Gender in speculative fiction
The first known female superhero is writer-artist Fletcher Hanks's minor character Fantomah, an ageless, ancient Egyptian woman in the modern day who could transform into a skull-faced creature with superpowers to fight evil; she debuted in 1940 in Fiction Houses "Jungle Comics".
Black Widow (Marvel Comics)
Claire Voyant is the first costumed, superpowered female protagonist in comic books. Created by writer George Kapitan and artist Harry Sahle, she first appeared in "Mystic Comics" #4 (Aug. 1940). She kills evildoers to deliver their souls to Satan, her master. The character is unrelated to the later Marvel Comics superheroines who took on the codename.