"Lucky" Jim Harding is a former rebel leader currently residing in the Mojave. During the King's Rebellion, he was stationed in the Sewers, where he delivered messages and supplies. At some point he left the Sewers with Pacer and a number of other rebels and headed to Jacobstown. This group survived for 13 years, until tensions arose between Pacer and Marcus. Eventually, Pacer's group mutinied, resulting in the deaths of Marcus, Pacer, and many of the rebels. Jim sent word to the survivors of the fight to regroup at a shack on Lake Mead before heading to the outskirts of Searchlight.
Lucky Jim can be found where the Lonesome Drifter's camp is in vanilla, although he is marked as a generic "Survivor".