One of the most interesting aspects of Namor is how resistant it is. As a half-Atlantean, half-human hybrid in the comics, he is a godlike individual, with super strength, durability, and speed, which has a lot to do with him being a mutant. Coincidentally, the Marvel Cinematic Universe takes advantage of all of these traits, painting him as their first mutant yet, thanks to a vibranium serum in the 16th century.
This changed his genetic makeup, transforming him into King Talokan when he was finally born to rule the underwater kingdom. It’s true that he’s a far cry from the comic book source material, but still, the comic and MCU versions of Namor are wary of the surface world. Namor’s characterization and spirit are always evident in every medium. Ironically, while Black Panther: Wakanda Forever highlighted another great strength of the character, Namor the Submarine: Conquered Shores (by Christopher Cantwell, Pasqual Ferry, Matt Hollingsworth, and VC’s Joe Caramagna) ends up painting this very element as a major weakness.
Black Panther: Wakanda ForeverNamor needs water
In the movie, Shuri desperately tries to defeat Namor in order to save her nation from his wrath. Over time, she realizes that she has to go back to the water to recharge after exerting herself. Basically, the water acts as her fuel, allowing her to return to the surface to fight again.
This is also why Shuri prepares her ship to turn it into an evaporation chamber. She eventually catches the mutant, heat beats it, and dries it dry. This helps the new Panther defeat Namor on a deserted island, and he realizes that once he’s out of water, he’s already defeated. In battle, Shuri even cuts the wings from her ankles, which ends with him giving in to her and forging a truce with her Talokan empire.
Namor: Conquered Shores Makes water a defect
On the contrary, number 2 of conquered coasts, a more altruistic Namor is trying to save the surface world after the Kree made the atmosphere toxic and melted all the ice caps. He attempts to fly to find Jim Hammond/Human Torch, to use as a fuel source to restart society, but struggles in midair. It turns out that all that time he spent in the water made him unable to adapt. His aged wings no longer react to air because they are used to the ocean.
Thus, this same sea that revitalizes him has caused this aspect of the warrior to stop working. He can fly, but not for long or too high, causing Jim to escape and Namor to fall back into the water. Granted, he loves the aquatic realm of his, but this doesn’t bode well if he has to fight on the surface. His wings, after all, allow him to move faster than normal, avoid being attacked, and help him be more efficient, as the movie shows. But now, with a journey to find Doctor Doom looming, the introduction of water reduced the effectiveness of him, acting as a double-edged sword of nature.