Here are a few contenders:
* The Human Torch (1939): This character, originally from Timely Comics (which later became Marvel), predates even the name "Marvel" itself. However, his early appearances were more in the realm of science fiction adventure than superheroics.
* Captain America (1941): Another Timely Comics creation, Captain America is often cited as the first true superhero from Marvel. He embodies classic superhero tropes like patriotism and fighting for justice.
* Namor the Sub-Mariner (1939): While technically appearing before Captain America, Namor initially served as a villain. However, he later evolved into an anti-hero and even a member of the Avengers.
So, while there is no definitive answer, Captain America is often considered the first true superhero from Marvel Comics due to his iconic status and consistent embodiment of superhero characteristics.