Felicia Hardy was trained by her father as a great athlete. After his father capture as a cat burglar, she decided to follow his steps and use her abilities to become the Black Cat. First donning that name when she tried to free her father from prison, but she encountered Spider-Man. Since then, she felt a kinship with this lone hero, as she tried to change sides to be trused by the hero. Over the time, she gained special abilities of bad luck, which affected her relationship with Spider-Man and turnning her back to her old criminal career.
Anyways, Black Cat remained as an ally of the arachnid hero and helped him whenever he needed, trying to compensate their failed relationship. Currently a hero, Black Cat still manages to get something stolen from the good actions she makes.