13. David Cain
David Cain was one of Batmans original trainers and is, in DC continuity, one of the worlds 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, hes managed to completely surpass Cain in terms of ability. Nolans franchise sort of skipped over Batmans training and posed that he basically picked up most of his skills from Ras al Ghul (under the guise of Henri Ducard), however Waynes 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 Im even fairly convinced this whole concept would also make for an epic TV show imagine Smallville without the diabetes inducing sweetness.