Iron Man 3 may have started laying the groundwork for The Eternals all the way back in 2013. Marvel Studios has a reputation for playing the long game, and eagle-eyed fans scour through the Marvel Cinematic Universe entries in search of Easter eggs, aware that some of them foreshadow future ideas. That means it’s well worth casting our eyes back over the last two-dozen Marvel movies for hints at what’s to come in Phase 4.

So far the Phase 4 slate has been kept largely under wraps, with Marvel president Kevin Feige reluctant to comment until after Avengers: Endgame airs in April. It’s believed the 2020 slate consists of Black Widow and The Eternals, and the latter is a particularly surprising choice, given they’re a pretty deep cut into Marvel lore. In the comics, the Eternals were an evolutionary offshoot of humanity created thousands of years ago. Adding them into the MCU is going to dramatically reshape the history of Marvel’s shared universe.

But is it possible Marvel has already planted the seeds for The Eternals? Surprisingly, there’s one detail in Iron Man 3 that suggests they may well have done.

  • This Page: Iron Man 3’s Extremis Plot and the Origins of the Eternals Page 2: How Iron Man 3 May Have Set Up The Eternals

Extremis Found Gaps In Human DNA

One of Iron Man 3’s most important plot points was the creation of Extremis. This was an advanced form of genetic manipulation created by Maya Hansen and Aldrich Killian, a formula that rewrote a subject’s DNA and harnessed their body’s natural bio-electricity to trigger phenomenal superhuman powers. Over the course of the film, Killian and his Extremis subjects demonstrated superhuman strength and agility, a resistance to injury, remarkable healing powers, and even a strange exothermic ability. This last power could be used to disable an Iron Man armor with just a touch, or to breathe flames like a dragon.

According to Killian, the reason Extremis worked was because he identified a strange gap in the brain near to the somatosensory cortex. “This is an empty slot,” he explained, “and what this tells us is that our mind, our entire DNA in fact, is destined to be upgraded.” Interestingly, Agents of S.H.I.E.L.D. has strongly suggested that Extremis isn’t the only thing that can be slotted into this gap. Hydra developed the Centipede Serum, and while they initially used Extremis, they developed variant strains that incorporated Jiaying’s DNA, their versions of the super-soldier serum, and even sources of Gamma radiation. It’s actually possible that all the MCU’s superhumans gained their powers because something was activated in this mysterious part of the brain, “upgrading” them.

But does an empty slot like this come about by accident? A popular myth suggests that humans only use 10 percent of our brains, but in truth scientists believe every single part of the brain has a purpose - or, at least, had a purpose at some part in our evolutionary history. That makes sense, given natural evolution doesn’t tend to involve waste. So Killian’s discovery is unlikely to be natural; rather, it’s evidence of design. In the MCU, it’s reasonable to extrapolate that human evolution was influenced at some point or another, by forces who intended to “upgrade” the human race at some point in the future.

The Celestials And The Origin Of The Eternals

This is where the Eternals come in. In the comics, over 4 billion years ago the Earth was visited by a cosmic race known as the Celestials. The Celestials were one of the galaxy’s first, and most powerful, alien races; they traveled the cosmos seeking out life, and experimented upon it wherever they found it. They created two entirely new evolutionary offshoots of humanity, the Eternals and the Deviants, who wage a never-ending war against one another. But the mainstream human race was also transformed as a result of Celestial meddling.

According to the comics, the Celestials did something to the human race that changed it utterly, giving humans the potential to develop superhuman powers. The Celestial influence is the reason Steve Rogers could become a super-soldier, T’Challa could ingest a Heart-Shaped Herb and be granted phenomenal power, and Bruce Banner could use Gamma radiation to unleash the Hulk. The comics have established that it’s even the reason a single gene was introduced into humanity, one that would lie dormant for millennia, until it finally gave rise to the mutant race and became known as the X-gene.

An early rumored synopsis for The Eternals has suggested it will be set “millions of years ago,” which essentially means it’s a prequel for the entire MCU. If that’s the case, and if the MCU is following the comic book story, then this will be the tale of how the Celestials first came to Earth and experimented upon humanity. Millennia later, in Iron Man 3, it looks as though Killian has unwittingly found evidence of alien tampering: the empty slot they had created, that could be used to grant superhuman abilities.

Page 2: How Iron Man 3 May Have Set Up The Eternals

How Iron Man 3 May Have Set Up The Eternals

It’s possible Killian’s discovery is even more important than just explaining how humans can acquire superpowers; it may explain how the Celestials created both the Eternals and the Deviants. In the comics, these two races have given birth to some of the most powerful beings in the cosmos - so much so that it’s been hinted they’re somehow tied to Marvel’s various Pantheons of gods. Thanos himself was born on the Eternal colony of Titan, although he was said to possess the “Deviant gene,” which explains his stature and the color of his skin. Meanwhile, the Skrulls are an entire race of Deviants - and all Skrulls possess the power to shapeshift. It’s reasonable to assume the MCU will follow this pattern; after all, Avengers: Infinity War referenced Thanos’ father from the comics, A’Lars.

It’s possible Killian’s “empty slot” is the reason the Eternals and the Deviants are so powerful. Perhaps the key difference between these two races and the normal human race is simply that the Celestials filled the slot with something; not Extremis, not Gamma radiation, not even the super-soldier serum, but something far more potent. The MCU has always prided itself on being a (loosely) science-based universe, and it may have established the pseudo-science behind the Eternals and the Deviants all the way back in 2013.

Did Marvel Intend To Set Up The Eternals In 2013?

Amusingly enough, it’s unlikely Marvel intended this. The studio has rightly gained a reputation for working years ahead, but in truth they’re quite flexible and reactive; just look at how the Phase 3 slate has changed since it was first announced back in 2014. In this case, Killian’s dialogue can’t even be described as an Easter egg -it’s just pseudo-science, an attempt to explain away what Extremis does and why he’s able to create his own super-soldiers.

But that doesn’t mean this comment isn’t important. Killian’s discovery is most certainly evidence that some sort of intelligence shaped the development of humanity in the MCU, and even provides a scientific basis for the existence of the Celestials and the Deviants. Whether this was intentional or not is almost irrelevant; the precedent is set, and that’s all that matters. And if a Cosmic Cube can be retconned into an Infinity Stone, there’s no reason that The Eternals’ roots can’t retroactively be found in Iron Man 3.

More: Every Phase 4 MCU Movie In Development

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