Black Panther: Wakanda Forever received an initial trailer during Comic-Con International: San Diego, confirming the long-held theory that actor Tenoch Huerta would be portraying a version of Namor and indeed leading his countrymen of Atlantis into battle against Wakanda as in comics.
Well, sorta. Rather than Atlantis, the MCU Namor's roots lie in a different watery realm - that of Talocan, derived from the mythical Aztec realm of Tlālōcān, the domain of the Aztec storm god.
Not only does this switch align with Huerta's own Indigenous Mexican ancestry, it separates Marvel's Namor from DC's Aquaman, whose solo film already brought a comic adaptation of Atlantis to the big screen.
That said, Talocan and Wakanda seem to be going to war just as Atlantis and Wakanda have done in comics - and there's a much deeper (pun intended) history between the two nations than you may realize.
The Lost Kingdom
Though we won't get into too much Marvel Atlantean history (especially since some of what's been shown in comics will undoubtedly change along with the MCU update of Marvel's Atlantis to Talocan), the TL:DR is that much like the real-world myth and the many versions of it you've seen everywhere from animated Disney movies to sci-fi TV shows and beyond, the Marvel Comics kingdom of Atlantis was once a scientifically advanced but decadent nation that was swept under the water but continued to thrive by adapting to life in the ocean.
There are multiple explanations of how Atlantis sank in the Marvel Universe - two of which could be particularly relevant to the events of Black Panther: Wakanda Forever given the preceding MCU films The Eternals and Thor: Love and Thunder.(opens in new tab)
In the more common telling of the sinking of Atlantis, the Celestials are responsible for sending it beneath the waves alongside the Deviant kingdom of Lemuria during an event called the 'Great Cataclysm' when they once wiped the earth of sentient life.
In the other, Zeus and the other Olympian gods - as in the ones who just swore vengeance on "superheroes" in Thor: Love and Thunder - enlisted the Olympian Poseidon to sink Atlantis for attempting to access magic only allowed to the gods.
Either way, since they sank, Atlantis has become an on-again-off-again enemy of the so-called 'surface world,' with their most famous king, Namor the Sub-Mariner, himself acting as both ally and enemy to those who dwell on land over the years.
In fact, he's even been an Avenger - including right now, when he's recently been forced to re-team with Black Panther years after their two nations went to war, and Atlantis nearly wiped Wakanda off the map.
And since that's what we're here to talk about…
Though it was hardly the first time that Namor and Atlantis had declared war on the surface world over the years, the war between Atlantis and Wakanda during the event story Avengers Vs. X-Men (opens in new tab) and its follow-up Infinity (opens in new tab) may have been the most devastating.
As it says in the title, Avengers Vs. X-Men (or AvX as it's often stylized) involves the Avengers and X-Men going to battle over the Phoenix Force, the cosmic entity of life, death, and rebirth that famously possessed Jean Grey during X-Men: The Dark Phoenix Saga (opens in new tab). In AvX, five X-Men - including Namor, himself considered a mutant - each gain a portion of the Phoenix's power.
During the resulting conflict, the empowered X-Men try to remake the world in their image using the power of the Phoenix.(opens in new tab)
The Avengers, not taking kindly to this idea, oppose them, and in one of their battles, Scarlet Witch gravely injures Namor.
As Wanda takes refuge in Wakanda, Namor goes against the other members of the so-called 'Phoenix Five' and launches an all-out Atlantean assault on Wakanda, using the ocean itself to flood and all but level huge portions of the hidden nation.
The Avengers rally around Black Panther, and drive back Namor's forces - but only after great losses in Wakanda.
And though the battle resulted in Namor losing his Phoenix power - and the Avengers technically kinda won the conflict - that was not the end of the war between Wakanda and Atlantis.
Wakanda Strikes Back
In the later event story Infinity, Wakanda strikes back at Atlantis amid a conflict between the Avengers, the Illuminati, and most of the world's other heroes against Thanos and the Black Order as they invade Earth to kill Thanos' secret half-Eternal, half-Inhuman son, Thane.
But while the Illuminati - of which both Namor and Black Panther were then members - are attempting to work together to stave off Thanos, Shuri, who was then ruling monarch of Wakanda, declares an attack on Atlantis to take advantage of Namor's distraction.
Wakanda lays waste to Atlantis much the same way Atlantis previously devastated Wakanda - but Namor isn't willing to take Wakanda's retaliatory attack laying down.(opens in new tab)
So when Thanos comes knocking at Atlantis' door looking for the Infinity Stone which Namor is hiding, Namor lies and sends Thanos and the Black Order to Wakanda - initiating the comic book version of the Battle of Wakanda seen in the film Avengers: Infinity War.
In the course of Infinity and the surrounding conflict between Atlantis and Wakanda, both kingdoms are destroyed by Thanos' armies.
Interestingly enough, Infinity is the same event in which the Terrigen Mists, the substance that gives Inhumans their powers when they're exposed to it, are released into Earth's atmosphere, triggering the comic book version of Kamala Khan's transformation into Ms. Marvel.
And of course, the aftermath of Infinity, in which Multiversal Incursions began threatening the entire Marvel Universe led directly to … say it with us now … Secret Wars, which is of course getting its own movie adaptation as Avengers: Secret Wars to close out the MCU's upcoming Phase 6.
Avengers Vs. X-Men is one of the most impactful Marvel Comics events of all time.