Sure, Avengers 5 seems a long way off with no announced release date so far, but that just leaves more time for speculation. This indefinite wait is well-spent poring through past Marvel Comics looking for characters who haven’t appeared in the more than 20 films released so far. So where better to look than all the way back to Marvel Comics #1?
Namor the Sub-Mariner was one of the first superheroes introduced to the Marvel Universe, but “superhero” may not be the right word. Namor was introduced in 1939 as a “man of the deep” with the power of flight, super-speed, and super-strength. A parallel could be drawn to DC’s Aquaman, as they both reside in Atlantis, can communicate with marine life, and breathe underwater, but he’s more like DC antihero Black Adam. (For the record, Aquaman first appeared two years later in 1941’s More Fun Comics #73.)
Over the course of decades of comic appearances, Namor fought Nazis alongside Captain America, suffered amnesia and was saved by The Fantastic Four, and was informed by Charles Xavier that he was in fact a mutant. He both fought with the Avengers and against the Avengers, with the X-Men and against the X-Men. His loyalties shifted from issue to issue.