Slade Wilson was 16 years old when he first enlisted in the United States Army, having lied about his age. After serving a stint in Korea, he was later assigned to Camp Washington where he had been promoted to the rank of major. In the early 1960s, he met Captain Adeline Kane, who was tasked with training young soldiers in new fighting techniques in anticipation of brewing troubles taking place in Vietnam. Kane was amazed at how skilled Slade was and how quickly he adapted to modern conventions of warfare. She immediately fell in love with him, and realized that he was without a doubt the most able-bodied combatant that she had ever encountered. She offered to privately train Slade in guerrilla warfare. In less than a year, Slade mastered every fighting form presented to him and was soon promoted to the rank of lieutenant colonel. Six months later, Adeline and he were married and she became pregnant with their first child. The war in Vietnam began to escalate and Slade was shipped overseas. In the war, his unit massacred a village, an event which sickened him. He was also rescued by SAS member Wintergreen, to whom he would later return the favor.