Once a raider, Jack cleaned up his act and began to marry his ruthless tendencies with a head for business. Some may say "Split Jack has an eye for business," (his only good one), for extortion, and he is currently leading a group of bandits as they attack, accrue, and he hopes extort Aqua Pura from anyone they meet. He's mildly psychotic, but you'd have to be paying attention to notice.
Protecting the Water Way: Once Split Jack's name and location has been revealed, the Lone Wanderer can choose to either kill Jack's whole band or replace him by challenging him to a death duel with pre-defined weapons. Additionally, if you have a high enough Speech, you can persuade him to stop hijacking water caravans. However, if this option is chosen, he will then order his men to kill whomever or whatever they please. This usually involves Grandma Sparkle first.