Avengers

The Asgardian Loki encounters the Other, the leader of an extraterrestrial race known as the Chitauri. In exchange for retrieving the Tesseract,2 a powerful energy source of unknown potential, the Other promises Loki an army with which he can subjugate Earth. Nick Fury, director of the espionage agency S.H.I.E.L.D., and his lieutenant Agent Maria Hill arrive at a remote research facility during an evacuation, where physicist Dr. Erik Selvig is leading a research team experimenting on the Tesseract. Agent Phil Coulson explains that the object has begun radiating an unusual form of energy. The Tesseract suddenly activates and opens a wormhole, allowing Loki to reach Earth. Loki takes the Tesseract and uses his scepter to enslave Selvig and several agents, including Clint Barton, to aid him in his getaway.
In response to the attack, Fury reactivates the "Avengers Initiative". Agent Natasha Romanoff is sent to Calcutta to recruit Dr. Bruce Banner to trace the Tesseract through its gamma radiation emissions. Coulson visits Tony Stark to have him review Selvig's research, and Fury approaches Steve Rogers with an assignment to retrieve the Tesseract.
In Stuttgart, Barton steals iridium needed to stabilize the Tesseract's power while Loki causes a distraction, leading to a confrontation with Rogers, Stark, and Romanoff that ends with Loki's surrender. While Loki is being escorted to S.H.I.E.L.D., Thor, his adoptive brother, arrives and frees him, hoping to convince him to abandon his plan and return to Asgard. After a confrontation with Stark and Rogers, Thor agrees to take Loki to S.H.I.E.L.D.'s flying aircraft carrier, the Helicarrier. There Loki is imprisoned while Banner and Stark attempt to locate the Tesseract.
The Avengers become divided, both over how to approach Loki and the revelation that S.H.I.E.L.D. plans to harness the Tesseract to develop weapons as a deterrent against hostile extraterrestrials. As the group argues, Barton and Loki's other possessed agents attack the Helicarrier, disabling its engines in flight and causing Banner to transform into the Hulk. Stark and Rogers try to restart the damaged engine, and Thor attempts to stop the Hulk's rampage. Romanoff fights Barton, and knocks him unconscious, breaking Loki's mind control. Loki escapes after killing Coulson and ejecting Thor from the airship, while the Hulk falls to the ground after attacking a S.H.I.E.L.D. fighter jet. Fury uses Coulson's death to motivate the Avengers into working as a team. Stark and Rogers realize that for Loki, simply defeating them will not be enough; he needs to overpower them publicly to validate himself as ruler of Earth. Loki uses the Tesseract, in conjunction with a device Selvig built, to open a wormhole above Stark Tower to the Chitauri fleet in space, launching his invasion.
The Avengers rally in defense of New York City, the wormhole's location, but quickly realize they will be overwhelmed as wave after wave of Chitauri descend upon Earth. Banner arrives and transforms into the Hulk, and together he, Rogers, Stark, Thor, Barton, and Romanoff battle the Chitauri while evacuating civilians. The Hulk finds Loki and beats him into submission. Romanoff makes her way to the wormhole generator, where Selvig, freed of Loki's control, reveals that Loki's scepter can be used to shut down the generator. Meanwhile, Fury's superiors attempt to end the invasion by launching a nuclear missile at Manhattan. Stark intercepts the missile and takes it through the wormhole toward the Chitauri fleet. The missile detonates, destroying the Chitauri mothership and disabling their forces on Earth. Stark's suit runs out of power, and he falls back through the wormhole just as Romanoff closes it. Stark goes into freefall, but the Hulk saves him from crashing to the ground. In the aftermath, Thor returns Loki and the Tesseract to Asgard. Fury expresses confidence that the Avengers will return if and when they are needed.

Robert Downey, Jr. as Tony Stark / Iron Man:
A self-described genius, billionaire, playboy, and philanthropist with an electromechanical suit of armor of his own invention. Downey was cast as part of his four-picture deal with Marvel Studios, which includes Iron Man 2 and The Avengers. Downey said that he initially pushed Whedon to make Stark the lead: "Well, I said, 'I need to be in the opening sequence. I don't know what you're thinking, but Tony needs to drive this thing.' He was like, 'Okay, let's try that.' We tried it and it didn't work, because this is a different sort of thing, the story and the idea and the theme is the theme, and everybody is just an arm of the octopus." About the character's evolution from previous films, Downey said, "In Iron Man, which was an origin story, he was his own epiphany and redemption of sorts. Iron Man 2 is all about not being an island, dealing with legacy issues and making space for others. . . In The Avengers, he's throwing it down with the others".

Chris Evans as Steve Rogers / Captain America:
A World War II veteran who was enhanced to the peak of human physicality by an experimental serum and frozen in suspended animation before waking up in the modern world. Evans was cast as part of a deal to star in three Marvel films, in addition to The Avengers. Evans said that Steve Rogers is much darker in The Avengers: "It's just about him trying to come to terms with the modern world. You've got to imagine, it's enough of a shock to accept the fact that you're in a completely different time, but everybody you know is dead. Everybody you cared about. . . He was a soldier, obviously, everybody he went to battle with, all of his brothers in arms, they're all dead. He's just lonely. I think in the beginning it's a fish-out-of-water scene, and it's tough. It's a tough pill for him to swallow. Then comes trying to find a balance with the modern world." Regarding the dynamic between Rogers and Tony Stark, Evans said, "I think there's certainly a dichotomy—this kind of friction between myself and Tony Stark, they're polar opposites. One guy is flash and spotlight and smooth, and the other guy is selfless and in the shadows and kind of quiet and they have to get along. They explore that, and it's pretty fun."

Mark Ruffalo as Dr. Bruce Banner / Hulk:
A genius scientist who, because of exposure to gamma radiation, transforms into a monster when enraged or agitated. Ruffalo, who was considered to play Banner in The Incredible Hulk before Edward Norton took the role, was cast after negotiations between Marvel and Norton broke down. About replacing Norton, Ruffalo said, "I'm a friend of Ed's, and yeah, that wasn't a great way for all that to go down. But the way I see it is that Ed has bequeathed this part to me. I look at it as my generation's Hamlet." About the character, he said, "He's a guy struggling with two sides of himself—the dark and the light—and everything he does in his life is filtered through issues of control. I grew up on the Bill Bixby TV series, which I thought was a really nuanced and real human way to look at the Hulk. I like that the part has those qualities". In October 2014, Norton claimed he chose never to play Hulk again because he "wanted more diversity" with his career, and did not want to be associated with only one character. Regarding the Hulk's place on the team, Ruffalo said, "He's like the teammate none of them are sure they want on their team. He's a loose cannon. It's like, 'Just throw a grenade in the middle of the group and let's hope it turns out well!" This is the first production in which the actor playing Banner also plays the Hulk. Ruffalo told New York magazine, "I'm really excited. No one's ever played the Hulk exactly; they've always done CGI. They're going to do the Avatar stop-action, stop-motion capture. So I'll actually play the Hulk. That'll be fun". The 3D model used to create the Hulk's body was modeled after Long Island bodybuilder and male stripper Steve Romm, while the Hulk's face was modeled after Ruffalo. To create the Hulk's voice, Ruffalo's voice was blended with those of Lou Ferrigno and others; however, the Hulk's only speaking line ("Puny god.") was provided solely by Ruffalo.

Chris Hemsworth as Thor:
The crown prince of Asgard, based on the Norse mythological deity of the same name. Hemsworth was cast as part of a multiple movie deal. He had previously worked with Joss Whedon on The Cabin in the Woods. Hemsworth said that he was able to maintain the strength he built up for Thor by increasing his food intake, consisting of chicken breasts, fish, steak, and eggs every day. When asked exactly how much, Hemsworth said, "My body weight in protein pretty much!" He remarked that Thor's motivation "is much more of a personal one, in the sense that it's his brother that is stirring things up. Whereas everyone else, it's some bad guy who they've gotta take down. It's a different approach for me, or for Thor. He's constantly having to battle the greater good and what he should do vs. it's his little brother there. . . I've been frustrated with my brothers at times, or family, but I'm the only one who is allowed to be angry at them. There's a bit of that."

Scarlett Johansson as Natasha Romanoff / Black Widow:
A highly trained spy working for S.H.I.E.L.D. About the character and her relationship with Hawkeye, Johansson said, "Our characters have a long history. They've fought together for a long time in a lot of battles in many different countries. We're the two members of this avenging group who are skilled warriors – we have no superpowers. Black Widow is definitely one of the team, though. She's not in the cast simply to be a romantic foil or eye candy. She's there to fight, so I never felt like I was the only girl. We all have our various skills and it feels equal". Regarding her training, Johansson said, "Even though Iron Man 2 was 'one-for-them,' I'd never done anything like that before. I'd never been physically driven in something, or a part of something so big. For The Avengers, I've spent so many months training with our stunt team, and fighting all the other actors, it's crazy. I do nothing but fight—all the time."

Jeremy Renner as Clint Barton / Hawkeye:
A master archer working as an agent for S.H.I.E.L.D. Renner said it was a very physical role and that he trained physically and practiced archery as much as possible in preparation. About the role, Renner said, "When I saw Iron Man, I thought that was a really kick-ass approach to superheroes. Then they told me about this Hawkeye character, and I liked how he wasn't really a superhero; he's just a guy with a high skill set. I could connect to that." Regarding Hawkeye's sniper mentality, Renner said, "It's a lonely game. He's an outcast. His only connection is to Scarlett's character, Natasha. It's like a left hand/right hand thing. They coexist, and you need them both, especially when it comes to a physical mission." Renner said Hawkeye is not insecure about his humanity. "Quite the opposite, he's the only one who can really take down the Hulk with his [tranquilizer-tipped] arrows. He knows his limitations. But when it comes down to it, there has to be a sense of confidence in any superhero."

Tom Hiddleston as Loki:
Thor's adoptive brother and nemesis, based on the Norse mythological deity of the same name. About his character's evolution from the film Thor, Hiddleston said, "I think the Loki we see in The Avengers is further advanced. You have to ask yourself the question: How pleasant an experience is it disappearing into a wormhole that has been created by some kind of super nuclear explosion of his own making? So I think by the time Loki shows up in The Avengers, he's seen a few things." About Loki's motivations, Hiddleston said, "At the beginning of The Avengers, he comes to Earth to subjugate it and his idea is to rule the human race as their king. And like all the delusional autocrats of human history, he thinks this is a great idea because if everyone is busy worshipping him, there will be no wars so he will create some kind of world peace by ruling them as a tyrant. But he is also kind of deluded in the fact that he thinks unlimited power will give him self-respect, so I haven't let go of the fact that he is still motivated by this terrible jealousy and kind of spiritual desolation".

Clark Gregg as Phil Coulson:
An agent with S.H.I.E.L.D. who oversees many of the division's field operations. Gregg was cast as part of a multi-picture deal with Marvel. Gregg said his role was expanded in The Avengers: " Agent Coulson had become in terms of the import of this particular story, and how important his job is in bringing the Avengers together, it kind of felt a little surreal, like somebody was playing a prank and that wasn't the real script. But it wasn't, it was the real thing, I got to show up and do that stuff, and it felt like such an amazing payoff to what the journey had been and the fact I had been doing it for five years." Gregg said Whedon provided insight into his character's backstory, particularly about Coulson being a fan of Captain America.

Cobie Smulders as Maria Hill:
A high-ranking agent with S.H.I.E.L.D. who works closely with Jackson's Nick Fury. Smulders, whom Joss Whedon once considered for his unproduced live-action Wonder Woman film, was selected from a short list of potential actresses including Morena Baccarin. Smulders' deal would integrate her into nine films. Regarding her preparation, Smulders said, "I hired this amazing black-ops trainer to teach me how to hold a gun, take me to a shooting range, how to hit, how to hold myself, how to walk and basically how to look. I don't do a ton of fighting in the movie, which is why I wasn't offered a trainer, but I wanted to look like I had the ability to." On relating to the character, Smulders said, "I can relate to her being a mom and being a businesswoman and trying to work full-time and raising a family and having a career. We're asked to do a lot of things these days. I feel she is just all about her job and keeping things going."

Stellan Skarsgård as Dr. Erik Selvig:
An astrophysicist and a friend of Thor under Loki's control, who is studying the Tesseract's power. Regarding Loki's control over Selvig, Skarsgård said, "Well with the scene we did in Thor, it was like Loki, one way or the other, entered Erik's mind. And in Avengers, you will see more clarity in how Loki is using Erik's mind." About his role, he said, " is of importance but the size of the role is not big."

Samuel L. Jackson as Nick Fury:
The director of S.H.I.E.L.D., who was revealed in previous films to be coordinating the "Avengers Initiative". Jackson was brought to the project with a deal containing an option to play the character in up to nine Marvel films. Jackson said he does more in The Avengers than in any of the previous films: "You don't have to wait until the end of the movie to see me". About the role, Jackson said, "It's always good to play somebody is a positive in society as opposed to somebody who is a negative. . . I tried to make him as honest to the story and as honest to what real-life would seem." Jackson compared the character to Ordell in Jackie Brown, calling him "a nice guy to hang out with. You just don't want to cross him".

http://en.wikipedia.org/wiki/The_Avengers_(2012_film)