13. David Cain

David Cain was one of Batmans original trainers and is, in DC continuity, one of the worlds premier assassins. He taught Bruce Wayne some of the skills that he would take in to his career as the Batman, but also inadvertently taught him some important lessons about the real value of human life. However, despite Cain initially being the master, in the years that Batman has been in operation, hes managed to completely surpass Cain in terms of ability. Nolans franchise sort of skipped over Batmans training and posed that he basically picked up most of his skills from Ras al Ghul (under the guise of Henri Ducard), however Waynes road to Batman - which in comic book lore was fifteen years long - would make for some superb Kill Bill vol. 2 style flashbacks in any upcoming Dark Knight movie. And Im even fairly convinced this whole concept would also make for an epic TV show  imagine Smallville without the diabetes inducing sweetness.