Many villains walk a thin line between good and evil; indeed, many villains have redeemed into remorse, sympathy or even empathy, and once arrogant villains ascend further into the path of good, often fighting against people they once protected or fought alongside, they begin to turn away from their old ways.

Originally antagonists or forces of evil, these characters turn good due to events in their lives, such as an idealism or encouragement from another hero, their positive change of heart, a good relationship with others (perhaps a successful love story), recognizing their own inner goodness and capacity for good, betrayal or any other unresolved traumatic experience in which they question whether or not the dark side is worth fighting for. However, some villains may turn for more satisfying reasons.

A Redeemed Villain, otherwise known as villain turned to the good side or Former Villain, is usually the end result of an antagonist exposed to an Outright or Purely Good hero, a Messiah, a Passively Empathetic character, a Hope Bringer, and occasionally a Charismatic Hero. In some situations, some villains turned to the good side can even become Pure Good to add drama as they are willing to be good without any despair, corruption, or negative qualities after all. Good examples include Max Damage, Asgore and King Neptune.

There are various scenarios why these individuals turned to the good side, though the said individual often redeems into multiple scenarios altogether:

• From Possessed/Brainwashed to Freedom: snapping out of a possessed or brainwashed state and deciding to aid the hero who freed them. The villain is a hypnotized, brainwashed or possessed pawn who does not know they are being controlled until they are free. Grateful to whatever hero freed them, they ally with them. Baroness (in the 2009 film, G.I. Joe: Rise of Cobra), Cyrax, Hawkeye (in the 2012 film, The Avengers) and Koragg (in Power Rangers: Mystic Force) are very good examples.
• Righteousness: being exposed to the Messiah or incorruptible type of hero that helps them to see their errors. Usually done with delusional, honorable or insecure characters (the villain can also have all those traits) who believe they are doing right, or just want to be loved. The hero reveals to them that their actions are actually causing harm, or tries to comfort them. The individual chooses their desire for righteousness over what they have done, and/or decides the hero had helped them see what they were doing was wrong, and becomes a full-time hero. Gaara and Prince Zuko are two prime examples of this.
  • Remorseful Heroes: In this sub scenario, usually in more light-hearted media, and if the villains areaffable, in love, and/or just plain jerks, the HEROES are the ones who apologize to the villain for provoking them into their evil ways, the villains forgive them and stop being evil. Example: Peter Rabbit and Benjamin Bunny rush back to Harrods in London to apologize to Thomas McGregor for tormenting him ever since his arrival at the McGregor manor and framing him for blowing up their burrow.
• From Abandoning Evil to Good Honor: choosing honor before evil. A honorable villain decides that their own honor, or the honor of something or someone else is more important than what they are doing and decide to abandon their evil actions. Often done with supporting antagonists who value the lives of innocent people over working with their evil/cruel masters such as Jeanne from the first Bayonetta game and Phoebus from Disney's The Hunchback of Notre Dame.
• Hostility turned Friendship: becoming friends with someone and decide to help them over being evil, such as Axel. He had planned on betraying Organization XIII with Saïx, but over time he builds a friendship with 2 other members, Roxas and Xion and decided he was happier being with them rather than plotting with Saïx. Pupa (in the 2014 film, Let's Be Cops), he explains to Justin Miller and Ryan O'Malley (the fake police officers) that he hates Mossi Kasic and his thugs; he explains to them that he doesn't know about what's inside those crates at Mossi's party, he decides to forget about being bad and wants to be a good friend of Justin and Ryan and El Tigre, who learns that friendship is more important than hurting people.
• Deciding the Good Family for Care: choosing their family over evil. Done with villains who have families and to care for them. They realize that their actions are actually hurting their spouses, children, siblings or any other members in their family. Two memorable examples are Anakin Skywalker (aka Darth Vader) and Nikki Pimvaire (aka Necrolai).
• Snapping out the memory-wiped/brainwashed: being memory-wiped or brainwashed into becoming a hero and deciding that they like their new personality and life better then their old ones when they inevitably learn the truth. This is the rarest and most controversial form of a villain redeeming themselves since they did not turn good by their own free will and essentially had to be programmed into being good. Reserved only for villains who would normally be a Pure Evil under their circumstances, the audience or reader meets them as a hero first, not knowing they are brainwashed or have fake memories. The "hero" does not know this either and is just as horrified as the viewer when they learn the truth about the horrible things they have done or regain their real memories. But they have spent so much time as a hero and living with an artificial good personality that they choose their new life over their former one and become true heroes. One famous example is Darth Revan.
• Betrayal of the Dark Side: betrayed by their fellow villainous allies/bosses, which made them choose to transfer to the good side. After they were tasked to antagonize the hero and they were successful, their allies/bosses throw them under the bus or try to kill them straight away (in either way). Having see their errors (and in the worst case, hunted down by the Big Bad or their former ally), they choose to work for the good side by joining forces with heroes. Bad Cop/Good Cop, Discord, May Day, Other Father and Owen Shaw are good examples.
• Retirement of Being Evil: retiring from being a villain and realizing that living as a good guy is better than their previous lives as evil-doers. Deckard Shaw, Gru, Karone (aka Astronema), Megamind and Scarlet Witch (in the 2015 film, Avengers: Age of Ultron) are good examples.
• Decide to Move On Forward: some of them move on forwards, without going back; one memorable example is The Timekeeper from Spy Kids 4: All Time In The World.
• Remorseful Correction: learning the lesson of being evil from another villain (Usually a Necessary Evil, a Monger or in the worst of the cases a villain who is pure evil), in other words having a case of "taste of your own medicine", which leads them to understand that they are doing the very bad thing the other villain is doing and feel very horrified, disgusted and terribly bad for the actions of the latter villain and try to redeem herself/himself and fight against her/him (Similar but somewhat different to a case Evil Vs. Evil), in the end of the battle (Usually in the end of the very battle/episode/movie or in sequels) he/she tries to join the heroes and search for pardon from everyone they had become enemies to. Selina and Shadow the Hedgehog are good examples.
• Simply Stopping Being Evil: there are rare cases where, though they have no real reason, a villain can just decide to stop being evil. Perhaps they tire of it or have successfully completed their goals and have no reason to antagonize anyone anymore. Some of these villains may not be remorseful like other redeemed villains, and instead are proud of what they have done but simply have "retired" from villainy. An example is James Earl Cash.

If the hero is currently in an On & Off status, they are NOT redeemed unless they stayed good right up to the very end of the story.

NOTE:

Pure Evil villains have no chance of any redemption since they're completely beyond it, no matter the circumstances. Likewise, it is impossible for a redeemed character to revert back to their evil ways unless they are possessed/brainwashed by another villain (or villains), but even then, the redeemed villain STAYS redeemed.

Furthermore, Villains who joins the heroes' sides out of PRAGMATIC and SELF-SERVING needs, but still retains their villainous nature, can NEVER count as Redeemed. It's highly likely that these types of villains WILL slip back into their evil ways once their needs are fulfilled. (examples include Sosuke Aizen, Frieza and Ceaser Clown)​​​​

If some villains were considered as Pure Evil but eventually redeemed themselves, it means that they were never Purely Evil in the first place.

False villains, if they never were evil, do not count (e.g. Enfys Nest from Solo: A Star Wars Story)