2. Jigsaw
Ageing, bed-bound, cancer-ridden serial killer John 'Jigsaw' Kramer came to respect life more after a failed suicide attempt. This experience led him to 'test' the survival instinct of people who he saw as flawed, by setting up elaborate (and torturous, nigh on impossible) 'games' for them to play in order to save their own life. At first, he'd do this himself, but soon came to need assistance and enlisted the help of the few who had survived his games to keep his legacy going. The problem here is that he is indeed ageing, bed-bound and cancer-ridden. This raises so many questions; How did he set the games up? How, if he's stuck in one place 99% of the time, hasn't he been found? How is he finding these victims? How is a man who came close to killing you able to manipulate you in to becoming his little lapdog apprentice? In a nutshell, Jigsaw shouldn't have been capable of doing what he did and should have been found and arrested quickly.