Sark's Lieutenant was an ENCOM program who operated as Sark's right-hand-man and lieutenant. He was a specialist in protocol and intelligence. His original user was Peter, Ed Dillinger's assistant. Sark called the Lieutenant "Null Unit" and "bit-brain," criticised him for showing initiative, and occasionally struck him in fits of bad temper. After Sark brought Dumont and his other captives to the MCP, the Lieutenant stayed behind to guard the path, and was derezzed by Tron, who had stowed away on the escape pod they'd arrived in.