John Leber served in the United States Marine Corps (USMC), finding a fondness in marksmanship, before being cycled into the United Nations Peacekeeping Corps for a short period of time, being stationed in Chernarus to assist with the recovery of the area following the civil war. After the infection, John was to be exfiltrated - although that didn't occur due to lack of unit cohesion and the general amount of chaos building up. Without the majority of outside communication available, John set out to maintain himself and survive. After long periods of isolation, John continued to push through and survive on scavenged items - although became slightly loopy, losing parts of himself that once defined the man. Leber typically prefers to be isolated, the relatively long periods of time being alone molded into himself. Despite this, the core values that were forged into John remained quite strongly. He's performed some negative actions, murder, thievery, you name it. There's always an excuse for everything, something to keep him going. John's only goal is to survive in this hell of a world. Leber still, above everything else, sees something positive in the simplicity of some things - but wouldn't hesitate for a second to turn things back to the way they once were.