Dennis Joseph O'Neil (May 3, 1939 – June 11, 2020) was an American comic book writer and editor, principally for Marvel Comics and DC Comics from the 1960s through the 1990s, and Group Editor for the Batman family of titles until his retirement. His best-known works include Green Lantern/Green Arrow and Batman with Neal Adams. It was during this run that O'Neil co-created the Batman villains Ra's al Ghul and... see more