Who is Specialist 4 Robert L. Mountain from Bloods: An Oral History of the Vietnam War by Black Veterans and what is their importance?

Robert's mother is a guidance counselor at his home town high school. He loved music and played in the school band and was never any good at sports. Robert wants to play in the Army band but cannot handle boot camp and wants to come home. Vietnam turns Robert into a drinking, cursing, and smoking man. He begins to like shooting people just to see how they look dying. Robert feels nothing for the Vietnamese and does not have any problem killing them.