The villains in the MCU are often inspired by the same character in Marvel Comics. However, not all of the villains in the MCU are fully adapted from their comic book versions, some are created with different characteristics.
Specifically in the Marvel movies, there are some characters who are supposed to be good but turn bad and become villains. Here are some examples of characters who are good in Marvel comics but turn bad in movies:
1. Alexander Pierce
Alexander Pierce in the comics is a loyal agent of SHIELD. But in the movie version of the MCU, Alexander Pierce is one of the main villains in Captain America: The Winter Soldier. It is revealed that Pierce is a member of HYDRA in the MCU.
2. Sharon Carter
Sharon Carter in the Marvel comics once killed Captain America, but that was due to the influence of Dr. Faustus. Apart from such moments, she is presented as a good character. Meanwhile, for the MCU version, specifically in the movie The Falcon and The Winter Soldier, Sharon Carter has revealed that she is a mysterious Power Broker.
Even at the end of the movie, after receiving a complete amnesty from the US government, Sharon shows no sign of repentance. She even intends to sell classified information about the US government, weapons and other things. With a situation like this, Sharon has the potential to become a major villain in the MCU.
3. Jasper Sitwell
In the comics, Jasper Sitwell is Nick Fury’s assistant and a brainwashed SHIELD agent who first worked for HYDRA, but after all he reverted to being loyal to SHIELD. Meanwhile, in the MCU version, Sitwell turns out to be one of SHIELD’s agents secretly working for HYDRA.
Ikaris in the manga version is a heroic character. What about the MCU version of Ikaris? At first, he seemed to be on the side of the Eternals. However, it was later revealed that he was very loyal to Arishem, which led him to fight against his own allies. It turned out that Ikaris was the one who caused Ajak’s death. Originally, he was one of the main characters of the film, but in the end he became the unexpected villain of the story.
5. Ronan the Accuser
In the comics, Ronan is a controversial character, sometimes a villain, sometimes a hero, like many other Marvel characters. At one point, he was an anti-hero and helped many Inhumans and Avengers in many adventures.
But Ronan in the MCU version, despite being a main villain, ended up fading away in the first Guardians of the Galaxy movie.