SUB-ZERO. The code name used by U.S. Army Lieutenant Mark Habershaw, born in Smithfield, Rhode Island. Habershaw was an instructor at the Army Northern Warfare Training Center in Fort Greely, Alaska and consultant to that base's Cold Regions Test Center. His colleagues believed his impressive cold weather endurance records were due solely to Sub-Zero's meanness. He later trained troops in Europe's Operation Chill, and eventually served with the G.I. Joe team before it was shut down in 1994. Today, like many Joes, he is a reserve member of the team. Sub-Zero was assigned to exterior security for the Joe's arctic prison, The Coffin, during the conflict known as World War III.