The Marvel Cinematic Universe plays host to many larger-than-life characters, and some have undergone some truly staggering development over time.

The characters of the Marvel Cinematic Universe have helped make the franchise one of cinema’s most successful properties, and the continuity has seen many of its characters undergo incredible development. Since the start of the MCU’s movie timeline, the franchise has introduced countless characters adapted from the pages of Marvel Comics. The narrative hasn’t confined itself to simply following the source material, taking many creative liberties to make its stories as entertaining and engaging as possible.

One of the biggest ways that this manifests in the movies of the MCU is through character development. Many heroes and villains have changed substantially from the time they were first introduced into the franchise, often informed by audience reactions to and popularity of specific characters or character traits. As a result, many MCU characters have undergone brilliant changes over their franchise story, growing and adapting with each new obstacle thrown at them. With that in mind, here are the 10 MCU characters with the best development of all time.

10. Spider-Man Has Developed From An Idealistic Kid To A True Hero

Introduced In: Captain America: Civil War (2016)

When it comes to substantial character development, the MCU has wasted no time in building up its own iteration of Spider-Man. Tom Holland’s Peter Parker was first introduced in Captain America: Civil War, when he’s brought in by Iron Man to fight alongside the Avengers in support of the Sokovia Accords. The older hero then acted as a mentor to Spider-Man until his heroic sacrifice in Avengers: Endgame.

By the end of Spider-Man: No Way Home, the MCU’s Peter Parker has lost everyone important to him. Sacrificing his identity and his relationships with his loved ones in order to save the Multiverse, Spider-Man is by far one of the most selflessly heroic figures in the MCU. Considering his arc has been a relatively short one, he’s undergone a huge and important amount of character development in that time.

9. Rocket’s Personal Story Has Been Incredibly Powerful

Introduced In: Guardians Of The Galaxy (2014)

Though he may not be one of the MCU’s most prominent figures, Rocket has proved particularly popular as part of the Guardians of the Galaxy. First introduced as the prickly, technologically gifted, and morally bankrupt member of the team, Rocket’s journey has been especially powerful. His arc throughout the Guardians of the Galaxy trilogy has seen him go from a comedic character to a tragic one without changing much in his actual personality.

Rocket’s backstory was vaguely established in his debut appearance, with more information revealed in Guardians of the Galaxy Vol. 2. The final movie in the trilogy delved deep into Rocket’s origins, exploring the horrific nature of his creation at the hands of the High Evolutionary. Rocket’s journey brought him around to reconcile with his past and accept himself, with Guardians of the Galaxy Vol. 3’s post-credits scene establishing him as the new leader of the team thanks to his massive personal growth.

8. Wanda Maximoff Is One Of The MCU’s Most Tortured Figures

Introduced In: Avengers: Age Of Ultron (2015)

First established in one of the MCU’s post-credits scenes, Wanda Maximoff made her full debut in Avengers: Age of Ultron, first acting as an antagonist before switching sides to become an Avenger. Subsequent movies saw Wanda act as a full-fledged hero, but suffering repeated losses of those close to her drove her to dark places where she began to access the true scope of her powers, setting up her villain turn in Doctor Strange in the Multiverse of Madness.

Wanda’s MCU arc saw a huge amount of development, taking her from a young, radicalized villain to a complex and tragic figure. Her story through the movies and TV shows of the MCU transformed her from a promising member of the Avengers to a woman who had lost everything important to her, contributing to her later fall from grace. Wanda’s story in the MCU was filled with tragic twists and turns, making her a particularly compelling character in the process.

7. Star-Lord’s Character Arc Has Seen Remarkable Growth

Introduced In: Guardians Of The Galaxy (2014)

Star-Lord’s role as a hero in the MCU is understated, but it’s also undeniable. Introduced in Guardians of the Galaxy in 2014 as a space-faring outlaw adopted as a child and raised by the Ravagers, Chris Pratt’s Peter Quill was quickly established as one of the MCU’s funniest characters. The slightly goofy Star-Lord was set up as the leader of the movie’s titular team, later reprising the role in two direct sequels as well as other movies in the franchise.

Star-Lord’s character development was not the most obvious in the MCU, but it was remarkably well done. His growth throughout the Guardians trilogy sees him go from a somewhat childish figure to a genuine leader, helping to bring those around him together into a cohesive and effective unit. The exploration of Quill’s parentage and relationships proved especially touching, further helping define him as one of the MCU’s best-developed characters.

6. Bucky Barnes Has Been Developed Into The MCU’s Most Underrated Hero

Introduced In: Captain America: The First Avenger (2011)

Despite being presented as more of a sidekick than a true hero in his own right, Bucky Barnes is one of the MCU’s most complex and interesting figures. First introduced as Steve Rogers’ affable best pal, Bucky’s later abduction by Hydra and their subsequent experiments on him saw him become the Winter Soldier, a brainwashed assassin forced to do the bidding of the villainous organization. His reintroduction to the MCU’s modern timeline saw Bucky break free of his conditioning and slowly discover himself as a hero once more.

Bucky’s MCU story has been filled with tragedy. His role as an unwitting pawn of Hydra has seen him seek redemption through his heroics, and he has gone on to form a close bond with other MCU heroes as a result. Developing Bucky as a character was no mean feat considering the weight of his narrative arc, but it’s one that has been incredibly well-executed by Marvel in the MCU.

5. Thor’s Tragic Story Has Made Him A More Well-Rounded Hero

Introduced In: Thor (2011)

There are few figures in the MCU who have lost as much as Thor. Introduced in Phase 1 of the franchise, Thor served as a founding Avenger and is the only character in the MCU to have been given four solo movies during his tenure as a hero. First established as a hard-headed but well-meaning Prince of Asgard, repeated tragedy has turned Thor into a completely different type of hero.

Not only did Thor lose his brother Loki on many occasions, but he also lost both parents in the span of just two movies. Thor then lost his home when he was forced to allow Surtur to destroy Asgard in order to stop his long-lost sister Hela, and the ending of Thor: Love and Thunder also saw the hero lose Jane Foster, his long-term romantic interest. So much loss has transformed Thor into a particularly tragic figure in the MCU, helping to develop his character into an increasingly complex hero along the way.

4. Sam Wilson Has Undergone A Full Hero Transformation

Introduced In: Captain America: The Winter Soldier (2014)

When Sam Wilson was first introduced into the MCU, it was as a supporting character to Chris Evans’ Captain America. Wilson’s lack of abilities was often played for laughs against his super soldier friend, even after he was established as the Falcon, a hero with a technologically advanced wingsuit. Subsequently, Wilson joined the Avengers, and became an increasingly prominent hero within the MCU.

Steve Rogers chose Sam Wilson as his successor, naming him the next Captain America. Sam’s journey to accepting the role saw even more character development, with the Avenger acknowledging his ability to inspire and help others as enough to make him worthy of carrying Rogers’ shield. Sam Wilson’s gradual transformation from a seemingly average man to one of the MCU’s most prominent and relatable figures has been nothing short of excellent and stands out as brilliant character development.

3. Hulk Has Become One Of The MCU’s Most Beloved Characters

Introduced In: The Incredible Hulk (2008)

Hulk, as he was first introduced into the MCU, was a largely underwhelming character. Played by Edward Norton in 2008’s The Incredible Hulk, Bruce Banner was a relatively bland protagonist, and Hulk himself was in dire need of some active character development. When the role was recast for 2012’s The Avengers, Hulk’s character arc truly began, and despite no follow-up solo movie, the hero has become one of the MCU’s greatest characters.

First establishing Banner and Hulk as separate personalities, the MCU explored both. Later, Banner reconciled the two into a single persona, serving as a major milestone for Hulk in the franchise. Despite being introduced as one of the least interesting characters in the MCU, the franchise has seen him develop into one of the most consistently funny and interesting heroes, marking an excellent shift in his characterization.

2. Loki Has Been Developed Into A Particularly Complex Character

Introduced In: Thor (2011)

Loki is undeniably one of the MCU’s most popular characters, which is largely thanks to excellent character development. Originally introduced in 2011’s Thor as a duplicitous villain, Loki went on to feature as the main antagonist of The Avengers. Phase 2 of the MCU saw the franchise begin to explore other aspects of the God of Mischief, fleshing him out as a complex and more well-rounded figure.

Loki’s gradual shift from villain to anti-hero to a reluctantly heroic figure has been well-executed by the MCU. The character development has been so well-written as to be an especially smooth transition, informed as it was by popular opinion on the character’s potential. Tom Hiddleston’s performance as Loki has enabled a much greater exploration of the character, in turn leading to some of the MCU’s best narrative development.

1. Iron Man’s Character Arc Is The MCU’s Most Substantial

Introduced In: Iron Man (2008)

As Iron Man serves as the central figure of the MCU’s Infinity Saga, it’s fair to say that his character arc has been the franchise’s most prominent. Tony Stark’s role as the MCU’s unofficial protagonist saw him take center stage, enabling a substantial piece of character development to unfold across his many appearances in the franchise. First introduced as a self-centered billionaire playboy, Stark’s eventual transition into one of the MCU’s most heroic figures is truly incredible.

The many narrative twists and turns that led to Iron Man’s unforgettable heroic sacrifice in Avengers: Endgame make up perhaps the greatest character arc in the entire franchise. There are few figures as well-developed as Tony Stark, and considering the franchise’s entire journey began with the character, his development feels intrinsically linked to the success of the MCU. Iron Man’s remarkable development into a true hero is by far the most substantial in the Marvel Cinematic Universe and stands out as the best the franchise has yet had to offer.