Karen was a street kid from a broken home. Before she was conceived, the man who would become her father henched for the criminal mastermind Doctor Demon. Exposure to radiation altered his genes, which were passed down to his daughter. Karen's powers manifested when she was a teen; at first, she used them for petty crimes, but that all changed when she fell afoul of the supercriminal known as the Brute, who almost killed her when her powers failed to affect him. Her life was narrowly saved by the timely intervention of Ms. Miracle. The experience gave Karen a change of heart; after a probationary period, she became a full-fledged member of the Crusaders.