In short, I want people to think that I'm bad *** or even an evil psychopath who could kill somebody without feeling anything so that they don't see me as a weakling and try to prey on me or hurt me. Under the tough exterior though, I'm nothing more than an outcast. A mere shadow in darkness that lurks at the edge of society.

I suspect you will find that few are fooled, and at worst they will just think you are just a bit odd and be uncomfortable around you. So your strategy is, as you have observed, self-defeating. Good luck in your new and IMHO rather better strategy.