Mary Grayson was the wife of John Grayson, and the mother of Dick Grayson. She was a member of the Flying Graysons, a team that did acrobatic tricks without the safety of any net. When Bruce Wayne was attending Haly's circus, he witnessed the murder of John and Mary Grayson, when they fell to their death. Bruce Wayne eventually took in her son, Dick Grayson, as his ward and eventual partner. The murderer of John and Mary was Boss Zucco, a small time crime lord in Gotham City, who killed them when they wouldn't pay "protection" money.
In recent times, she and her husband have risen as Black Lanterns.