No Weapon X yet, but Captain America: Brave New World marks the arrival of adamantium to Earth-616 in a departure from its comic book origins.

The fourth Captain America movie, Captain America: Brave New World, is finally out and has been met with middling critical reviews. Despite that, fans are already dissecting every new character and plot development that’s transpired as they eagerly await The Fantastic Four: First Steps and Thunderbolts. Most intriguing is the introduction of adamantium in this movie, which is fascinating because of how it differs from the comic book lore.

Adamantium is part of the comic book-y, ‘fun first’ science found in the long-running universe. From vibranium to recurring alien threats, the vast Marvel Cinematic Universe takes many elements from Marvel’s take on outer space. That said, the metal that covers Wolverine’s skeleton had an entirely different origin in the comic books and the X-Men movies.

Last year’s Deadpool & Wolverine made sure to partially bring the Fox universe’s (now dubbed Earth-10005) characters into the larger MCU multiverse. There, adamantium is a man-made steel alloy. In the 616 timeline, however, we’ve just found out its origin is as alien as vibranium’s, and Earth’s scientists are considering it an all-new element.

Adamantium in the Marvel Cinematic Universe

(Image credit: Marvel / Disney)

Mild spoilers ahead for Captain America: Brave New World.

Red Hulk’s appearance in the fourth Captain America movie brings back the quite silly Marvel science of gamma rays to the forefront of the MCU. In fact, many would argue it’s more of a sequel to 2008’s The Incredible Hulk than a Captain America movie, despite the title. The main ‘MacGuffin’ of the plot, adamantium, is found on the massive Celestial body that was half-born in the middle of the Indian Ocean at the end of 2021’s Eternals.

Tiamut’s frozen body is now called ‘Celestial Island’ by Earth’s governments, and of course, everyone has rushed to investigate it. With tensions between the Wakandans and the rest of the world rising in recent times due to their strict control over vibranium, many nations see the discovery of adamantium (said to be somehow even stronger and more malleable) as the golden opportunity to remain relevant in the rapidly escalating weapons and technology race. Moreover, with extraterrestrial and augmented threats ever-present, humans are looking for every advantage they can get their hands on.

While Eternals wasn’t a success and the chances of a direct sequel are currently slim, Marvel Studios has found a way to bring a huge part of it back in a way that answers burning questions and sets up the future.

In Captain America: Brave New World, the adamantium is little more than a plot device that gets the story going and sets the stage for new political tensions. Needless to say, evildoers also want to get their hands on it, and while we haven’t seen the 616 iteration of the metal in action yet, we’re fairly sure that it’ll play a huge role in the post-Avengers: Doomsday and Secret Wars saga going forwards.

Adamantium in the comic books

The comic books (and the aforementioned X-Men flicks) introduced adamantium in an entirely different way: It’s a virtually indestructible man-made steel alloy that just isn’t found in nature. The United States government created it, and the composition remains a secret. Moreover, the traditional origins of adamantium depict it as dense and rigid in a way that makes it hard to work with.

Captain America’s shield, partially made of vibranium in the comics, was one of the few objects known to have stopped adamantium. On the other hand, the MCU’s own version of the metal, an actual pure element that happened naturally outside of Earth, has been teased to be highly adaptable and potentially destructive against vibranium armor and weapons. Hokey science explanations aside, it all comes down to narrative needs; this late into the MCU, a ‘more dangerous’ metal was needed, and it all might spell trouble for Wakanda and its closest allies.

The comic books also worked with a number of different versions of adamantium over the years, namely proto-adamantium (the one created to use on Captain America’s first shield), true adamantium (the one present in Wolverine via the Weapon X program), the more cost-effective adamantium steel, and several multiversal variants. In any case, the metal’s origins were always linked to mankind and the mutants, not outer space.

What does adamantium mean for Earth-616’s future?

We know for a fact a new X-Men movie, likely set in the main MCU continuity (aka 616), is happening shortly after Avengers: Secret Wars is released. The question we face now is whether Wolverine will be part of the original roster or not. Moreover, what are the actual chances of Disney and Marvel choosing to keep Hugh Jackman’s now-multiverse-hopping Logan around, maybe even mentoring a new generation of mutants after losing his own elsewhere?

In that case, the Weapon X project wouldn’t factor into the plot at all because there would be no need for another Wolverine. However, adamantium has many uses, and with projects like Armor Wars still waiting to be made, there are plenty of story arcs where it could be used to throw Earth-616 into chaos which doesn’t come from outer space or the multiverse. What about the mutant-hunting Sentinels? We’ve yet to learn about the origin of the mutants in the main continuity despite some multiversal teases, but the public’s reaction to them probably won’t be kind.

A third and final theory that’s quite compatible with the rest is that Doctor Doom, who we’re expecting to be the big multiversal threat in Doomsday, will be making bad use of some of that adamantium when he arrives. Remember when Ultron upgraded himself by using vibranium? If 616’s adamantium is as strong and flexible as it looks, that sounds like a resource that a megalomaniac, multiverse-threatening villain would want to get his hands on. Likewise, the Avengers could gain the upper hand thanks to it, so all bets are off right now.