Warning! SPOILERS for Black AdamThe element Eternium is featured in Black Adam, playing a major role in the story akin to Superman's kryptonite. Dwayne Johnson's debut as Black Adam accomplishes a significant amount of world-building in the DCEU, with Black Adam's large cast of characters including the Justice Society of America and other major DC figures. In addition to the debut of villains like Intergang and Sabbac, along with a huge end-credits cameo, Black Adam also incorporates other big elements from DC Comics.
Among them is the fictional element known as Eternium, which plays a MacGuffin type of role in Black Adam, as well as being the only force in the film to impede the otherwise seemingly impenetrable Black Adam. Eternium has its own backstory in DC lore, which makes its inclusion in Black Adam all the more significant. With Dwayne Johnson having big plans for Black Adam's future in the DCEU, Eternium's introduction in the film could be part of those plans.
What Is Eternium (& How Much Is It Like Kryptonite)?
In the comics, Eternium is created from the shattered pieces of the Rock of Eternity, which is the base of the Council of Wizards, as well as where both Teth-Adam and later Billy Batson (Asher Angel) acquire their powers. As seen in Black Adam, Eternium is heavily sought after by Intergang in their occupation of Kahndaq, along with their pursuit of the Eternium-comprised Crown of Sabbac. On the flip side, Eternium is an element that both Black Adam and Shazam have to steer clear of, with its effects weakening them and nullifying their powers, much in the way that kryptonite counteracts Superman's superpowers.
This happens to Adam early on in the film when he withstands an injury to the torso from an Eternium-filled rocket that blunts Black Adam's immense powers, causing him to collapse. With that said, Adam is able to recover from his Eternium wounds and return to full power after a period of rest, while a long period of direct exposure to green kryptonite can kill Superman.
How Eternium Could Return In Black Adam's DCEU Future
With the introduction of Eternium in Black Adam, the element acting as a counter-agent to Black Adam's (and Shazam's) powers could see it put to use by their respective enemies. One such adversary who seems likely to stock up on Eternium is Amanda Waller (Viola Davis), who warns Black Adam that he is not to transgress his purview of protecting Kahndaq at the end of the movie. Eternium might also have a role to play in Black Adam's building conflict with none other than the Man of Steel himself, with Black Adam's post-credits scene seeing Superman (Henry Cavill) dropping in for a meeting with the newly titled Black Adam.
With Black Adam and Superman having their weaknesses respectively in Eternium and kryptonite, an ally of either of them could deploy the deleterious element in question against their enemy as a tool to tip the scales. Alternatively, Black Adam and Superman's showdown of metahumans would be quite a bit more complicated if either were to resort to tapping into his opponent's weakness themselves. Even so, with Eternium on the table as a way to stop Kahndaq's sworn defender in his tracks, Black Adam's introduction of the element into the DCEU probably hints to Eternium being seen again in the story of Black Adam 2 or beyond.
