I'm a huge fan of the Saw franchise. Jigsaw is one of my most favorite movie villains. My idea will have little canon with it, only the fact that the killer targets those that have no appreciation for their own lives. I'll be writing as a female, the only requirement for the opposing character is that they are attractive and human. The entire 'purpose' behind the character being tested is that they showed a unique ability to save their own life, no matter what. Instead of loathing the person that tested them...they became a disciple.
If you think this might be for you, feel free to pm, if not...Thanks for reading.