As fun as it is to see all the iconic heroes who are brought into the MCU, it is just as exciting to see how some of the villains are adapted to the big screen. In some cases, like with Loki or Red Skull, these Marvel bad guys fit quite closely to their comic book counterparts.
However, the MCU has never been afraid to change the source material, and some of these villains bare little resemblance to the comics. Whether it is to fit the story or to fit the live-action world of the MCU, these villains have undergone the most drastic changes when being brought into the movies.
Arnim Zola
When Arnim Zola first appears in Captain America: The First Avenger, he mirrors the comic book character fairly closely as a scientist working for Red Skull and Hydra. However, it is the character's evolution that sees things differ quite a bit.
In Captain America: The Winter Soldier, Steve Rogers discovers Zola has ed his consciousness into a computer in order to stay alive. In the comics, it is actually a giant robot that Zola inhabits, making him a much more formidable foe than simply an out-of-date computer.
Killmonger
Erik Killmonger from one of the best MCU villains. As the son of N'Jobu, the brother of Wakanda's King T'Chaka, Killmongger was left behind in America after his father was killed and later seeks to rule Wakanda and help all of the African descendants around the world to free themselves from their oppression.
Killmonger shares some of these similarities in the comics as he does blame T'Chaka for the death of his parents and grew up outside of Wakanda. But he lacks that connection to T'Challa and is far less sympathetic or complex in his motivations as he simply wants revenge.
Taskmaster
In the comics, Anthony Masters is a mercenary who is hired by various criminals to take on the Marvel heroes. He also possesses a photographic memory when it comes to his reflexes which allows him to mimic any fighting style that he sees.
In Black Widow, Taskmaster keeps the unique fighting skills, but little else is the same. The character is reimagined as the brainwashed daughter of Dreykov, the leader of the Red Room. She is used as a mindless weapon which makes her a much more sympathetic villain than simply a formidable mercenary.
Baron Zemo
Baron Zemo is one of Captain America's greatest foes in the comics. Known for his purple mask, Zemo is a German noble who seeks revenge on Captain America after his Nazi father is killed fighting the hero in World War II.
Zemo makes his MCU debut in The Falcon and the Winter Soldier re-establishes some comic book details, retroactively making him a baron and giving him his mask.
The Mandarin
The controversial comic book character of The Mandarin was primarily seen as Iron Man's greatest villain. He was born in China following the Communist revolution and would go on to discover ten powerful rings that he used in his attempts to take over the world.
After the character fake-out in Shang-Chi. He is reimagined not only as an ancient warrior given immortality thanks to the rings but also as the father of Shang-Chi. He is also less evil as he uses his powers in a misguided attempt to bring back his late wife.
Vulture
Vulture is one of Spider-Man's oldest nemeses who finally made his big-screen debut in Spider-Man: Homecoming. In the comics, Adrian Toomes is an inventor who builds a flight harness and uses it to commit crimes when his business fails.
In the MCU, Toomes is made into a blue-collar worker who loses his job thanks to Tony Stark. He then uses the alien technology recovered from the Battle of New York in order to become an arms dealer of powerful weaponry.
Ghost
Ghost is a fairly obscure villain from the comics who was mostly used as a villain of Iron Man. There is a lot of mystery around the character as well, including the fact that his name was unknown. But Ghost was usually only seen in the phasing suit that allowed him to target tech companies and sabotage them as a tech terrorist.
In Ant-Man and the Wasp, Ghost is a female character who was affected by her father's experiment as a child and gave her the phasing abilities which are very painful for her. As a result, she seeks to find a cure using the power of the Quantum Realm.
Thanos
As one of the biggest villains in Marvel comics, Thanos also became the most significant villain in the MCU. Similar to the comics, he is a powerful being who uses the Infinity Stones to snap half of the universe out of existence.
However, the important distinction is that the motivation for this act is very different in the movies than it is in the comics. In Avengers: Infinity War, Thanos is presented as a hero in his mind, destroying half of all life so the remaining half can flourish, making him a complex villain. In the comics, Thanos does it simply to impress Death who he is in love with.
Mysterio
Mysterio is yet another Spider-Man villain who has ties to Tony Stark in the MCU. However, in the comics, Quentin Beck is a special effects man who uses his skills to pull off illusions and even commit crimes while making it seem like Spider-Man is to blame.
Spider-Man: Far From Home reveals Beck is the man behind Stark Industries' BARF technology seen in Captain America: Civil War which he then uses to create a global threat and position himself as the hero who will save the day.
Ikaris
Ikaris represents an MCU villain who was changed so drastically that he was actually a hero in the comics. Ikaris is the brave and noble leader of the Eternals with powers that rival Superman. He is very much like Captain America in the sense of a leader who is only concerned with doing what is right.
In Eternals, Ikaris is still a prominent and powerful member of the team, but his morals are much less heroic. Not only does he kill their leader Ajax, but he also turns on the rest of the team so he can fulfill his duties of allowing the Celestials to destroy Earth.
