His name is not pronounced 'submariner', but rather as 'sub-maar-inner'.
The Sub-Mariner was created by artist-writer Bill Everett, first appearing in Marvel Comics #1, cover dated October 1939. This was the very first comic book published by Timely Comics, who would eventually become known as Marvel Comics — so now you know where the name came from.
Along with the mis-named Human Torch (a synthetic robot) and the juiced Captain America who was injected with chemicals to become a Yankee Doodle fighting machine, the Sub-Mariner was one of the 1940s most popular characters ever.
Everett says he was inspired to create Subby from reading Cooleridge's famous poem, The Rime of the Ancient Mariner, a poem I love so much I can quote it as easily as any from Alice in Wonderland.
Not quite human, Namor is the mutant son of a human sea captain and a princess of the undersea kingdom of Atlantis. Namor/Sub-mariner has super-strength and the aquatic abilities of the made-up Homo mermanus race, as well as the mutant ability of flight, along with other superhuman powers.
He is the first Marvel mutant to appear in comics regardless of their revisionist history to make Wolverine the first.
And, despite Batman and Wolverine being a bad-ass, Sub-Mariner was the first comic book anti-hero.
So... who is this Marvel mutant, and why isn't he in any Marvel movie treatments? No clue.
Along with Marvel Comics (later known as Marvel Mystery Comics with issue #2), the Sub-mariner also appeared in his own Sub-Mariner Comics... which is what I am looking at today.
Yes, the Japanese are shorter in stature, but the comic books show the Sub-Mariner as unearthly huge, which combined with his demonic looks, triangular face and pointy ears, it was no wonder that when the WWII ended kids weren't that interested in a guy that looks evil battling simple criminals...
By the way... in the Fantastic Four #4, the new (human) version of The Human Torch finds Namor as a beadred homeless guy, shaves him and helps him get his memory and thus his kingdom back. Though the kingdom was destroyed by nuclear weapons, and so he now has a real reason to hate all Homo sapiens sapiens.
I want you to know that I am doing all of this from memory. I've owned Fantastic Four #2, and owned every Avengers books from #1-300—except for #4... but have certainly read reprints of these classic stories. I sold #1, but still own the rest.
Anyhow.. although the Sub-Mariner did originally take on the Germans during the early stages of WWII, as soon as Japan hit Pear Harbor, having a water-based super-hero was the best way to take on the Japanese who lived so very far away... and... if he wanted to take on any Japanese planes, he did also possess tiny wings on his ankles that someone didn't cause him any difficulties in flying even if they were wet.
The Sub-Mariner is still a popular Marvel Comics character, every once in a while gaining back his own comic book, but for now he has to be in that third-tier of super-hero. Not in the movies, and not able to sustain his own comic book. He wasn't even included in the LEGO Marvel super-hero game... and they even included something stupid like Squirrel Girl. You only think I'm joking. She was even an Avenger in the comics.
In my opinion, Sub-Mariner needs to be recreated... given a whole new reason to hate someone or something. And maybe they should bring back the Original Human Torch and Toro, too. I have a plan... actually, I have a really good plan to deconstruct Batman for a year...
Marvel/Timely really seems to enjoy dehumanizing the Japanese within its comics... but with the unhuman-looking Sub-Mariner, the Japanese don't look as evil...