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One major decision in Iron Man defined not just Robert Downey Jr’s hero, but also the MCU itself for the entirety of its runtime thus far. With the MCU timeline being in its seventeenth year – and having plenty of upcoming MCU releases on the horizon – the movie that started it all is in many ways more important now than ever.

Of course, this is partly because Robert Downey Jr. is set to return as Doctor Doom as part of the cast for Avengers: Doomsday – but it’s also because of much more than just that. Iron Man defined the MCU in some ways that are impossible to overstate, particularly through one unusual but undeniably integral choice made regarding the film’s finale.

Iron Man’s Ending Defined The MCU In Several Colossally Important Ways

Looking back now, it’s surreal to note that, in Iron Man’s past, the Marvel hero was regarded as a B-level superhero – someone that had their own share of fans, but who was considered a step below the franchise’s most famous figures. All of that changed thanks to the release of Iron Man itself, cemented by its dramatic ending.

Tony Stark revealing he was Iron Man to the press and public was a major twist for the final moments of the movie, and one that would come to define the hero’s arc – ensuring audiences would be left celebrating, but also left wondering what happens next, setting up for the expansion into both Iron Man 2 and the wider MCU.

Interestingly, this was reportedly one of Robert Downey Jr’s most important improv moments, with the “I am Iron Man” line not initially being planned as part of the film, let alone its dramatic conclusion.

However, it’s hard to imagine a more perfect conclusion to the movie, as it serves to encapsulate the actor’s iteration of Tony Stark perfectly, all while establishing the way in which the MCU would go on to look at adapting its comic source material. As Kevin Feige said on the matter in a 2018 interview with ᴅᴇᴀᴅline:

“Tony Stark not reading off the card and not sticking with the fixed story? Him just blurting out ‘I am Iron Man?’ That seems very much in keeping with who that character is. It just hadn’t been done in the comics before, but it was something very much in keeping with the comics character and what he could have done. I think it did inspire us on all the movies.”

While the concept of public superheroes was by no means first introduced via Iron Man, this likely resonated with audiences as strongly as it did because of how different it promised Iron Man would be to many other recent big superhero film figures, since movies like Batman Begins or the Sam Raimi Spider-Man films hinged around their heroes’ secret idenтιтies.

This not only meant that audiences regarded Iron Man as a breath of fresh air, but also that Iron Man set a precedent for later releases, teeing up for more public superheroes to be unveiled in the MCU, and laying the foundations for things like the Sokovia Accords to be complex MCU matters that effected all heroes differently.

Without Iron Man’s Ending Twist, The MCU Would Be A Different (& Likely Worse) Franchise

First and foremost, Iron Man‘s ending was fascinating in terms of essentially skipping years of the character’s comic history, which saw Tony conceal his secret idenтιтy under the guise that Iron Man was instead working alongside him, oftentimes as his bodyguard. Iron Man‘s results set up the franchise to continue taking this approach, with Feige stating that:

“That success inspired us to go further in the trusting ourselves to find balance of staying true to the comics and the spirit of the comics but not being afraid to adapt and evolve and to change things… It’s a fine line. If you’re changing something for no reason, that’s one thing, but if you’re changing something because you want to double-down on the spirit of who the character is? That’s a change we’ll make.”

The decision to have Tony Stark operate as a public hero also meant Iron Man and Stark were intertwined in a way that ensured viewers who hadn’t known they were one and the same before certainly never forgot, and also set up cornerstones that would go on to define much of the MCU subsequently.

Ultimately, this decision helped pave the way for the Iron Man vs Captain America conflict in Captain America: Civil War, since Iron Man accepting the Sokovia Accords and their requirement to have heroes reveal their secret idenтιтies to the government made more sense given he himself had gone totally public with his idenтιтy years beforehand.

Subsequently, the dissolution of the Avengers had more emotional weight, and their reunion in Avengers: Endgame felt all the more poignant as well. Finally – but perhaps most importantly – the Iron Man ending scene was one of many decisions that made Tony Stark’s Endgame sacrifice hit so hard.

As a hero who’d always sought to protect others and place this above all other priorities – to the point of giving up a secret idenтιтy – Tony Stark giving his life to defeat Thanos was something set up from Iron Man itself onward, with his history of choosing the “sacrifice play” of sorts beginning with this film.

17 Years Later, Iron Man’s Secret Idenтιтy Twist Still Defines The MCU

There are some direct ways Iron Man‘s ending can be seen to have impacted the present day MCU. MCU heroes conventionally are more likely to be public with their idenтιтies than not, and this is approached both in playful ways and in more serious, grounded contexts, mirroring how Stark’s own public hero career as Iron Man unfolded.

Similarly, the MCU is still mirroring the formula Iron Man‘s ending cemented in terms of its approach to lore. Had Iron Man followed the comics more directly in terms of having Tony Stark keep a secret idenтιтy, it’s likely the franchise would have continued to play it “safer” adaptation wise, arguably to its own detriment.

While recent results for the MCU have been more mixed critically and commercially, these installments still speak to the franchise’s attempts to continually reinvent itself and experiment with how it adapts Marvel’s lore while keeping the elements that made audiences first fall in love with it. Kevin Feige suggested this would be the MCU’s eternal mission in 2018, stating that:

“What I love now — 20 movies in — is how fans expect the MCU to change and adapt. They expect us to be inspired by the comics as opposed to being slavishly devoted to them.”

Perhaps the most important way the MCU is still defined by Iron Man‘s secret idenтιтy reveal, though, is in terms of how it influences the franchise’s approach to character arcs. Choosing this unexpected path forward because it suited Stark best led to the character-driven stories we see today, which are insurmountably important in terms of the MCU’s success.

Having heroes and villains make choices that feel authentic and three-dimensional – even when they actively go against what audiences may have expected, and what the comics themselves may have implied would happen – has been crucial historically for the MCU, especially in terms of making viewers feel invested in its stories.

This also goes a long way in terms of helping grow fanbases for many characters, with figures like Loki or Yelena having so many fans partly because they make fascinating decisions that would be hard to predict beforehand. Hopefully, the MCU’s releases will continue to bear the fingerprints of this monumental Iron Man decision for many more years to come.