9. Dr J.S. Steinman (Bioshock)
You can't beat a good 'ol creepy doctor with something of a God complex, and that defines Bioshock's Dr. J.S. Steinman in a nutshell. Prior to everything going underwater, Steinman was a revered plastic surgeon, working for Rapture and generally doing good work making people look the best that they could. However, his over-zealousness became apparent once he realised that he could harness ADAM for the purposes of genetic enhancement, and like so many brilliant scientists, his ambition soon gave way to madness. Soon enough, he wasn't so much a noble surgeon as a torturer, having lost his mind, transforming people into grotesque "trophies" as he sought to perfect the human form. Though the whole mad scientist thing isn't too original, this take, with its back-story and strong character work, allows a truly sinister bent to cut through the entire game and totally enhance the atmosphere.