Bruce Wayne became Batman after his parents were gunned down in front of him but that all changes in the crossover event Flashpoint. The Reverse-Flash travels back in time and alters history so that Bruce was killed instead of his parents. Now Thomas Wayne dons the cowl in Flashpoint: Batman – Knight of Vengeance.
Thomas Wayne may be older but the Dark Knight has nothing on him. He has no compunction about killing but while super villains like Poison Ivy are pushing up daisies, the Joker runs wild. After escaping from Arkham Asylum, yet again, Joker kidnaps Judge Harvey Dent’s children to “play house.” You don’t have to be the World’s Greatest Detective to deduce the reason that Batman is pulling his punches is because the Joker is his wife, Martha Wayne!