How about military guys trained to kill people in seconds by crushing the other guys throats or ripping their balls off, those kind of things? I'm guessing if there's multiple opponents many will run away or think twice about fighting a guy that just killed a man on front of them. I'd choose him and stand back so I don't get done for murder haha.
You have to get w/in range first.
Bottom Line:
YOU CAN'T TRAIN A CHIN!
Most MMA fighers get real weak in the knees when they get their chins tapped.
http://mmameetsboxing.blogspot.com/