The question of if Namor is indeed a villain is one of the most anticipated aspects of Black Panther: Wakanda Forever. In his interactions with Queen Ramonda, Shuri, and the rest of T'Challa's inner circle, he is rather hostile, with M'Baku even claiming he is a god. The initial trailer for the film, though, makes it seem like Namor isn't completely wicked.
It is possible that Prince Namor the Sub-Mariner is not the true antagonist of "Black Panther: Wakanda Forever." Namor the Sub-Mariner, one of Marvel's oldest and most well-established characters, is finally making his debut in the Marvel Cinematic Universe (MCU). Namor, who is portrayed by Tenoch Huerta in the Marvel Cinematic Universe, has been redesigned to differentiate him from Aquaman, who is portrayed by Jason Momoa in the DC Extended Universe. Instead of being the ruler of Atlantis, he is now the king of Talocan, which is an underwater kingdom that is located off the coast of South America. Huerta asserts that Namor is more of a villain, even though he will undoubtedly pose a threat to the Wakandans. This is an astonishing assertion, considering that the promotional materials for Black Panther: Wakanda Forever have established that Namor will destroy Wakanda.
This concept was taken from the Avengers Vs. X-Men crossover storyline that took place in the comics in 2012, in which Namor was corrupted by a supernatural power known as the Phoenix. All of Namor's less admirable qualities were accentuated after he came into contact with the Phoenix, which culminated in a devastating assault on Wakanda, which served as a sanctuary for the Avengers at the time. After receiving an increase in his power, Namor flooded Wakanda, causing widespread destruction across the fictitious African nation and setting the stage for a protracted and bloody conflict between the Black Panther's homeland and his kingdom. It is reasonable to assume that the Sub-Mariner's powers will be somehow enhanced in Black Panther: Wakanda Forever, allowing him to wreak havoc on Wakanda. This is because Wakanda is completely landlocked. If this is the case, then Namor could very well be manipulated, just as he was in the comics; however, rather than being under the influence of the Phoenix Force, he could instead be controlled by the Serpent Crown. And, remember he was called "The feather serpent god" which gives us a hint that that is where it draws his extra in the promotional video. This further asserts the claim that the crown might just be the ruler.