The first DC representative on the list is David Cain, and with good reason. Cain is the man that trained Batman and fathered Batgirl - which is a pretty decent set of connections to have - and he is one of the most renowned bounty hunters in the DC universe. Given that he effectively taught Bruce Wayne everything that he knows - including many skills that the more principled Batman would never employ - it is fitting that he should be included here. Cain has teamed up with noteworthy DC characters such as Lady Shiva and Deathstroke in his paid missions, but it is his storylines with the Dark Knight and Batgirl that set him apart as one of DC's best assassins. He abusively and brutally trained his daughter to be a powerful fighter, and she was initially an assassin like her father prior to becoming Batman's aide. Employed to take out Batman, Cain instead elects to find out if Wayne is worthy of his daughter's loyalty and decides that he is. This sets up one of DC's most memorable storylines, as Cain and Batgirl finally come face-to-face, assassin-to-former-assassin. The daughter stands up to her father, proving herself to be less restrained than her mentor Batman, and is able to defeat her father in combat. Cain's training was clearly effective.
