When the roster of main characters features the likes of Iron Man and Captain America, it's evident that the Marvel Cinematic Universe has a large number of heroes. The hero of a story is the person who overcomes impossible odds to achieve their journey and, typically, save the day. Any number of characters in the MCU can fulfill the hero role, but there are also a lot of other character archetypes they align with.
In classic literature, specific archetypes have defined roles in a hero's journey. There is the Shadow, the villain the hero must defeat. Each hero can have their own on their journeys, but for the larger MCU, that Shadow is Thanos in the first decade of movies. There are numerous other roles filled, like the Mentor, Shapeshifter, and Creator, and of the Avengers fit right into them.
The Herald: Nick Fury
In the hero's journey, the Herald is the person who gets the journey going. Think of them as the person who gives the hero a clear path, or alerts them to their quest. Nick Fury might not be running into town telling specific heroes that there's a threat on the horizon, but he does fill the role.
Fury has eyes and ears everywhere. He's the kind of person who always has a plan and always has a suspicion of what's going on. Fury is also the person who brings the Avengers together in the first place. It's he who starts the Avengers Initiative and has S.H.I.E.L.D. agents evaluate each of the potential . He provides them with their call to action.
The Mentor: Hawkeye
Most heroes have a Mentor who helps guide them on their journey, which isn't entirely the case with most of the MCU characters. That's because a lot of them have to find their way for themselves, or the scientist that gives them their superpowers ends up dead.
Hawkeye, however, is one of the best cases to fill the Mentor role because he tries to take multiple heroes under his wing. It's Hawkeye who brings Black Widow into S.H.I.E.L.D. instead of eliminating her. He also convinces Wanda Maximoff to be on the side of the Avengers. He works with both of them, but he'll be taking on the real Mentor role in the Disney+ series named for him when Kate Bishop starts training with him.
The Jester: Ant-Man
The Jester is often thought of as little more than comic relief, but that's not necessarily true. While, yes, the Jester is the one usually cracking the one-liners that makes the audience laugh, there's a little more to them than that.
They also tend to be incredibly observant, sometimes even voicing the audience's questions — or criticisms. In some ways, other heroes, like Thor, would also fit the bill, but Ant-Man is probably the most consistent character to fill the role.
The Shapeshifter: Black Widow
When the audience, and even the hero, isn't sure if their ally can be trusted or not, that person is classified as the Shapeshifter. More often than not, they're on the side of good, but it's never easy to tell.
Black Widow, with her assassin background and her spy sensibilities, is the perfect Shapeshifter. In Captain America: The Winter Soldier, Steve spends a good chunk of time not sure if he can trust her. In Captain America: Civil War, she betrays Tony to help Steve and Bucky get away. Black Widow is someone who can play both sides of any conflict because she makes her own choices instead of being blindly loyal. Interestingly, Nebula, Gamora, and Wanda Maximoff also can all fill this archetypal role.
The Outlaw: Captain America
Steve Rogers is a bit of a Boy Scout, right? So, how can he be an Outlaw? An Outlaw doesn't have to be an actual criminal, though Steve does fall into that category when he breaks the Sokovia Accords for his friends.
Instead, an Outlaw is someone who speaks their mind and follows their own moral com, no matter what the heroes or authority figures around them want them to do. They are honest to a fault. Because of the way they skirt the authorities around them, they can wind up in a lot of trouble. Captain America might be the guy who is always willing to make the sacrifice play himself, but he's also the guy who doesn't let anyone tell him what to do unless he agrees with them. He's definitely the Outlaw amongst heroes.
The Explorer: Hulk
To be completely fair to this hero, Bruce Banner is the real Explorer. Hulk becomes one too when Banner develops a way for him to be himself as Hulk.
The Explorer is the epitome of curiosity. They always want to learn more and grow, find ways to better themselves. For Bruce Banner, that gets put on hold for a while because he's so consumed with keeping Hulk at bay. It's Hulk, however, that embraces the curious spirit of an Explorer and takes a Quinjet to the stars instead of sticking around on Earth. It's Bruce Banner who continues scientific research, like helping Tony Stark develop Vision.
The Innocent: Groot
As its name would imply, the Innocent is the archetype of childlike wonder. They are the person who might be a bit naive, who still has a lot to learn about the world around them.
Truthfully, that could very well apply to several MCU heroes in the early stages of their careers, but with the new Groot that is born from the original's sapling at the end of Guardians of the Galaxy, there is a literal Innocent member of the team. He sees the team as his family, not a group of misfits who may or may not be criminals. Groot doesn't understand the larger ramifications of some of the things the team does, but he still helps them along.
The Everyman: Falcon
Most of the heroes come from humble beginnings, but Sam Wilson's Falcon is more aware of that than most. When people want to know what it is he does, he even says at one point, "I do what he does, only slower," about Captain America. Falcon is a veteran who gets pulled into the world of heroes.
He does have military training, and a pretty high tech pair of wings he can use, but at his core, Sam is a regular guy, an Everyman. Falcon is grounded in a way a lot of the heroes in the MCU aren't as he attends therapy sessions for veterans when he's introduced — and even questions whether superheroes have time for breakfast.
The Ruler: Thor
The Ruler can be either a help or a hindrance to the hero, so it might be a little strange to think of Thor filling this particular role. A lot of times, the Ruler isn't necessarily a political or royal leader, but someone in a position of authority who doesn't know the hero's whole story.
The Ruler often has the best of intentions but is blind to the big picture. That is very much the case with Thor. In Thor's first outing in the MCU, though he is the hero, his own ego blinds him to the plight of others. In later outings, he often comes to the Avengers with only half of the picture, believing what he knows to be best and creating friction amongst the group. He even does the same with the Guardians of the Galaxy.
The Creator: Iron Man
Creators tend to be brilliant thinkers. They are the characters who are driven to bring everything they imagine to life. That might mean inventing new machinery or creating new suits of armor to guard the entire world.
No one embodies the Creator more in the MCU than Tony Stark. Tony, even before he's officially Iron Man, is fascinated by technology, and always pushing the boundaries of what he knows to see what else he can make. As Iron Man, Tony uses that drive to protect people, though it doesn't always go the way he envisions, like Ultron becoming a villain. Creators tend to leave a large legacy behind, as Iron Man has done with the likes of War Machine, Spider-Man, and more in the MCU.
