As the still-untitled Avengers 4 draws ever closer, so does the end of the third phase of the Marvel Cinematic Universe. It's a major turning point, the largest Marvel Studios has faced since it debuted their very first epic team-up in The Avengers, and raises a lot of questions. While some sequels are already in the works and the debut of Captain Marvel in 2018 provide some sense of direction, there's still a lot of questions swirling around what the future holds for the longest-running superhero franchise ever put to film. There's one character who should clearly be part of whatever comes next though: Namor the Sub-Mariner.

There are potential problems with Namor, of course. Earlier this year Marvel boss Kevin Feige admitted that the rights surrounding the character, which had previously been sold to Universal Studios, were "complicated." That's a question for lawyers and money men, folks at Disney who already managed to recapture Spider-Man from Sony and look ready to regain all of the properties held by Fox. With near miracles like that accomplished, it's reasonable to assume that Namor can still join other Marvel Studios heroes on the big screen.

So with that assumption in mind, there's a strong case to be made that Namor is one of the essential unadapted characters who could perfectly frame the future of the Marvel universe on the big screen.

The End of an Era

The most important consideration for Kevin Feige and the rest of Marvel Studios' leadership is how to set the story moving forward. In the wake of Avengers 4, the franchise will have accomplished one of the most impressive feats in Hollywood history and needs to avoid any deflated expectations moving forward. With rumors swirling about the departure of Chris Evans as Captain America and many other actors either completing their contracts or aging out of their roles, now is the time for new blood.

This drive for fresh heroes and ideas is being led by Captain Marvel, who will be part of Avengers 4 in what seems to be a "passing of the torch" moment. One character does not make a movement though. Namor the Sub-Mariner brings a lot of similar strengths to the screen. He is a character with a rich history in Marvel Comics and capable of either handling his own film or playing a notable supporting role, as hero or villain, in another movie. He brings a backstory that offers lots of new stories and settings for Marvel Studios to explore, and a look and attitude unlike anything Marvel has brought to life so far. Namor is a perfect character to assure audiences everywhere that Phase Three wasn't really the end, and that even greater things are on the way.

Return of the Fox Properties

The greatest source of speculation about what comes next at Marvel Studios centers around the return of properties currently controlled by Fox, most notably the Fantastic Four and X-Men. As Disney's acquisition of their rival is finalized, a lot of plans must be put on hold until signatures can be placed on the appropriate lines. That means now is the perfect time to stage the eventual arrival of both mutants and imaginauts to Marvel Studios, and Namor is a character with deep ties to both teams.

While Namor first appeared in the Golden Age, he was brought into the connected Marvel universe in the pages of Fantastic Four #4 when Johnny Storm discovered him as a homeless man who had lost his memory. He quickly developed into one of the team's most complex adversaries, often playing the role of a villain as he threatened New York City or teamed up with Dr. Doom. However, his affection for Susan Storm and noble nature prevented him from ever descending to the role of a clear bad guy. Whether it's as a reluctant ally or initial antagonist, Namor is perfectly situated to provide a welcome mat for the Fantastic Four's return home.

Later in his publication career, Namor was revealed to be one of Earth's earliest mutants, subsequently tying his fate to that of the X-Men. He is currently a member of Jean Grey's team in X-Men Red and has often provided safe harbor for mutants under threat. If Marvel Studios want to maintain Namor's X-gene, then he could introduce the concept of mutants to the movies before the X-Men arrive for another reboot.

A Perfectly Imperfect Hero

There are a lot of reasons to bring Namor into the Marvel Cinematic Universe. He helps to set a new stage in the wake of big events and departing characters. He provides an introduction for both the Fantastic Four and the X-Men. However, the most important reason that now is the perfect time to introduce Namor is that he is one of the best Marvel characters yet to be adapted to film. We recently made the case that Namor is one of the most Marvel characters around, due to both his history and personality, and he's overdue in joining his fellow superheroes on the big screen.

No matter how Feige and his colleagues decide to approach this matter, Namor is a very malleable individual capable of playing many roles. He can by a sympathetic antagonist, a reluctant ally, or the hero of his own story, possibly featuring in all three roles as the movies of future Marvel phases roll out. His complex connections to humanity and an immense undersea kingdom provide lots of story fodder while his own aloof posture and angry attitude contain plenty of dramatic potential.

Putting aside the all-important matter of casting, there has never been a better time to introduce Namor than this very moment. He brings unlimited strengths to the franchise as it currently stands and with all of the future possibilities that will soon become real. More than any other name that can be suggested, Namor is the hero left on the books with the most potential. When Thanos has been defeated, Marvel Studios will be in need of some new heroes, and few stand with more pride than Namor the Sub-Mariner.