So, the heroes have finally captured Duke Diabolico, yay! ... so now what? He's repeatedly proven he not only doesn't want to reform, but will turn any such attempts into another dastardly scheme by masquerading as reformed, and the Cardboard Prison is looking especially porous right now. Plus, he's proven smart enough to defy being a Self-Disposing Villain. The heroes couldn't just kill him, and even if they weren't too principled against killing, he's also avoided giving the heroes (and other villains) reasons to kill him.
There's another option: to do a Brainwashing ... for the greater good! The way it is done can have varying degrees of squick. Heroes might go the "soft" route and administer Care Bear Stares, use The Power of Love and Friendship, and in conjunction with "motivational" speeches trigger a quasi-voluntary HeelFace Turn. However, a more extreme villain might require a more extreme method, and perhaps a shot of Laser-Guided Amnesia, a Restraining Bolt, or even a new personality may be in order, or even a Mind Rape to screw him thoroughly. And Voilà! Duke Diabolico, the most evil and theatrical supervillain to grace the Saturday weekend is now a good-hearted codger. Who cares about Mind over Manners, right?
Naturally, this trope involves Grey and Gray or Black-and-Gray Morality at best, because like any brainwashing, it involves compromising the free will of the brainwashee. If done by the heroes, they are probably also running on Black-and-Gray Morality or Grey-and-Gray Morality, otherwise there is probably some serious Values Dissonance going on in the work. If The Antagonist is doing the brainwashing, then it is treated as any regular ol'e Brainwashing, and expect them to be a Lawful Evil character of the Well-Intentioned Extremist or Knight Templar variety justifying it through The Evils of Free Will. If brainwashing is policy, there is also the danger of Jumping Off the Slippery Slope until litterers are brainwashed into creepy all-loving paragons because Utopia Justifies the Means.
The brainwashing has a tendency to be flimsy though, and when it slips the results are often pretty messy. Duke Diabolico may have been helping an old lady cross a street when he just spontaneously relapses and throws her under a semi. His minions or allies may come by and break the brainwashing for him. He still might find himself liking good more than evil and do a HeelFace Turn on his own accord. He might face a Heroic BSoD as he grapples with a hidden lifetime of evil. but if he doesn't, Oh, Crap!.
The brainwashing doesn't have to specifically be done to change one's moral inclinations; upholding the Masquerade is an example of this. If Muggles were to stumble on the existence of the Masquerade and The Masqueraders have the ethical sense to not erase them from existence, then some Laser-Guided Amnesia is in order to keep them oblivious. Of course, being Muggles, the ethics of this isn't discussed much. This applies especially when it is justified that The World Is Not Ready for the masquerade to be broken, or that it is for their own good.
- In Danganronpa 3: The End of Hope's Peak High School, this is Kazuo Tengan's ultimate plan to eradicate Despair and end the Tragedy for good by using Ryota Mitarai as a pawn, exploiting his talent in order to brainwash the entire world with Hope. Note the difference between this plot and the Neo World Program in Danganronpa 2: Goodbye Despair: in the latter, the Neo World Program merely removed existing brainwashing and memories but requires its participants to actively pursue their idea of hope. In the former, Mitarai's video removes entire human natures, and (much like the brainwashing that corrupted Ultimate Despair in the first place) gives them no choice in the matter.
- In Fairy Tail, it's revealed this was the original reason for existence of the superweapon Nirvana. The Nirvits sought to use it to bring peace to the world by reversing the moralities of warring nations to make peace. It worked out for a time, but what the Nirvits didn't realize was happening was the "darkness" of all those they reversed was being reflected onto themselves until they fell into a war of their own that wiped them out. The last surviving Nirvit realized how foolish they had been to try and forcibly change others "for the greater good" and sealed Nirvana away, his spirit enduring to watch over the site for centuries as atonement until Nirvana is ultimately destroyed in the present.
- In Himenospia, Himeno gains a wasp-like stinger that works as a Love Potion on the females she stings, and uses it on her abusive mother and her bullies. Her "soldiers" don't lose much autonomy and are made aware of their own flaws, becoming strong-willed and generally kinder as a result. After surviving the massacre of her classmates by the police when they find out about the wasp-girls, Himeno manages to gain enough political influence from stinging women related to the media and the government to turn her hometown into a sort of Feminist Fantasy.
- This is Tobi's and Madara's main goal entitled "The Moon's Eye Plan". They plan to cast a permanent genjutsu on the moon in order to сapture all people in eternal genjutsu and collect all the chakra in all people in order to reach peace in the world, since they believes mankind cannot live peacefully of their own free will. Unfortunately, this is also Kaguya Otsutsuki's plan as well. She too will brainwash the human populace into obeying her while also turning a vast majority of them into White Zetsu soldiers, depriving them of their individuality. She did this before in order to prepare herself for a battle against her own clan and now she wants to add more to her army.
- This is Itachi's backup plan for Sasuke. To make a long story short, he acquired a specialized Sharingan capable of rewriting Sasuke's mind to be loyal to Konoha in the event he completely betrayed the village. He stored it with Naruto, where it was eventually used to break Kabuto's control over the resurrected Itachi.
- The other Sharingan belonging to the original owner was used by Danzo in an attempt to make himself leader of the Shinobi Alliance, in the belief that only Danzo could use that position to bring about a lasting peace.
- Again the original owner of the above Sharingan tried to do this, presumably to Fugaku and the other leading Uchiha in order to stop the looming coup de' etat plotted by the Uchiha clan. Unfortunately for him, Danzo snatched his eye before he could even begin to put the plan into effect.
- In Neon Genesis Evangelion, it is possible to brainwash EVA pilots into fighting, but this is never actually used (presumably the results would not be pretty).
- In President Dad, to help Ami combat her stage fright when joining her dad (newly elected as president of South Korea) in addressing the people, Fahrenheit hypnotizes her into seeing the people outside as pumpkins. This is Played for Laughs.
- In Yu-Gi-Oh!, Marik's spell to brainwash Anzu was clearly not for a good purpose. However, after his Superpowered Evil Side dominated him, it quickly became this, as Anzu was now the only way he could communicate with anyone. For as long as he was able to, he controlled her in an attempt to seek help from others, first to tell his sister to keep Rashid hidden, and eventually to plead with the Pharoh not to hesitate to strike his dark side down (which was an issue due to the Sadistic Choice that the villain had forced the Pharaoh into).
- One Flash Gordon story centered on a tank-sized ray that could turn entire crowds into happy, good-hearted pacifists. Ming the Merciless takes control of it and use it to subjugate the opposition, until the protagonists manage to turn it on him. Flash even remarks what a swell guy Ming is when he's not evil. Justified since the ray's effect is temporary, and the rebound causes a lot of trouble later on.
- Snarfquest: It's evil on evil, but Suthaze magically brainwashes an evil dragon into thinking he is a friendly duck named Willie. Snarf breaks the spell temporarily to distract Suthaze, but it is rendered permanent by massive head trauma.
- At the climax of Kubo and the Two Strings, the villainous Moon King is struck by Kubo's musical magic, causing him to lose his powers and have his mind wiped. It's not clear if Kubo intentionally intended this or not (since he openly declared earlier that he would kill the Moon King), but regardless "Grandfather" is left with a blank memory and the villagers tell him that he's a great and generous man.
- Pound Puppies and the Legend of Big Paw ends with McNasty and his Mooks being put through his Mirror Morality Machine and coming out as nice people. Nobody seems to care that the process can easily be reversed by telling an affected person that you love them (or possibly that you hate them in this case).
- Used in Demolition Man by the San Angeles correctional system. Criminals are reprogrammed to be unable to perform the crimes they committed, and have useful skills or hobbies implanted. It's hit-and-miss, though; John Spartan can't stop himself from knitting despite being at best indifferent about it, and while Simon Phoenix can't kill Cocteau, he still really, really wants to, and eventually gets around it by asking one of his mooks to do it.
- Doc Savage: The Man of Bronze. At the end Doc performs one of his personality-altering operations on Captain Seas, who ends up as a member of the Salvation Army.
- Drop Squad. A group of black Americans kidnaps and deprograms (brainwashes) blacks who act like white people. The intent is to restore their pride in their own race (DROP stands for Deprogramming and Restoration of Pride). The movie justifies this by having the black man who's kidnapped working for a company that acts in an outrageously racist manner that would never be accepted in Real Life. Other kidnap victims include a corrupt politician and a drug dealer.
- If you count "removing all human emotions, positive and negative" as brainwashing, the dystopian government within Equilibrium uses this. Their justification is that Humans Are Bastards and uncontrolled passions caused all wars, so all citizens must take an emotion-neutralizing drug called Librium.
- In Men in Black, the organization uses a device called a neuralyzer on people to cause Laser-Guided Amnesia and purge any memories of aliens (which is truly for the best, something that we are repeatedly reminded of). They even use it on their own members who retire.
- Comes up in Serenity: the Alliance experiments with a bacteriological weapon that makes people placid. It works too well on 99.9% of the population of the test colony, Miranda. It causes a... reaction for the remainder. Somehow, the Alliance then alters all computer records to show that Miranda is -- and always has been -- uninhabitable.
- The use of the eponymous ark in the Stargate SG-1 movie Stargate: The Ark of Truth to convince the Ori's followers of the error of their ways could be viewed this way. While it is justified in that A) the Ori are dead anyway, and B) the Ori's followers are on the verge of overrunning the Milky Way, it's still brainwashing. Even Daniel, who found the Ark and figured out how to activate it in the first place, isn't happy that they have to use it, since it does mess with free will in a disturbing way. Even the fact that (at least according to Vala when the Ori Adria suggests she might use it herself) the Ark can only make people believe things that are actually true does not make it any less disturbing to them, and actually making use of the Ark is a desperate last resort.
- Pretty much any Jedi who uses the "Jedi Mind Trick" (used frequently in the Star Wars continuity) to get someone to cooperate is doing this.
- Danganronpa 2: Goodbye Despair reveals that the entire game takes place in a virtual world that stripped the 16 characters (except for Chiaki Nanami) of their memories from the time they were members of Ultimate Despair and would have replaced them with good memories and ethics. Unfortunately, thanks to the machinations of Izuru Kamukura, a virus was uploaded that allowed a virtual version of Monokuma to hijack the program.
- Fire Emblem Heroes: A Day in the Life: In "Adapting to a New Realm", the Summoner summons Hel, and Eir is worried that her mother is still hostile to the heroes that she was trying to kill before. However, the Magically-Binding Contract from the summoning apparently did this to Hel, and Eir gets unnerved by how submissive she now is.
- Mob Psycho 100: Dimple takes advantage of the Psycho Helmet urban legend to build a Cult of Personality and brainwash the people of Seasoning City into becoming disturbingly peaceful and willing to follow his every order. Mob eventually convinces Dimple he's just getting carried away in his desire to be important and loved, and Dimple is forced to stop anyway because the supernatural giant broccoli he was inhabiting becomes a mighty hostile entity of its own.
- MSF High:
- The Legion used to do this. A lot. Or, at least they saw it like that. Most people saw them as the "Heels", at times, and Legion transformations can have this effect, if done unwillingly. One of the reasons people don't like them very much. Generally, they don't do it now, though.
- Threatened in the forums, to this one guy, Dracon, by a Legion NPC. He HATES said NPC now, with a passion.
- Perfection Engine:
- The Eidolon King Animamundi completely transforms his kingdom and his people to strive for perfect morality and society as a form of penance for their Maker. The Eidolons and their King strive for their Maker to return to them, believing she was repulsed by their flaws and imperfections. Society is now peaceful, kind, beautiful, and perfect, one would think...
- Spinnerette: Sara Nicole Megan drugs her whole town in order to make everything nice there (at least by her standards-no crime, divorce, or gays-including herself.
- In the Dingo Doodles "Fool's Gold" campaign the party was trying to save the city of Rascam from its Lawful Evil, drug-dealing ruler the Bearon. When a fight broke out, Sips used a cursed item which randomly changed the Bearon's alignment to Lawful Good. It's not clear whether it was full brainwashing or simply giving him a conscience, but the Bearon has since become a good ruler and an ally of the party.
- In Effulgence, Aelise believed her world was in danger of being "nuked to a population of one." So she enlisted the help of Chelsa to brainwash everyone into loving each other, figuring that was better then everyone dying.
- hololive: Calliope Mori attempts to hypnotize Atlus into allowing her to play Persona 3 on stream by repeating her request over and over again for a solid two hours while "Burn My Dread" plays backwards for good measure. It's hard to say if it worked or not...
- Maven tries to hypnotize The Nostalgia Chick into never thinking about Todd in the Shadows again, but it doesn't even come close to working.
- In A Practical Guide to Evil if an Angel of Contrition is summoned into Creation, every mortal within forty-nine miles is made contrite - forced to witness every Evil in their life, accept they cannot be forgiven, and made to repent. Those people will then attempt to purge Evil from the world, usually by forming into a crusading army. The Lone Swordsman attempted this during the Battle of Liesse.
- SCP Foundation: SCP-2000 is a Reset Button that can recreate humanity in the event of an Apocalypse How. Behavioral and cultural modifications are noted to be possible with this SCP, and there's a suggestion it could be used to tone down the sociopathic and violent tendencies in humanity. They've toned it down as far as they could: to do any more would actually hinder humanity's progress. Think about that.
- In a Whateley Universe story, "Razzle Dazzle", Mephisto comments on Doc Wilde's claimed "surgical process that 'excised' a part of the brain that could work evil" and points out that it was basically a Lobotomy.
Townsend's eyes glittered, and his grin turned hard. "Simple. You CAN'T. It was brainwashing, plain and simple, accompanied by burning out certain bits of the brain with electric probes inserted directly into the cerebrum. Yeah, they were okay afterwards... mostly... but they got worse, mostly after people stopped paying attention. Now, while I didn't know all of the guys that he did that to, I DID know a fair number of them. And they were drooling wrecks, who could barely eat off a plate! .... Y'know, before, they'd been pretty sharp guys. Not NICE guys, but..." Townsend tapped his temple, "...sharp enough to be a challenge to Doc Wilde. Then? One of 'em had to work hard for an hour to tie his shoes!"
- Within the Wires' False Utopia ensures the nonviolence of its citizens in the aftermath of devastating war through a combination of cybernetically-enhanced repression of memories at age ten, and batteries of psychological programming. Season 1's protagonist is a patient, who, after illustrating deviant behavior, is supposedly undergoing a rehabilitative version of the latter during their stay at as an inpatient at a research hospital called the Institute.
- "Moral enhancement", or also called moral bioenhancement, that is, modifying the behavior and temperament of people through neuroscience to make bad people good and normal people morally better, is a growing topic of moral, ethical and philosophical discussion in light of science's ever-growing capabilities to alter the mind and soul. Most envisionings of moral enhancement have it as a voluntary procedure or do not specify, but it invokes this trope when mandatory application is discussed.
- The issues around moral enhancement can greatly vary depending on the type and way the moral enhancement is carried out. A method that represses the ability to do bad, for example, will have some different ethical and philosophical issues compared to a method that produces genuine goodwill (how authentic is an artificially induced goodwill compared to a "natural" one if they are otherwise subjectively identical is another point of debate). There are many differing approaches suggested: increasing self-control, enhancing prosocial emotions such as empathy and sympathy, applying a Restraining Bolt, or simple cognitive enhancement are among them. Whether it is a voluntary or obligatory procedure definitely also affects the issues to be discussed.
- The scale of a moral enhancement procedure also affects the issues that surround it. Moral enhancement has been discussed in scales and pervasiveness of application ranging from limited scope therapies for treating criminals with with disorders characterized by moral deficits (The Sociopath for example), to a global application to solve issues caused by Humans Being Bastards that is promoted by Transhumanists.
- One area of moral enhancement that particularly fits this trope is crime and justice, in particular because this is the area of moral enhancement where involuntary treatment is commonly debated, and because the benefits here are clear-cut. Issues specific to this area include the ethics of involuntary and voluntary treatment on convicts and whether consent to the procedure in exchange for reduced sentences is coercive.
- Surprisingly, voluntary moral enhancement is also an issue of debate, as in whether moral enhancement procedures should be available at all for people to choose to morally enhance themselves. While involuntary treatment has the ethical qualms that Brainwashing has, voluntary treatment is also opposed on the grounds of Appeal to Nature, effectiveness, differing moral standards, and the greater social impacts of it.
- Complicating matters is that there is no one moral standard on which to improve. This moral pluralism means that an action that is morally sound in one moral system can be immoral in another, as demonstrated by the thought experiment the Trolley Problem, in which one has to decide between killing one to save 5 or letting 5 die through inaction. Utilitarian philosophy holds the most moral action is the one that saves the most people, but Deontological philosophy contradicts it by regarding the act of killing itself to be immoral, despite being the route that saves more people. There is also the issue that moral enhancement can have side effects. Enhancing empathy, for example, could lead to increased partiality for those we care about at the expense of strangers, while enhancing generosity could allow less scrupulous people to more easily exploit them.
- Chemical castration, which takes the form injecting hormones to lower androgen levels in the body, is sometimes performed as a voluntary or mandated procedure on convicted child molesters and rapists to lower their sexual desire and reduce the likelihood that they will commit another sexual offense.
- When homosexuality was still a crime in most Western nations, many gay men were chemically castrated, including Alan Turing. It's commonly believed to have been a factor in his suicide.
- And others were and are subjected to "conversion therapy" in an attempt to make them heterosexual. The practice is condemned by every reputable mental health association and some jurisdictions have banned it from being performed on minors.
- When homosexuality was still a crime in most Western nations, many gay men were chemically castrated, including Alan Turing. It's commonly believed to have been a factor in his suicide.
- Education is generally not regarded as brainwashing (except in places like North Korea and China), but like parents, the school environment, its conduct and policies, and what is taught there has a really significant impact on the moral development of children, and many teachers consider it their responsibility to make sure for the children's and society's sake that the children they look after grow up into decent people.