Not to mention that when Marvel started using the name "Captain Marvel"...the original character had been defunct for over a decade... and they only did it because another company was trying to use the the name recognition of Marvel with their own "Captain Marvel"
https://www.mentalfloss.com/article/...vel-characters
DC didn't even acquire the original "Captain Marvel" until 1972... 5 years after Marvel had created their own. DC tried to use the name on the covers...and got a cease and desist order for it. And then for the next 50 years or so...they tried to keep "Captain Marvel" as his official name...even though his comics were titled "Shazam". in 2012 they eventually just gave up and officially renamed the character as Shazam.Marvel was a buzzword again, and in 1966, a short-lived company called M.F. Enterprises tried to capitalize with a new character named Captain Marvel—generally considered one of the worst superheroes ever put to paper.
Marvel now needed to stop inferior comics from using its name on their covers, so it obtained the trademark for the Captain Marvel name and went about protecting it by introducing yet another character named Captain Marvel. This new alien version of the hero made his debut shortly after in 1967's Marvel Super-Heroes #12.
The character was born purely for legal reasons. According to comic book veteran Roy Thomas, Stan Lee only created a Captain Marvel at publisher Martin Goodman's insistence: "All I know is the basis of the character came from a resentment over the use of the ‘Captain Marvel’ name."