Superhero movies tend to have the reputation of stories that primarily focus on action and special effects, not so much the storyline and the character building. As the MCU proved multiple times, that’s not always the case. Even though action scenes play a big part in the movies, so does the character growth.
MCU heroes and villains alike have changed over time, as long as they got enough space to do so. As a result, even those who were once egoistic or downright evil became much more sympathetic in the end. While many MCU characters changed, in some cases the change was much more noticeable and significant for the plot as well.
5 Loki
Loki is one of the few villains, if not the only one who got a whole redemption arc leading from a villain to a hero. When he first appeared in Thor (2011), Loki was uncertain of his father’s love for him, jealous of Thor, and wanted to gain as much power as possible.
Loki had continued coming up with evil plans in the future as well, but he gradually became more aware of what was right and wrong, which could have been partially caused by the death of his mother Frigga, and the impact it had on Loki. After the loss of their father Odin, Thor and Loki seemed to have bounded in Thor: Ragnarok (2017) and fought side by side to save Asgard. Loki then fought Thanos and lost, dying as a hero. Since he’s now back in the MCU and no longer as evil as he once was, Loki has another chance to demonstrate how much he has changed as a person.
4 Nebula
Unlike Loki who was controlled by his jealousy and feelings of inadequacy, Nebula had a much harder starting position. Growing with up a father who punished her and stripped away parts of her body anytime she wasn’t strong enough left Nebula bitter and angry toward the entire world, and especially her more successful sister Gamora. So much so that when Nebula finally got the chance, her biggest wish was to kill Gamora in the first Guardians of the Galaxy movie.
In the sequel, though, Nebula showed what hid deep inside her and instead of fighting the Guardians, she joined their side. She then went on to battle Thanos and was one of the reasons why Tony Stark survived after being stranded in space. When Nebula opened herself up to others, it changed her into a more sensitive person, yet she still remained a formidable warrior, making the best of two worlds.
3 Bucky Barnes
Even though he was originally a supporting character, Bucky Barnes got one of the most complex character arcs in the MCU. When the viewers first met him, he was Steve Rogers’ loyal friend, charming, determined, a hit with the ladies, brave and strong. After being captured and presumed dead, Bucky was amnesiac, brainwashed into killing people, and became known as the Winter Soldier.
Thanks to Steve’s help, Bucky broke his programming and had to deal with the consequences of what he did in the past. Bucky struggled with finding his place in the world, especially after Steve died, but by the end of the first season of The Falcon and the Winter Soldier, it looked like Bucky had finally come to peace with himself and with what he was forced to do.
2 Bruce Banner
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Just like Bucky Barnes, Bruce Banner also had to defeat his inner monster… or what he perceived as a monster. When Bruce first appeared in the MCU, not only did he have a different face (Edward Norton’s), but he was also scared of transforming and even contemplated taking his own life. Bruce joined the Avengers and helped them defeat Loki and the Chitauri army while being constantly angry.
As time passed, Bruce managed to reconcile his two halves and found a way how to build a bridge between the strength of Hulk and the intelligence of Bruce Banner. The result was seen in Avengers: Endgame (2019) and most lately in She-Hulk where Bruce was shown living a peaceful life, albeit saddened by the loss of his friends, Tony Stark included.
1 Tony Stark
As the man who started the MCU, it’s only appropriate that Tony Stark is also one of the MCU characters that have changed the most. In Iron Man (2008), Tony Stark was arrogant, self-assured, and unwilling to open his eyes and see what his company and the people around him were doing to the world. Stark was never a team player, but he had to learn how to get along with others when he joined the Avengers.
It was the first time he proved he could be truly selfless when he flew the nuke into space, risking his own life. As Tony aged, he matured, started a family, and turned out to be a loving father, miles away from the irresponsible playboy he once was. In the end, his character arc closed when Tony sacrificed his life to defeat Thanos once and for all, which only demonstrated further that Tony Stark in Avengers: Endgame couldn’t be more different from the one at the beginning of Iron Man.