When it comes to Marvel, we like to think of their heroes as a collective group. After all, films such as The Avengers, Captain America: Civil War, Avengers: Infinity War and Avengers: Endgame have all seen numerous members of the team work together in a fresh fight every time. However, while they are all part of a larger picture, sometimes some heroes are closer than others.

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Over the past 11 years, audiences have seen characters grow closer to each other - leading to certain double acts. We now take a look at the best duos the Marvel Cinematic Universe has to offer. Watch out for MCU spoilers, if you're not up to speed yet!

Captain America And Bucky Barnes

Let's start with the first Avenger, then. Captain America and Bucky Barnes weren't always in the middle of a fight. Back when the first film featuring the duo hit screens in 2011, they were going growing up in Brooklyn. Steve Rogers was weak, being beaten by people bigger than himself with Bucky often having to intervene. However, when the power roles reversed upon Rogers taking the Super Soldier Serum, they then fought together before Barnes' apparent death saw their time together cruelly cut short.

Upon learning that Bucky was alive in Captain: America The Winter Soldier, Steve spent a long time attempting to coerce his friend into remembering his life before Hydra had experimented on him. He then spent a while tracking him down and then fighting by his side against Tony Stark during the sequel. They both held their own against Iron Man, and their fondness for each other is made clear with a final hug at the conclusion of Avengers: Endgame.

Captain America And Falcon

Bucky isn't Cap's only friend throughout the MCU. The World War II veteran also strikes up a relationship with Sam Wilson during the events of Winter Soldier, where they team up to prevent Hydra agent and S.H.I.E.L.D. traitor Alexander Pierce from blowing the world apart. From there, they go from strength to strength, teaming up to fight against Iron Man and his team of Avengers at Berlin airport in Captain America: Civil War.

Steve takes Sam, aka the Falcon, under his wing throughout the series. It makes for a hard-hitting moment in Avengers: Endgame when the Falcon's voice filters through into Cap's earpiece, confirming he and the rest of the gang were back from the dead and ready to fight against Thanos. There is also a passing of the guard at the very end of the film, with Sam trusted to be the new shield bearer going forth. Their story ends on a touching note.

Thor And Loki

Thor and Loki have an enthralling relationship throughout the series, mostly due to the mischievous Loki's ways. In their first film together in 2011, they spend the majority of their screen time facing off against each other. However, they grow closer through the years, teaming up in the conclusion of Thor: The Dark World and then fighting side by side against their villainous sister Hela in the sequel.

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Every director also seems to succeed in giving the relationship multiple layers. There are amusing moments (such as the 'no help' plan devised in Thor: Ragnarok) and emotional moments, such as Loki's nod to Odin shortly before his death during the early stages of Avengers: Infinity War. While Quicksilver and Scarlet Witch are interesting siblings, the Gods of Thunder and Mischief are undoubtedly the greatest of the series so far.

Iron Man And War Machine

When it comes to Tony Stark's relationship with Colonel James Rhodes, the only thing that has really changed since the first Iron Man film is the switch from Terrence Howard to Don Cheadle. That film sees the pair establish a good working relationship and they never look back, with War Machine sticking by Stark right up until his death in the year 2023.

Prior to working together to undo Thanos' snap, they had joined forces on multiple occasions - winning the majority. Obadiah Stane, Ultron and more are all taken down with them involved in the fray, while Rhodes also chooses to stand by Stark during the billionaire's fight against Captain America. They are both involved in battles against Thanos, in Wakanda and at the Avengers compound itself, despite War Machine being paralysed following the showdown with Cap. When Stark sacrifices himself, Cheadle's character is stood looking mournful at the funeral, and he will be among those who will no doubt struggle in the aftermath of the playboy's passing.

Hawkeye And Black Widow

Black Widow and Hawkeye

Like Iron Man and War Machine, there's another double act within the core group. Jeremy Renner's Hawkeye and Scarlett Johansson's Black Widow are exactly that, with their relationship spanning years and ending in the most heartbreaking of circumstances.

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Hawkeye and Black Widow have history from Budapest, something that is referenced throughout the series but never elaborated on. When Clint Barton invites the other Avengers to his house amid their battle to stop Ultron from destroying the planet in 2015, Natasha Romanoff is already familiar with the marksman's family and even suggests they name their third child in her honour. She never has a family of her own and it is her fondness for Barton's own that leads her into sacrificing herself for the good of securing the Soul Stone in Avengers: Endgame. A selfless gesture, and the way Hawkeye tried to give up his life instead spoke volumes about how close they were.

Rocket And Groot

Only the MCU can take a raccoon and a tree, put them together and make audiences crave more and more of their relationship. But Rocket Racoon and Groot forge a terrific partnership during their films together and, despite being completely different species, have an emotional bond throughout the course of their story.

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Rocket is left heartbroken when adult Groot protects the gang to his peril in the first Guardians of the Galaxy outing. He is similarly distraught when, having raised his plant friend to teenage form, he then witnesses Groot turn to dust when Thanos eliminates half of the universe in Infinity War. The duo then fight by side once again when Hulk brings everybody back in Avengers: Endgame, and we expect them to be back to their bickering selves whenever Guardians of the Galaxy Vol. 3 comes out.

Rocket And Thor

Like Captain America, Rocket isn't alone in being involved in more than one double act. We also see the racoon interact with Thor to brilliant effect during Avengers: Infinity War, with the two characters striking up an immediate connection after the Guardians had rescued the wounded God of Thunder in space. Together, the duo team up go to Nidavellir where, with a little assistance from Groot, they create the weapon Stormbreaker, which, at the time, represents their best chance of stopping Thanos.

Thor and Rocket both land on Wakanda alongside Groot for the film's finale and, though they fail to stop the deaths of millions, they team up again in Avengers: Endgame. There's a poignant moment where Rocket tempts his heartbroken friend into returning to battle early on, with the God of Thunder previously going off the rails. Together they help recover the Reality Stone and play a key role in bringing everybody back to life during the movie.

Scarlet Witch And Vision

Rumours are that Scarlet Witch and Vision will get their own TV show, despite the latter appearing to still be dead following the events of Avengers: Endgame. So far, their relationship has certainly come with plenty of bumps in the road. Firstly, they seemed to be getting along just fine during Captain America: Civil War, only for the split in the group to come between them as well. Elizabeth Olsen's character buries Paul Bettany's under an entire building and the duo face off before ultimately putting their differences aside.

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In Avengers: Infinity War, we see their relationship has been taken up a notch during the time between both movies. The couple are romantically involved, and Vision has even reverted to human form in what looks like a greater effort to fit in. We see them both use their powers to fight Corvus Glaive and Proxima Midnight at Edinburgh train station. The duo always provide awesome action sequences; we hope to see more of both characters over on Disney's streaming service when it launches later this year.

Gamora And Nebula

When it comes to Gamora and Nebula, to say they have a turbulent relationship throughout the series would be putting it mildly. In fact, we've nearly lost track of the amount of times they have faced off and nearly killed each other. However, for that reason, they make a blockbuster double act and, at the time of writing, their journey has been taken in many unexpected directions.

Prior to the release of Guardians of the Galaxy 2, we had seen the two sisters lock horns only to seemingly put their differences aside. In the movie, the duo stay on the same side for good. Gamora and Nebula grow so close that the latter even forgets about her loyalty to Thanos, siding against the mad Titan during their epic showdown on the monster's home planet. They then team up in Avengers: Endgame, with Nebula even killing her former self to stop her from slaying Gamora out of anger at her sibling's treachery. There could yet be more to come in Guardians 3.

Tony Stark And Peter Parker

Of all the duos in the MCU, it is hard to find a more popular partnership than Iron Man and Peter Parker. They first meet in Captain America: Civil War, where Tony Stark recruits the teenager to help take down Steve Rogers. The chemistry between Robert Downey Jr and Tom Holland is bang on as they exchange jokes and quips, setting the stage for the emotional scenes that would come further down the line.

Spider-Man: Homecoming saw Tony adopt the role of mentor regarding Spider-Man. There were tears aplenty when, in the following movie, the webslinger is dusted in front of his role model, managing to muster a devastating apology before fading away. In Avengers: Endgame, we see Tony decide to help the rest of the team on their 'time heist' because he feels remorse at how he was unable to save the schoolboy. The two superheroes get one final hug and Peter is there to utter words of comfort to Iron Man as he dies following his snap at the end of the movie. He is also there for the funeral, and trailers for Spider-Man: Far From Home suggests the webhead will find the death of his friend tough to get over.

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