Lumber Jack was a member of the guerrilla force fighting against the Los Santos regime. A failed operation separated him from his companions and forced him into hiding in the jungle. He did such a good job at staying out of sight that everyone forgot all about him. He thus carried on with his revolution, keeping to himself and all the while unaware that the government had collapsed. It was Pandagran who eventually tracked him down and brought him back to Clint City where he's now eager to vent some of that frustration in the ring!