pipe hitter
Some one or a group of people who are willing to go to the extreme in order to get things accomplished.  Most commonly refers to the special forces, but is not limited to that.  Can also serve as an extreme marksman(s). Someone who will accomplish any task no questions asked. It is rapidly evolving to encompass all those who live life to the extreme.
Black Water is full of pipe hitters, ready to go.
Pipe Hitters Union Creed: "Live extreme, always give one hundred percent and watch your brother's backs."