when cassie was introduced, she was the daughter of an archaeologist, dr. helena sandsmark, a friend of wonder woman's. to help wonder woman during an adventure, she borrowed magical artifacts which bestowed upon cassie superpowers, with which she fought crime as wonder girl. later, zeus, king of the greek gods, grants her real powers. later revelations showed that cassie was in fact a demigoddess and the natural daughter of zeus and dr. helena.