firepower apart.
The Ultimates in the Ultimate Marvel universe were at least partly to blame for the creation of the supervillain group the Liberators, and definitely to blame for the first Hulk rampage through New York.
It ultimately turns out that the advent of the mutant was a direct result of the superhuman arms race.
In Star Wars: Legacy, Obi-Wan Kenobi is inadvertently responsible for A'Sharad Hett's transformation into Darth Krayt. Nice going, Ben.
Hank Pym, the Avenger alternately known as Ant-Man, Giant Man, Goliath, Yellowjacket, Dr. Pym, and the Wasp, built the robot Ultron, which went on to become one of the Avengers' most powerful, persistent, and deadly foes.
Inverted by Ultron himself, who created the Vision and Jocasta, who both became heroes. Ultron kind of sucks at making villains, because he also created Victor Mancha who ended up joining the Runaways
Also played straight to Alkhema, the second wife Ultron created (this one from Mockingbird's brain patterns). Rather than wanting to wipe out humanity all in one go, she wanted to kill them all slowly and painfully, and individually if she could. She even betrayed Ultron to the Avengers.
In the Silver Age, the Reverse-Flash gained access to the secrets of super-speed in the future because Barry Allen placed one of his Flash costumes in a time capsule. More recent continuities have the Reverse-Flash starting as an insane fan of Barry's or, most recently, deriving all of his powers directly from Barry's mere existence, as Barry is now the source of all superspeed.
The Modern Age Reverse-Flash became who he is because of Wally West not helping him. Hunter Zolomon was crippled by Gorilla Grodd and asked Wally to use time travel to prevent the incident. Wally refuses, since this would damage the time stream, and Hunter screws with Wally's cosmic treadmill, and poof, a new Evil Counterpart was born.
Invincible accidentally caused genius multiverse-walker Angstrom Levy's attempt to fuse with all of his alternate selves to backfire, and Levy has become one of Invincible's most determined foes as a result.
Likewise, Powerplex only became a supervillain to avenge himself on Invincible for the death of his sister during one of Invincible's brawls (specifically, Invincible was punched through a building she was inside of, causing it to collapse). Powerplex then killed his wife and infant son by accident while fighting the Nigh Invulnerable hero, fueling further revenge.
Billy Butcher became a cape buster because a superhero raped his wife, and the resulting infant tore its way out of her body. From the audience's point of view he's an Anti-Hero, but in-universe from the supers' perspective he's a villain.
Wee Hughie was a regular socially awkward everyman until his first love interest was smashed into a red paste by a superhero.
Sin City: While The Yellow Bastard was already a bad guy, John Hartigan's attacks led to the Yellow Bastard turning into a disfigured freak, became just a little more unhinged, and it made him take revenge later in life.
Played with then inverted in Les Légendaires, where the protagonist Razzia, who was initially an innocent pacifist kid, became a vengeful barbarian villain as well as The Dragon to Darkhell after his village was seemingly destroyed by the heroic 1000 Wolves Army for no reason. Later however, his dying sister Sheyla reveals him it was Darkhell who destroyed the village and blame the 1000 Wolves for it. Enraged by the betrayal, Razzia turned against Darkhell and joined the Legendaries, becoming part of the sorcerer's worst enemies.
Inverted in a more indirect manner is Red Skull. Namely, the Skull proved to be such a terrifyingly potent propaganda mascot for Nazi Germany that the US decided to counter it by making Steve Rogers Captain America.
Back when she was still in her A God I Am phase (before mellowing out a lot), Luna gave Tirek the Rainbow of Darkness so he could try and prove his love to her. During her and Celestia's reign, Tirek returned to life and ended up having a battle with her for dominion over the night.
Celestia didn't make Discord a monster, but she taught him how to plan and ultimately accidentally helped him discover he was a sadist. She also left him to be punished by his family for helping her bring the Windigos to Equestria, causing him to keep a grudge against her.
Syndrome from The Incredibles. As a boy, his hero-worship led him to try to become Mr Incredible's sidekick, but Mr Incredible brushed him off. Syndrome then decided to get his recognition by designing a robot to kill Mr. I.
That's what Syndrome would want you to think. Actually, he was rejected for incompetence (he screwed up so badly in a fight against Bomb Voyage that Mr. Incredible was lucky to escape). He didn't take it well.
Double subverted in Megamind. Megamind tries to create a new hero to fight, but said person ends up becoming an even worse villain.
Also, Metro Man is partially responsible for turning Megamind into a villain. He knocked Megamind's ship into a prison, causing him to be raised by criminals. He also picked on Megamind in school.
Bowler Hat Guy is actually Lewis' roommate Goob who has grown up hating Lewis because he slept through a baseball game (thus failing to catch the ball where his team would have won if he did) thanks to his losing sleep from Lewis' late-night tinkerings in their room, while Doris has been considered as a failed invention by future-Lewis. The two has then conspired to destroy Lewis' life in Meet the Robinsons.
Films — Live Action
The '89 Batman film had an exchange between Batman and the Joker where the Joker blames Batman for creating him, but Batman replied that years ago the Joker was responsible for killing his parents, creating him.
Batman: I made you, but you made me first.
In any case, the Joker was already an evil mobster before Batman so Batman's role in his creation is limited.
In Batman Forever, Edward Nigma was an employee at Wayne Corp who really looked up to Bruce Wayne. Bruce shutting down Nigma's twisted pet project is what drives him off the deep end, turning him into the Riddler.
Gordon: We start carrying semi-automatics, they buy automatics. We start wearing bullet-proof vests, they buy armor piercing rounds. And you... you're wearing a mask and jumping off rooftops. Batman: And? Gordon: Take this guy...
In The Dark Knight, the Joker invokes this, claiming that Batman's example was what inspired him to change his schtick from clown-themed bank robber to clown-themed avatar of chaos. But considering how much he lies to everyone else, it's probable that he's only saying this to get under Batman's skin.
Joker: Look at me. LOOK AT ME!(speaks to video camera) You see, this is how crazy Batman's made Gotham!
Batman and Gordon created Two-Face in the same movie. Dent warned both of them about the corruption in the Gotham police department but they were more willing to ignore them in lieu of the Joker and finishing off the mob. Gordon's own men ended up working for the mob and kidnapped him and Rachel Dawes, resulting in her death and his disfigurement. In a more cynical example, if Batman had been a few moments late, Dent would've died in an explosion and Two-Face would not have been created. If he had been a few moments early, Dent wouldn't have been disfigured, would not have gone to the hospital, and would not have been driven farther over the edge by Joker. Additionally, if Batman had realized from the start that Joker was lying, he would have saved Rachel, leaving Dent to die.
In the Independent Film Sidekick, Norman (a nerdy comic book fan) discovers that Victor (a sleezy Wall Street Guy he knows) has latent telekinetic abilities. Norman tries to train Victor to develop his powers so he can become a real-life superhero, but (being a Wall Street Guy) Victor eventually decides to use his powers for evil instead, becoming Norman's arch-enemy. A comic book store owner friend of Norman's even remarks (under the false impression that Norman and Victor's story is a pitch for a comic book plot) that, although Norman has failed to make a good hero, it seems he did succeed in creating a killer villain.
In Iron Man 1, Obediah Stane is an evil genius in his own right, but it takes technology stolen from Tony Stark to complete his Iron Monger armor.
In the sequel, Ivan Vanko is inspired to become Whiplash by the revelation that Tony is Iron Man. His real grudge is against Tony's dead father - if Tony had never been born - or had died before the end of the first movie - Vanko may not have engaged in any criminal activity whatsoever. If Vanko didn't know Stark was Iron Man, his revenge probably wouldn't have involved building a suit of armor. Then Vanko improves his energy whips using suggestions from Tony himself. And, Justin Hammer would presumably be a conniving weasel with or without Tony's influence, but if weren't for Stark/Iron Man, he wouldn't have been trying to build suits of armor, or broken Vanko out of jail, or had access to the War Machine armor.
Vanko was already a criminal, though, due to his own father's actions that got him deported with Tony just being the scapegoat for his own miserable existence. Tony does seem to be worried about supervillains being created from his technology and takes steps to prevent this, but Vanko already had the knowledge and genius to make an arc reactor without Tony's help (though the advice he gave did come back to bite him).
This is lampshaded in Iron Man 3: "We create our own demons." Killian apparently became a villain because Tony snubbed him at a party.
In Kick-Ass, Kick-Ass kills Frank d'Amico, causing his son Chris (Red Mist) to become a supervillain
TRON and TRON: Legacy. In the first, hundreds of man-hours worth of programming, spearheaded by Ed Dillinger turned a chess program into something that was going to take over the Pentagon and Kremlin in about a week out of boredom. The second flick was a literal case; Flynn created Clu 2.0 and gave him near-User level of power and a "create the perfect system" directive so he could run things while Flynn was in his own world. Unfortunately, Flynn forgot to install a failsafe or ethics...
In The Assassination of Jesse James by the Coward Robert Ford, Robert idolizes Jesse and believes that he can earn a position of glory at Jesse's side. When Jesse fails to live up to Bob's expectations (and outright mocks him at a few points), Bob decides to instead earn his glory by killing Jesse James. (The entire thing is Black and Grey Morality, but most of the contemporary public views Jesse as a folk hero and Robert as a villain for killing him.)
Inverted in the film Black Scorpion as the the villain of the first film creates the hero by killing her father. Played straight with the mayor in the second film as he ends up turning Dr. Undershaft into Aftershock when his men sabotage her invention. This repeats several times in the series with the mayor's crooked schemes creating several villains. Little wonder most of them want to kill him.
Flashpoint is a tabloid photographer obsessed with discovering Black Scorpion's secret identity who is blinded by her energy ring, but his eyesight was restored by advanced laser surgery, making him one of the heroine's most persistent archenemies.
Looper reveals that during Old Joe's attempt to kill the Rainmaker as a child, the resulting trauma would inspire Cid to become the Rainmaker.
M created the villain of Skyfall when she chose not to rescue him from captivity, forcing him to swallow a cyanide capsule that shredded his insides but didn't kill him. This adds to his Shadow Archetype nature, as the film starts with M risking Bond's life in the course of a mission, and he proceeds to get over the betrayal... eventually.
Loki from Thor has been lied to his entire life, and pushed aside for his older brother, while saving Thor's life many times in the process. All of this escalates, comes to light at exactly the wrong time, and winds up driving him over the edge and into the twisted version of the young man he used to be in The Avengers.
In The Amazing Spider-Man Peter says "I created him" in reference to the Lizard, having given Curt Connors the formula that transformed him into said villain.
Amazing Spider-Man 2 has Peter indirectly create the Green Goblin. When Harry Osborn, his best friend, requests Spider-Man's blood to cure his genetic disease, Peter refuses. This results in Harry injecting himself with the same venom that Peter was injected with when he was bitten by the spider that gave him his powers, which theoretically should work. However, Peter's father encoded the venom to only work with Parker DNA, so Harry turns into the Green Goblin. Worst still, Peter's blood could've worked too.
In Oz: The Great and Powerful, the titular character is partly responsible for turning the naive but good witch Theodora into the Axe Crazy Wicked Witch of the West, who rejects his offer of redemption at the end. While, technically, it was her sister Evanora who turned her evil, Oz's actions (flirting with her like he does with any girl) help push her over the edge.
In Scanners, Dr. Paul Ruth is largely responsible for turning Revok into an evil scanner in the first place. He gave his children psychic powers to begin with by experimenting on his own family with untested drugs, and subsequently abandoned both his children. He let Revok be locked up in an insane asylum rather than help him, causing him to develop a supremacist complex and wanting scanners to rule the world. The plot starts as Ruth tries to use the other child he rejected as a weapon against Revok.
Unbreakable: The Twist Ending reveals this as an inversion. Elijah, aka "Mr. Glass", kills hundreds of people in order to find a real-life superhero, then convince him to follow the call. Also played with, as the supervillain purposefully created himself by becoming a mass murderer criminal mastermind.
In the Star Wars Expanded Universe, the Jedi Order inevitably ends up creating the Sith Order. Each time the Sith are wiped out, some Dark Jedi, recently separated from the Order, finds Holocrons left by a previous Sith Lord and the Order is born anew. The worst part is that this cycle has occurred over half a dozen times.
Ajunta Pall creates what is presumably the original Sith order after being kicked out of the Jedi Order.
Freedon Nadd, having left the Jedi order due to massive ego and rampant paranoia, finds the holocron of one of the old Sith Lords, and resurrects the order.
Ditto for Exar Kun, who finds other Sith Holocrons and resurrects the Sith order.
Revan breaks off from the Jedi to form a new Sith Order - in order to fight the remains of what he calls "the true Sith".
Revan's former Jedi Master, Kreia, leaves the Jedi to find out why he apprentice turned. She makes her own mini Sith order. Ironically, her goal was to destroy the force, as in a fit of Genre Savvy, she saw that as long as the Jedi existed, there would be a Sith order, and that their conflicts would inevitably doom the galaxy. So she sought to eliminate both.
Darth Desolous ditches the Jedi because he thinks the Sith are cooler. Cue mini Sith order on his homeworld.
Darth Ruin leaves the Jedi, starting the order again and begins the New Sith Wars.
At the battle of Ruusan, the Jedi were shoving lightsabers into the hands of small children and sending them to slaughter. They also deemed the native "Bouncers" as too dangerous to keep alive because of the thought bomb. Well, one of those Force Sentitive kids sees her Bouncer friend killed by Jedi right before her horrified eyes. Congratulations! They just created Darth Zannah!
And finally, with Luke Skywalker having destroyed both master and apprentice of the Sith, you'd think it's over no? Well... No. There's a Jedi Purge Survivor that starts a Sith order that would rise to power 100 years later. And Jedi from Skywalker's new Jedi Order jumping ship (one in particular who is even related to him!) Luke has angst about this trope, wondering if he's not training Jedi the right way, but he does try hard; most villains he trained went bad entirely on their own, after they left him. However, there wasBrakiss, who was an Imperial spy who was Becoming the Mask and really starting to trust Luke. Luke trusted him too and thought he'd completely make a Face-Heel Turn, and put him through a test of his spirit just like he'd do to any of his other students... and it was too much for Brakiss to take.
And then there's this little stroke of brilliance from Jedi Apprentice, Obi-Wan and Qui-Gon's backstory series. So, the Jedi council has this problem kid, Xanatos. Too much anger and whatnot. His Master believes in him, but the Council doesn't. And they decide that hey, they're not sure they can trust him, they need to put him to the test. So they send him and his Master to intervene in a conflict where his dad is the Man Behind the Man, and everyone knows it, in the hopes that he'll screw up and they can boot him out. Well as it turns out, the plan works a little too well. Xanatos Face Heel Turns, his Master is forced to kill his father, and he swears bloody revenge on the Temple, going on to become a Corrupt Corporate Executive and Manipulative Bastard out for Jedi blood, who spreads slavery and death wherever he goes, and targets Qui-Gon (his ex-master) and Obi-Wan at every turn. Nice Job Breaking It Heroes.
Inverted in Harry Potter: Dumbledore underlines the fact that Voldemort created his own foe. Villain creating his own hero. Voldemort accidentally shoved a piece of his soul into Harry.
Dumbledore in the backstory, enabled Grindelwald in his exile from Durmstrang, both of them drawing up several plans and ideas to Take Over the World including Grindelwald's Badass Creed, "For the Greater Good" which Dumbledore came up with. This bites him hard and he later tackles Grindelwald on his own.
Sirius Black in the 5th Book is under virtual house arrest in his family home which he hates and is run by a nasty, bitter house elf who parrots the racist ideas of the family which Sirius wanted to run away from. Despite knowing that house elves have Blue and Orange Morality and have to obey their masters, Sirius is indifferent to his plight. This makes Kreacher pass over crucial information to Voldemort, an action which led to Sirius' eventual Mistreatment-Induced Betrayal induced death.
Likewise Barty Crouch Sr. a Knight Templar wizard who allowed wizards to use extreme methods to combat Voldemort was so driven and career focused that he neglected his son who became a Death Eater and later committed Patricide.
In the extended backstory and comments by Word of God, its suggested that James Potter's bullying of Severus Snape only intensified his interest in Dark Arts as an outlet to gain revenge. His arrogance and Underestimating Badassery of Peter Pettigrew also played a part in the latter's betrayal and his eventual death.
Monster Hunter Alpha has this in the third book. Earl bit one of his teammates by mistake while she was pregnant. The resulting child was not only quarter-siren but a werewolf as well, and had a lifelong hatred of the one who forced it upon him.
Very much the case in Animorphs with David, the Sixth Ranger turned Sixth Ranger Traitor. Though introduced from the start as a kid with a bit of an attitude, he at first tries fitting into the team and making the best of things. It's not until he's given the cold shoulder by everyone, forced to sleep in a cold barn and threatened with death by Jake that he decides to betray the team. At that point it's hard to blame him.
In Seven Sorcerers by Caro King, the titular sorcerers are responsible for transforming Arafin Struud from an ordinary human into the Big Bad that he is by first letting him drink from a potion that makes him fully immortal, and then torturing and mutilating him horribly to see just how good the potion works. And then trying to make amends with a simple "Sorry".
Live Action TV
In an episode of Barney Miller, Christopher Lloyd plays a man who blames Captain Miller for ruining his life and turning him to a life of crime after Patrolman Miller stopped him years earlier, making him miss and lose an important job interview. His crime - Littering: Dropping a hotdog wrapper on the ground in Central Park.
The Trio was created because of Buffy. Admittedly, Jonathan (who would have killed himself if it weren't for her, the ungrateful bastard) and Andrew were just in it for the taking over Sunnydale part, but Warren completely was in it for the killing Buffy due to her tracking down the origins of his sexbot April which caused his girlfriend to leave him (what some fans saw as mean, but actually was done in order to save people from his romance and sex slave gone overboard, actually long past his true Moral Event Horizon). Over time he becomes worse and worse, going from jerkass to evil Jerkass to homicidal evil Jerkass to murdering evil Jerkass to his S8 appearance as a genocidal skinless Jerkass.
Warren is both on the creating and created side, really. He attempts to murder Buffy and accidentally kills Tara, sending Willow, one of the most powerful witches in existence, into a Roaring Rampage of Revenge that including Warren being flayed alive. However, Warren survived the skinning due to another witch, Amy, who had turned evil out of jealousy for Willow having so much power without having to work at it (so Amy's another example). Warren then changed his hatred for Buffy into hatred for Willow.
We have Holtz, who wants Angel dead for what he did as Angelus, killing the man's family and forcing him to dust his own daughter.
Angel, having spent 200 years as a psychopathic murderer, has a few of these, usually vampires he sired, who either want revenge, or Angelus back killing. For example, Drusilla (Angelus visited upon her every mental torment he could devise, ending up with...well, a pretty deranged supervillainess, all told), Spike (sired by Drusilla, but Angelus taught him how to be evil), Penn (from Somnambulist) and Sam Lawson (from Why We Fight). James from Heartthrob is a special case - while Angel didn't sire him (at least, it's never said), he tries to kill Angel and Cordelia because Angel stakes his One True Love. There's also Lindsey McDonald, who was introduced as a Amoral Attorney, but for whom Angel makes their battles personal when Angel chops off his hand and the end of Season One.
Spike has created at least one villain: Dana, from the episode "Damage". This one is albeit only indirectly Spike's fault. Dana was kidnapped as a little girl by a human pychopath, implying sexual assault. Later in life, Dana's Slayer visions (allowing her to have psychic dreams and access to the memories of former Slayers) activate. Since Spike has chased around and killed two Slayers he's in a lot of the Slayer memories, leading Dana's damaged mind to substitute him for her actual childhood abuser. When it was all done he even mused in the hypocrisy of trying to tell her "I've done a lot of horrible things, just not to you."
Buffy unknowingly created Angelus, season 2's Big Bad, and he never tired of reminding her about it.
Dollhouse: Has Echo, the main character being an Create Your Own Hero who takes down the people who forced her into becoming a doll. Echo has Bennett, who she accidentally created as Caroline, making a Heroic Sacrificefor her (the aforementioned being made a doll) which was sadly seen as abandonment, causing Bennett to hate Caroline/Echo for abandoning her and making her lose her arm.
Firefly: In a bit of Role Reversal, The Alliance does this, cutting up River Tam's brain, turning her into the insane, psychic, badass 16 year old Phlebotinum Rebel that she became. In other news, Joss Whedon REALLY loves this trope. It's in all of his works.
Harper's Island: Sheriff Charlie Mills turns his wife's obsessive ex-boyfriend John Wakefield into a psychopathic serial killer by having him beaten up and framing him for the attempted murder of a police officer. He serves 17 years of a life sentence for something he didn't do. He kills Sarah Mills as soon as he gets out and Sheriff Mills seven years later, in the present story.
Heroes: In Season 3, it's revealed that Batman-like Anti-Hero Mr. Bennet had a hand in turning nerdy watchmaker Gabriel Grey into the series' archvillain, Sylar. Specifically, Bennet (under orders from The Company) manipulated Gabe into killing again, thus removing the last of his moral inhibitions and completing his transformation into Sylar, who would go on to cause no end of trouble for Bennet and his family.
Also, in Season 2, Hiro's attempts to turn Adam Monroe/Takezo Kensei into a legendary hero (and get busy with Kensei's girlfriend) ends up pushing him from a goofy, drunken mercenary into the season's immortal, Misanthrope SupremeBig Bad.
Not only was Sylar manipulated, he was actually about to hang himself, unable to cope with killing another person for his power.
Merlin: King Uther Pendragon managed to do this to a big part (possibly most) of an ethnicity in his kingdom, when he ordered genocide of all magic users. He's consistently being attacked by magical people as a result, but he always manages to escape punishment and considers the attack evidence that magic is evil. This finally ends in the series 3 finale when his daughter Morgana is revealed to have magic, takes over Camelot with an immortal army, and gives him a "The Reason You Suck" Speech on his treatment of her people. This breaks him completely, and he spends the rest of his life as a fragile shell of his former self.
Sleepy Hollow: So far, all of the Horsemen of the Apocalypse were formerly people Ichabod and Katrina had angered for some reason. Death a.k.a. Abraham van Brunt sold his soul after Katrina broke off her engagement to marry Ichabod, and Ichabod chose the exact worse time to tell him. War a.k.a. Jeremy Crane hates both his parents for abandoning him, but while this is reasonably justified in Katrina's case, Ichabod is blameless since he died before Jeremy was born.
Smallville: While John Corben was actually turned into Metallo by Zod, he already had a hatred for the Red-Blue Blur after one of the criminals saved from a prison bus crash by the Blur murdered his sister.
Half-human/half-wraith hybrid Michael, the series' most frequently recurring villain, was originally created by the Atlantis Expedition in their attempts to create a virus to turn Wraiths into harmless, amnesiac Humans. Michael was quite pissed upon learning he had been manipulated by the team, and very pissed when the team's response to learning that their pet Human-Wraiths were turning back into full-blown Wraiths was to nuke em' all. Before this, there were indications that Michael had standards and would have been willing to work with Atlantis, but too many betrayals turned him into a monster.
And though they didn't create the Wraith and the Replicators, they woke up the Wraith, who'd been dormant, and turned the Replicators into a scourge against humanity. The heroes programmed them to take out the Wraith; they decided the best way was to eliminate their food source -humanity.Brainwashing for the Greater Goodnever works in SGA. The Atlantis crew has a very bad habit of both Moral Dissonance and Nice Job Breaking It, Hero.
The Ancients however created both the Wraith and the Replicators. And then failed to stop either.
Star Trek: Deep Space Nine: If the Cardassians had not immediately started indulging their Nazis IN SPACE tendencies by terrorizing the colonies that wound up in their space as the result of a treaty, the Maquis would never have existed. Proves they're not good at learning, either; they did the same thing to the Bajorans and got the Resistance, from which Major Kira hails.
Xena: Warrior Princess: Xena apparently obliviously did this to Callisto, though this is before Xena's Heel-Face Turn. Callisto believes that until she becomes a goddess and goes back in time to the day her parents were killed. It turns out that the future Callisto was the one who murdered her own parents, but her dazed past self assumed Xena was to blame. Given the chance to undo her past, after an accident she instead made sure it happened, making it clear that one more Never My Fault villain actually is the way she is by choice. She took her mother and her younger self into a barn to protect them. When he father (thinking that the strange woman is one of Xena's Mooks) tries to attack her from behind, she throws a dagger at him without looking. Realizing that she can't change the past, she reluctantly incinerates her own mother with a fireball. In a last-ditch effort, she tries to kill her younger self by setting the barn on fire, but the girl is saved, swearing vengeance against Xena.
A part of the background for Warhammer 40,000 is that the Horus Heresy ultimate erupted because the Emperor consistently mistreated a number of his Primarchs, eventually driving them to rebel against him, which in turn dragged others into joining them. This invocation of Cry for the Devil helps fuel the Black and Gray Morality of the setting.
Lorgar of the Word Bearers, the Arch-Priest of Chaos who was instrumental in turning the others to Chaos, only did so because the Emperor ordered the destruction of a civilization that Lorgar felt was his crowning achievement, and then publically humiliated the devoted and loyal Legion in front of their Ultramarines, calling them the one Legion he was disappointed with and proclaiming every achievement of Lorgar's life was a failure. Making matters worse, he had said nothing about his disapproval of Lorgar's methods for over a century beforehand.
Angron of the World Eaters was a mentally damaged berserker, whom the Emperor forcibly abducted from the ranks of his fellow rebel slaves — the only friends and family he had ever known — and forced to watch die from safety in orbit when Angron refused to voluntarily abandon them. In the Horus Heresy novels, Angron at one point comments he would have turned against the Emperor sooner if his mind had been stabler.
Magnus of the Thousand Sons only turned to Tzeentch for salvation when his attempts to warn the Emperor of Horus's corruption and rebellion lead to the Emperor refusing to head Magnus, instead dubbing him the traitor, and sending the Space Wolves — who hate and despise the Thousand Sons to begin with — to destroy Magnus, his Legion and his whole world.
Actually, the Emperor only wanted to arrest Magnus to have him brought to Terra, however, on the way to Prospero, Horus gave Leman Russ new orders; the Emperor had changed his mind and wanted Prospero and the Thousand Sons destroyed.
It's also implied that Magnus had been in Tzeentch's thrall well before the Emperor found him, and made a further pact with the Chaos God to save his Legion from a mutation curse that probably existed because Magnus was in Tzeentch's thrall. Magnus didn't realize how deep he'd gone until Tzeentch chose to collect during the Battle of Prospero.
Lion El'Jonson's choice to exile Luther, his long-time brother in arms and closest friend, to Caliban during the Heresy admittedly, for a momentary lapse where he considered letting the Lion die for his own glory had a lot to do with Luther's fall to Chaos. Same goes for every other Dark Angel stationed there.
Some endings of Star Fox Command lead to Dash Bowman, initially hoping to join Star Fox, becoming evil in response to choices made by other characters.
This is how Sukhov became Nuclear Winter in Freedom Force. Minuteman was trying to hit him with one of his Minute Missiles, but hit a bunch of liquid nitrogen canisters beside him, covering him with the stuff. This, combined with the latent Energy X in his body, turned him into a An Ice Person with a penchant for stealing atomic bombs.
Inverted in Minuteman's origin story, where he is shot by an American traitor during his meeting with Sukhov. The mortally wounded man crawls to the statue of a minuteman nearby, which has been hit with Energy X and absorbs the energy.
The Licensed Game of Spider-Man 2 combines Mysterio's comicbook and animated series villainous motivations. Quentin Beck tries to publicly discredit Spider-Man, but gets arrested after releasing several criminals into the arena, who subsequently hold the audience hostage. He blames his arrest on Spidey and devises the Mysterio identity (which he tries to pass off as an evil space alien) to get his revenge.
Yomiel strictly speaking got his powers from a freak accident... but he was only in the place where it happened, and unable to notice or react to the meteorite that killed him, because of a standoff with police over a crime he was later exonerated of. He isn't the only one to consider it at least partially the cops' fault; both Cabanela and Jowd consider it My Greatest Failure.
It also features two inversions: Yomiel accidently shot the lead, giving him his ghost powers, and indirectly compelling him to go on the journey that would bring him down, and the foreigners killed Missile, causing him to come back as a relentless ghost.
Disgaea 3: Absence of Justice. Super Hero Aurum, having defeated Mao's Overlord father, found that he had run out of strong, evil opponents. So what does he do? He takes the guise of Mao's butler and heaps loads of mental issues and scewed opinions onto his already strained psyche to make his into an Omnicidal Maniac for him to beat and have a chance of being a hero again.
The Ultima series is notorious for this. The only games in the main series in which the problems the Avatar has to solve are not the direct or indirect result of something he did in a previous game are the first and fourth.
Flay's ending in Mana Khemia gives this a bit of a twist. He wants to become a "Hero of Justice" and drags Vayne along as his sidekick (not that it was hard), but quickly finds that no one seems to need one. Vayne points out the lack of a viable threat, which gives Flay the idea to become one. This, in turn, forces Vayne to become The Hero. It's hard to say who created who.
The Elder Scrolls V: Skyrim has quite a delicious one: You become the villain, potentially. Early on in the game, your Player Character is almost executed by Imperial soldiers due to a clerical error. Thanks to Alduin, you manage to escape. Later, you can join the Stormcloaks, and be the driving force behind kicking the Empire out of Skyrim. You can take this even further if you join the Dark Brotherhood as well, because then you can murder their Emperor as well. What's scary is the fact that this double whammy may effectively lead to the collapse of the Empire. Moral of the story: never fuck with the Dragonborn.
The Stormcloaks can potentially become this to the Thalmor in a blatant case of Gone Horribly Right. Enciting rebellion in a rival empire to weaken them? Classic geopolitical strategy. But what if these rebels go on to win the civil war and form a powerful independent state with (literally) an axe to grind against you? Uh oh.
Even a victorious Empire is bad news for the Thalmor. Their attempts to eradicate Talos worship directly caused a revival in Talos worship all across Tamriel.
Batman: Arkham City: Professor Strange accuses Batman of this, citing the Joker specifically. The Joker also blames Batman for his creation. Played with in that Strange cites the Joker blaming Batman as a case of Never My Fault in that all of his origin stories have him blame Batman, and none of them have him take responsibility.
Hugo Strange: Have you ever considered that all of this is your fault? Your presence creates these animals...
Batman: Arkham Origins takes this further: Batman didn't create the Joker - he gave the Joker a reason to live. Of all the people the Joker had met up to that point, Batman was the only one who wanted the Joker to 'not die'. If he hadn't, Joker would have killed himself and ended his vicious killing spree a LONG time ago. Also, with the introduction of an antithesis, the Joker's schemes and psychosis evolved, to what we know him as, in a matter of minutes.
Ulysses's presence is felt throughout the DLC for Fallout: New Vegas. When the Courier reaches the Divide, he/she can uncover Ulysses's motivation for opposing him/her: the Courier brought a package to the Divide, the settlement that Ulysses had adopted as his new home, which triggered the detonation of the nuclear weapons buried underground. Ulysses, as the only real survivor, held the Courier responsible for the disaster that obliterated his home and his neighbors.
Vengeance Joe from the (sorta-dead) webcomic Van Von Hunter seems to fit. He ended up becoming a minor villain to the title hero when Van didn't introduce himself properly while passing through a town and Joe became insulted, swearing vengeance on him.
In Darths & Droids, Jango Fett is a private detective with a vendetta against Obi-wan Kenobi — because Obi-wan killed his partner, Darth Maul.
In Homestuck, Vriska manipulates events so that Jack Noir get the powers of a First Guardian, turning a powerful but still beatable villain into a near invincible Physical God. The Twist? All this would have happened anyway- Vriska just retconned reality to make herself the centerpiece.
In 8-Bit Theater Sarda definitely qualifies, as the less-than-heroic actions of the Warriors of Light eventually results in Sarda learning how to warp reality and going back into the past to make their lives a living hell. It works both ways, too; Sarda's manipulations helped to make the Light Warriors what they are (three out of the four already had varying degrees of villainous tendencies, but it was Sarda who sent them all over the world, making them stronger and giving them more opportunities to wreak havoc), and thus in a manner of speaking Sarda created himself.
It is heavily implied (and outright stated in the prequel comics) that Captain Hammer's belief that anyone who is nerdy or uncool is a potential supervillain is why Dr. Horrible got to be the way he is. And because you read the above, you know what happens next. And then our hero (Not Captain Hammer, who would barely register as a Nominal Hero) loses his humanity and everything we loved about him.
The villainous speedster Slipstream blames the Global Guardians for the death of his father, the superhero Dogfight (a former member of the Guardians himself) in the 9/11 attacks. Slipstream has sworn vengeance.
In StarCraft Mengsk was responsible for making Kerrigan the Queen of Blades by leaving her to the Zerg.
Fragments of the Tesseract Prophecy from Phaeton seems to indicate that Trayen is destined to turn at least one of his friends against him.
In Noob, Tenshirock and Judge Dead turn out to be the product of the escalation of a Poor Communication Kills situation between a "Well Done, Dad" Guy and his son with Inferiority Superiority Complex. The last straw from the son's point of view was his father doing better than him at the MMORPG in which the story is set, while the father was hoping to gain respect by being good at something his son liked. That lead to the son cutting bridges while leaving the father wondering what the hell happened. The son managed to reach a status higher than his father in regards of the game and was willing to see his father online one last time for an occasion that would let him make sure he never played the game again. The father decided to change in-game identities and go Archnemesis Dad under the new one in hope that it would drive his son away from his new position.
Roland Daggett's attempts to control Matt Hagen with his highly addictive facelift-in-a-jar concoction eventually turned the man into Clayface.
It was Rupert Thorne's attempt to blackmail Harvey Dent that lead to Dent's transformation into Two-Face, the transformation itself lead to Two-Face's extra-legal war on Thorne's criminal organization. Candace, Thorne's right hand, is well aware of this.
Mook: I thought we got rid of this guy. Candace: Are you kidding? We created him.
In "Trial", the Arkham Asylum inmates put Batman on trial, accusing him of creating them. This trial leads to the revelation that even if Batman had not pushed them off the edge, they were all deeply disturbed people and would have entered villainy anyway from their own motivations. In fact, they created him. The villains then come to terms with this and find Batman innocent... and then, because they are such bad guys, they try to kill him anyway.
In "Lock-Up", the eponymous villain was formerly a guard at Arkham Asylum who got his position due to endorsement and support from Wayne Enterprises. When he goes insane and begins kidnapping the people he blames for the cities problems (The police, bureaucrats and reporters that he says cause the criminals) Robin snarkily comments "Another fine villain brought to you by the Wayne Foundation." The look Batman shoots him is not happy.
An inversion occurs in "Beware the Creeper": A villain (the Joker) creates his own hero (the Creeper). And he even does it referencing the way he claims Batman created him, throwing someone into a chemical vat:
In the episode "Over the Edge", the plot is set by Batgirl's fear that this trope will enact if she would be a casualty of the collateral damage from a super-battle: The Commissioner Gordon would become a Knight Templar Parent that will destroy the Bat-family, being created by the death of heroine Batgirl.
Terry did not create the Corrupt Corporate Executive Derek Powers, but he was responsible for his mutation into Blight. Powers flat-out admits he'd killed others besides Terry's father. Because of what Powers did, Terry feels no sympathy or regret for the man.
Terry: You mean... I made him that?
Bruce: You may have... in part.
Terry: ...Good. (Bruce gives him a stern look) Hey, this guy had my father murdered and all he's done since is hide from the law. Well, no more hiding for Mr. Derek Powers. Now everyone can see what he is. Even in the dark.
A lesser example is with Shriek, who was pressured into using his sonic weapons to kill Bruce Wayne by Derek Powers. While at first he "only" intended to murder Bruce, and that only to secure more funding for his research, once Batman causes him to go deaf during their battle he went insane and became a full-fledge supervillain with the sole goal of getting revenge on Batman. Shriek did have initial problems, since he was trying to commit murder for monetary gain.
Powers actually did the inverse and recreated Batman since his attempts to cover up his abuses brought Terry and Bruce together.
Inverted: Plastic Man was a henchman and thief until he was Cursed with Awesome as a result of Batman's actions. Batman personally sees to Plas' reform and rehabilitation; now, larceny-related issues aside, Plastic Man is a genuine superhero thanks to Batman's influence.
Another inversion (a villain creates a hero) is from "Chill of the Night!" Batman confronts Joe Chill (the man who murdered his parents) during a weapons auction, where many of his Rogues Gallery are in attendance. In the fight, Batman reveals to Chill that he's Bruce Wayne. Chill realizes that by killing Thomas and Martha Wayne, he inspired Bruce to fight crime. He's the reason Batman exists. In a panic, Chill admits this to the Rogues. They aren't amused (except for Joker; he thinks it's hilarious).
Parodied when Timmy becomes The Masked Magician. The Crimson Chin warns Timmy about creating his own supervillain, and lo and behold... The Hanker-Chief!
Crimson Chin is speaking from experience: His archenemy, the Bronze Kneecap ("and his big BRONZE KNEECAP!!!"), turns evil when, in a parody of supervillain origins, the Chin accidentally breaks his leg during a jai alai tournament, causing him to get second third place once again, and then doesn't apologize. And so Ron Hambone melted down all his third-place bronze trophies...
And in another episode when Timmy wished for a world of superheroes, he accidently created super-villains as well.
In Transformers Animated, Cyrus "The Colossus" Rhodes hates the Autobots apparently because he lost his job to a machine, and Prometheus Black has a gripe against Sumdac because Sumdac Systems gets all the lucrative contracts instead of him. Interestingly, before Black became Meltdown, he was receiving funding from a member of Sumdac Systems' board of directors.
Blackarachnia in the same series might count definitely counts, as she allied herself with the Decepticons after Optimus and Sentinel abandoned her on Archa 7, a spider planet, believing she was dead.
Sentinel also came to hate Optimus after the very same incident, sparking an intensely antagonistic relationship between the two.
Wasp was falsely implicated as being a Decepticon spy and during his time in the stockade went nuts and wants a lot of revenge on Bumblebee. Though, Wasp wasn't a very nice bot to begin with.
Probably as a parody to the Fantastic Four example above, Vlad, Maddie and Jack are working on their first Ghost Portal. Jack pours diet soda into a crucial part, and it blows up in Vlad's face, giving him Ecto-Acne, and with it, his ghost powers. Then he goes all evil and revengey.
Technus, though in a more Lamp Shading and humorous way. Danny unintentionally frees him from the Ghost Portal (or something) when he first meets him. Assuming him to be a villain, Danny tells him he will not take over the world. Technus, confused, then enlightened actually takes his advice, thus setting his path of villainy.
There's an episode that toy with this, as a bystander who appeared in many prior episodes plots to get his revenge on the gargoyles and relates every previous encounter he had with them. Played for comic relief, as his revenge was merely a pie-shooting bazooka. For the record, the gargoyles inadvertently cost him every job he ever had since 1997. And the pie was banana creme. The gargoyles, including Goliath, who took the pie, has no idea who he is. Or why he did it.
David Xanatos created Thailog, a clone of Goliath educated with Xanatos' own worldview. Naturally, Thailog turned on everybody.
The Hunters were created when Demona slashed the face of a farm boy. Said farm boy then dedicated his life to hunting down every last gargoyle in existence. And when he died, his moniker was adopted by another who created generations of families whose whole life is killing Demona and gargoyles.
Darkwing Duck accidently causes Bud Flood to fall into a vat of contaminated water, turning him into the Liquidator. It soundsawfullyfamiliar... Flood had contaminated the water himself, and Darkwing was in fact there to stop him from doing exactly that; so, really, The Liquidator created himself, Darkwing just helped.
Ben 10's Evil Counterpart Kevin 11 was just a emo New York City street kid with the superpower of absorbing and channeling energy, until Ben teamed up with him to go on a criminal joyride, allowing Kevin to absorb the Omnitrix's energy and gain all of Ben's superpowers. Already selfish and mean-spirited, access to all that power quickly turns Kevin into a full-blown Psycho for Hire who goes on a nation-wide crime spree and attempts to kill Ben on multiple occasions. He got better. Mostly.
Mojo Jojo was originally created by Professor Utonium, and worked as his assistant. The professor and the girls indirectly turned him into a villain by making him jealous, as the girls hogged the spotlight, leaving Mojo in the shade; which eventually drove him out into the street. As an added twist, Mojo was himself responsible for Chemical X being added into the concoction that spawned the girls. Apparently, he was a very bad lab assistant from the start.
According to one episode, Mojo's traveling back in time to try to eliminate Professor Utonium as a child and being thwarted by the girls is what inspired Professor Utonium to become a scientist in the first place. Bringing the whole thing full circle...
An episode of The Simpsons featured the heroes not so much creating a villain as recreating one. While in Italy the Simpsons run into an apparently reformed Sideshow Bob living happily and honestly as the mayor of a small town. Bob isn't exactly delighted to have the Simpsons around but he treats them well enough... until Lisa gets drunk and 'outs' Bob as a former criminal. His new life destroyed he promptly swears revenge.
Spider-Man created Mysterio: He exposed special effects man Quentin Beck as the one responsible for a helicopter getting damaged during the shooting of a film, and Beck invented the Mysterio identity upon getting out of jail to take revenge.
Mysterio: It's payback time! Spider-Man: Payback? For what? You did it all to yourself. Mysterio: That's what my psychiatrist said, but you know what? His sessions never made me feel this good!
In "The Sting of the Scorpion," Jonah has hired PI Mac Gargan to trail Peter to figure out how he gets all those great pictures of Spider-Man. After finding out, Spider-Man bursts into the Daily Bugle and purposefully plays tough to try to scare some sense into them - even webbing Gargan to the wall, humiliating him. Unfortunately, all he did was give Jonah motivation to bankroll a Neogenic experiment and a willing test subject - making Mac Gargan the Scorpion.
And like in the comics, Venom - with the symbiote being rejected (and nearly killed), while Eddie Brock had been fired from the Daily Bugle and repeatedly humiliated.
In The Batman Mr Freeze considers Batman responsible for making him what he is now. However as Victor Fries he was already a criminal to begin with, had not been for that cryo accident he would have been just some common crook.
The VeggieTales episode "Larry-Boy and the Rumor Weed" actually begins with the title superhero accidentally creating the title weed by knocking a plant off a building and onto some power lines.
Doc Venture in The Venture Bros. has a singular talent for this. Baron Ünderbheit became his enemy after an unspecified lab experiment blew off his jaw, The Monarch—probably justifiably—blames him for some college Noodle Incident that ruined his life, and Richard Impossible lost his mind after his wife tried to leave him for Rusty.
All ultimately not Rusty's fault. The Monarch was responsible for blowing off Ünderbheit's jaw, and was himself already a lunatic in college for reasons we still don't know. Possibly for being raised by Monarch Butterflies for a period of time after surviving a plane crash which killed his parents as a child. Richard Impossible didn't snap until his wife left him for Rusty's brother. Doc Venture just happens to be a hate sink for supervillains.
In The Avengers: Earth's Mightiest Heroes, Tony Stark "creates" the villainous Energy Being Wonder Man. When Simon Williams' company goes under because of Tony Stark, Simon is prompted by his brother (Grim Reaper, an agent of H.Y.D.R.A.) to volunteer for an experiment conducted by MODOK to gain the power he needs to take his revenge. Tony was actually trying to help him by employing him, but he didn't get around to actually saying this to him.
In Teenage Mutant Ninja Turtles (2012), the Turtles accidentally cause Snake's mutation by sending a van smashing into the front of the Kraang's lair as a distraction (so that they could sneak in). In the crash some Mutagen that was in the back of the van gets splattered over Snake, thus mutating him into Snakeweed.
Justice League presents the darkest inversion of this trope in "Epilogue", where Well-Intentioned Extremist Amanda Waller reveals to Terry McGinnis that when she noticed Bruce Wayne was getting too old to be The Batman, she decided to create her own hero by collecting Batman's DNA, finding a couple with an identical psychological make-up as Thomas and Martha Wayne, overwrite the husband's reproductive DNA with Batman's without the man's knowledge, with Terry being the resultant child. Then when he was 7 years old, Waller commissioned the Phantasm to assassinate Terry's parents in his presence. Thankfully, the Phantasm decided to abort the operation to honor Bruce's legacy, instead of taint it.