The idea of a villain becoming a hero is not new to comic books. In 1964, Captain America famously invited Hawkeye, Scarlet Witch, and Quicksilver into the Avengers, three former villains looking for a shot at redemption. These were misguided, misunderstood characters who were victims of bad decision-making. Comic books have since seen countless villains change their ways under similar circumstances.

Reformed villains like these are a dime a dozen, but how often do we have a real villain join up with the good guys? Not all reformed villains can make the excuse that "they really weren't all that bad." Some have gone so far that it's hard to believe they could ever have a change of heart. These characters haven't just walked the line between good and evil, they've strayed so far from it that any attempt at redemption seems like a well-contrived plot. So with that said, let's have a look at 15 Reformed Comic Book Villains Who Used To Be Totally Evil.

15. Juggernaut

Juggernaut as one of the X-Men, Cyclops, Wolverine, Beast

As one of the most recognizable villains in comics, Cain Marko has had a long history of terrorizing the X-Men with his massive frame and incredible strength. Powered with the Gem of Cytorrak, Juggernaut launched his first attack on the X-Men in an attempt to murder his step-brother, Professor Charles Xavier, a person he blamed for many of the hardships he endured as a child. After being defeated, Juggernaut allowed his hate and anger to drive him to commit even more acts of violence against Xavier and his students.

After years of being characterized as a bully who thrives off taking pleasure from others' pain, Juggernaut's image began to change in the early 2000s as he and his friend Black Tom joined the X-Men as part of a plan to destroy the team from the inside. When Black Tom betrayed him, Juggernaut considered taking a different path and stayed with the X-Men. He's also served with the Thunderbolts under Luke Cage.

14. Lobo

Batman Lobo Justice League Vs Suicide Squad Comic Book

Lobo is an intergalactic bounty hunter who gets more thrills from senseless violence than the money he earns from his jobs. This is a character whose name translates to "one who devours your entrails and thoroughly enjoys it." Banned from both Heaven and Hell, Lobo loves to fight and takes every chance he can get to deal out some pain, whether it be Superman or some other unfortunate soul unlucky enough to encounter him.

Some readers may defend Lobo, claiming that the bounty hunter has a strong sense of honor. He has never broken a promise, and after the recent reboot, Lobo has even become a member of the Justice League. However, being a member of the JLA doesn't erase his record. After all, Lobo is guilty of the greatest sin any comic book character could possibly commit: he murdered Santa Claus. If that's not the epitome of evil, then what is?

13. Clayface (Basil Karlo)

"Clayface" is the name given to a number of Batman villains with clay-like bodies. All Clayfaces have the ability to alter their body shapes, with each having a distinct power that differentiates them from the others.

The first version of Clayface was introduced in 1940. Basil Karlo was a disgruntled actor who went on a killing spree, murdering several actors set to star in a remake of one of his films. Karlo, a character obviously inspired by Hollywood horror legends Boris Karloff and Lon Chaney Sr., was the only Clayface not to possess any powers at all until he injected himself with samples of other Clayfaces. After proclaiming himself "The Ultimate Clayface," Karlo renewed his reputation as a notorious Batman villain.

The latest DC comic book reboot dismissed the character's history as a murderer and redefined him as a hero who joins Batman on a quest to defend Gotham.

12. Venom (Eddie Brock)

Spider-Man shaking hands with Venom

Of all the villains who have bonded with the "Venom" symbiote, none are more memorable than the irresponsible journalist named Eddie Brock. Blaming Spider-Man for all his failures, Brock became consumed with hatred and committed himself to the goal of killing Spider-Man. His overwhelming hunger for Spider-Man's death has even led him to murder. He hounded Spider-Man so much that on one occasion, the wall-crawler decided to let Brock have the victory he so desperately craved and allowed him to think that he had killed him.

Brock showed little regard for human life until an incident where Brock chose to save the life of an innocent baby. Since that day, Brock has displayed similar acts of compassion and has even been able to put aside his hatred for Spider-Man long enough team up against powerful threats like Carnage.

After becoming "Anti-Venom," Brock used his abilities to cure people who were infected with Spider-Man's powers during Spider-Island. The cost was his symbiote, leaving Brock powerless but with the reputation of a hero.

11. Ares (Marvel version)

Ares pointing to someone off-page in Marvel Comics

In Marvel Comics, Loki is to Thor as Ares is to Hercules. The God of War has had his sights set on the throne of Olympus since the 1960s. Ares has plotted with villains such as the Enchantress, Hera, and Pluto to conquer Olympus and kill his half-brother, Hercules. Ruthless and cunning, Ares will do anything to overthrow Zeus and take control of Olympus.

Over the last fifteen years, Ares has become more involved in the affairs of superheroes than he has in the past. He joined Iron Man's new team of Avengers after the end of the Civil War and became a force for good. He later joined Norman Osborn's Dark Avengers, believing that despite Osborn's questionable tactics, what they were doing was right for the planet Earth.

Ares' trust in Osborn led to his downfall when he discovered that Osborn had been manipulating them. Acting on Osborn's orders, Sentry brutally murdered Ares by ripping him in half.

Ares has since been resurrected, allowing him to resume his career as a hero.

10. Poison Ivy

Batman fighting Poison Ivy's monster Harvest

Beautiful and charming, botanical biochemist Pamela Isley is an eco-terrorist whose criminal schemes are motivated by a love for plant-life. With the ability to control plants, Poison Ivy has become one of the most well-known villains in Gotham City and a staple of Batman comics.

Poison Ivy has gone to great lengths to protect the natural environment. Though this may seem like a noble goal, her actions are the furthest thing from noble. She has no qualms about killing innocent people and clearly values the lives of plants over the lives of human beings. She has even fed people to a plant to keep it alive, an act which she described as a "guilty pleasure."

In recent years, Poison Ivy has been portrayed more heroically than usual but has occasionally returned to her villainous roots. As a fan-favorite, Poison Ivy headlined her own miniseries in 2016 and is currently a recurring character in Harley Quinn's self-titled series.

Though it hasn't been confirmed, it's been suggested that Poison Ivy may be appearing in the Suicide Squad spin-off film, Gotham City Sirens, alongside Harley Quinn and Catwoman.

9. Emma Frost

Longtime girlfriend of Cyclops and X-Men leader, Emma Frost has a record of deception, murder, and manipulation as the White Queen of the Hellfire Club. In her first appearance, Frost schemed with her allies in the Hellfire Club to murder the current leader and seize his power. Using her powers of telepathy as a tool to achieve her own ends, Frost participated in many schemes designed to serve the interests of the Hellfire Club.

At first, it seemed that the only thing that was able to soften the cold heart of Emma Frost was her students, children that she tutored at a mutant academy. Her affection for her students was what eventually led her to her association with the X-Men. As the years passed, her connections to the team grew until the point when she was eventually given a job as a teacher. She developed a relationship with Cyclops, causing her ties to the X-Men to grow even stronger. After obtaining a leadership position with the team, Frost embraced her new responsibilities.

Emma Frost has certainly come a long way from the White Queen, but the recent death of Cyclops seems to have hit her hard. In the latest Marvel Comics event, Frost appears to have gone back to her olds ways by scheming up a war with the Inhumans.

8. Power Man/Atlas

Criminal and mercenary Erik Josten was transformed into "Power Man" by the Enchantress using the same ionic energy technology that turned Simon Williams into "Wonder Man." Though not as powerful as Wonder Man, Josten quickly became a villain of the Avengers and an ally of Hawkeye's former mentor, the Swordsman. The duo tried several times to kill the Avengers and when that failed, they joined a group of villains called the Lethal Legion.

The duo of Power Man and the Swordsman finally broke apart when the Swordsman reformed and joined the Avengers. More ruthless and cruel than the Swordsman, Josten continued his criminal activities and had to look for new partners. After gaining the ability to increase his size, Josten adopted the name "Goliath." One of his most notable acts of brutality is his participation in the beatdown of Hercules during an attack on Avengers Mansion.

Along with a few others, Josten was recruited by Baron Zemo to fight the Avengers, but their plans fell through when most of Earth's superheroes seemingly died in a battle against Onslaught. So Zemo and his crew instead formed the Thunderbolts, villains masquerading as heroes. "Atlas" became Josten's new superhero identity. When Zemo was ready for the ruse to end, Josten was among the villains who decided that they liked being heroes.

7. Sabretooth

Introduced in the 1970s as a savage, ruthless enforcer and recurring foe of Iron Fist, Sabretooth soon evolved into the hated archenemy of Wolverine. Enhanced by the Weapon X program, Sabretooth became one of the most dangerously brutal characters in the Marvel Universe. Though he and Wolverine share much in common, unlike the X-Man he kills because he enjoys it. He has also hunted down and nearly killed Wolverine every year on his birthday just to prove that he can.

During the Marvel Comics event series, AXIS, Scarlet Witch and Doctor Doom cast a spell that "inverted" heroes into villains and villains into heroes. Sabretooth was transformed into a more heroic version of himself. When the inversion spell was reversed, Sabretooth was protected by an energy shield, allowing the inversion to become permanent. After pledging to redeem himself for his past crimes, Sabretooth joined the Avengers Unity Squad under the leadership of Rogue.

6. Black Adam

Black Adam sits on his throne in DC Comics.

The tragic character of Black Adam has been a terror to the Marvel Family since 1945. Possessing the powers of six Egyptian gods, Black Adam is truly a force to be reckoned with. He was selected by the wizard Shazam to be a hero, but in time Black Adam gave in to his own needs for conquest and became a vicious ruler to his people. Seeing what Black Adam had become, Shazam trapped his soul inside an amulet. Centuries later, Black Adam and Shazam were both reborn into new bodies, paving the way for the two to become bitter enemies.

Black Adam has changed directions several times over the course of his rich history in the DC Universe. He has served as a member of the Justice Society of America and the Suicide Squad, as well as a member of various evil organizations, including the Injustice League and the Secret Society of Super Villains. While on these teams he's been a hero, a villain, an anti-hero, and a traitor.

5. Harley Quinn

After being introduced on Batman: The Animated Series as a female sidekick to the Joker, Harley Quinn became a fan-favorite and was eventually given a place in the comic books.

Before her association with the Joker, Dr. Harleen Quinzel was a young and innocent psychiatrist whose impressionable mind was taken advantage of by the Joker, who at the time was a patient in the Arkham Asylum. She became his partner, aiding him in many of his evil schemes, often appearing to be as deranged as he was. Harley Quinn was always OK with murder, and her relationship with the Joker was troubled only by his constant abuse toward her.

When not working with the Joker, Harley Quinn has shown that she can be more than just an accomplice to a psychotic killer. Since being reinvented as an anti-hero, Harley Quinn has proven to be a successful crime-fighter. We can only hope that she doesn't rediscover her affection for her former partner-in-crime...

4. Loki

When Norman Osborn recruited Loki into his organization of supervillains known as the Cabal, it was Loki who convinced him to launch an invasion into Asgard. Having failed numerous times to take the throne for himself, Loki had decided to throw his support behind Osborn. However, when Loki realized that the destruction of Asgard was not what he really wanted, he tried to stop Osborn, only to be destroyed by the Sentry.

This was not the end of the God of Mischief. Loki was reincarnated into the body of a young boy. Oblivious to his past life as an evil god, Loki was working as a street hustler in Paris until some of his memories were restored by Thor. In an attempt to become something better, Loki joined the Young Avengers as a superhero.

The emergence of an evil, future version of Loki—called King Loki—is a foretelling sign that Loki's dedication to his new cause may not be permanent. Despite this revelation, the young Loki is determined to avert this future from ever happening.

3. Lex Luthor

Superman isn't exactly thrilled about it, but the Justice League of America has recently inducted a new member: Lex Luthor. The pre-Flashpoint Superman was skeptical when he first heard news of Luthor being a hero, and rightly so. Luthor tried to convince him that his goal was to serve as the protector of Metropolis. Superman didn't have much time to argue as they were soon interrupted by an attack from Doomsday. Luthor helped Superman in the fight against Doomsday and succeeded in saving many innocent lives.

In other adventures, Luthor is also responsible for saving the lives of Nightwing and Superman, funding a new watchtower for the JLA, and recruiting Shazam and Captain Cold to the team. Considering all the contributions Luthor has made to the team  in recent months, it's hard to imagine what kind of grand plan he could have up his sleeve. Though it may seem that he's turned over a new leaf, let's not forget that we're talking about Superman's ultimate nemesis, a person who has dreamed of world domination for decades. Is it possible for someone like Luthor to ever be anything but a bad guy? The answer to that isn't clear. Only time will tell...

2. Magneto

Some may argue that Magneto, the Master of Magnetism, who now operates as one of the leaders of the X-Men, was never really "evil" per say, and was simply "misguided" or "misunderstood" due to the horrors he witnessed in a concentration camp during World War II. Magneto wouldn't be the first mutant to believe in the cause of achieving equality for mutantkind, but Magneto took this cause a step further. He didn't want mutants to live in peace with humanity; he wanted mutants to rule over the humans because they were superior. If there are any other doubts about Magneto's true nature, look no further than the name of his team: "The Brotherhood of Evil Mutants."

Magneto constantly tried to stir up conflicts between the humans and the mutants. He once used his powers to manipulate a bullet fired from the gun of a police officer and forced it to hit Scarlet Witch in order to gain the support of her brother, Quicksilver.

So after years of creating division between humans and mutants, Magneto seems to have finally found his place in the X-Men and has been a powerful voice on the team for quite some time. Will it last?

1. Doctor Doom

The ruler of Latveria, Victor von Doom, has been the enemy of the Fantastic Four since 1962 and the enemy of the Marvel Universe since the 1980s when he tried to steal the Beyonder's power on Battleworld. Doctor Doom's attempt to take over the universe failed, but he received a second chance in the recent Marvel event, Secret Wars, when he used the power of the Beyonders to create his own version of Battleworld, a place where he was "God Emperor Doom."

When Doom was eventually defeated, he realized that being God Emperor Doom did not give him the happiness he had expected, leading him to abandon any future plans for world domination. Doom decided instead to use his talents for good, and after Tony Stark fell into a coma, Doctor Doom took the Iron Man name and is now the star of his own comic, The Infamous Iron Man. In this series, the scars on Doom's face that have been an iconic trait of the character for 50 years are finally gone due to the reality manipulations of Mister Fantastic and Molecule Man. The change to Doom's physical appearance is a reflection of his metamorphosis into a hero.