“Imperius Rex!” is the war cry of the Sub-Mariner (known as Namor to his friends), who greeted comic book fans on Aug. 31, 1939, in Marvel Comics No. 1. (I am aware, my fellow geeks, that Namor was previously seen in a handful of prototypes of Motion Pictures Funnies Weekly, a comic created for movie theaters.)

The Sub-Mariner was one of a parade of characters who followed in the wake of the 1938 arrival of Superman, who had comics publishers scrambling to find their big hit. Other characters premiered in Marvel Comics No. 1, but Namor, whose mother is from the sunken city of Atlantis and whose father is human, arguably has the richest history.

“He was comics’ first antihero,” Mark Waid, a veteran comic book writer and editor, wrote in an email interview. “Namor’s goal wasn’t to rescue kittens or punch criminals — it was to lead an Atlantean army against the air-breathers of America.”

That was true of his origin story, but over the years, Namor , who was created by the writer-artist Bill Everett (who came up with the name from the word Roman, written backward), has also been a hero, a film studio mogul, a corporate tycoon and an environmentalist. His shifting alliances are still explored in comics today. Here are some important issues in his swim-up to his 80th.