Crime fiction
Over the history of the comic book genre, writers for major characters' series were required to produce material to strict regular publishing schedules that often ran for years. As such to fulfill this strenuous creative requirement, superhero stories have used a wide variety of story genres such as Fantasy, Science fiction, Mystery, Horror, Crime fiction etc. that put superhero characters in a vast variety and combinations of story settings and fiction tropes with their presence the major common element. As such, it has become an expected element to superhero fiction to be in nearly any story situation, including relatively down-to-Earth drama with their personal lives out of costume.