Highwayman
When people walled themselves off from the lawlessness that prevailed after the collapse of civilization it left a variable frontier in the vast open spaces on the other side of those Walls. A new profession emerged, the Highwayman. A set of hired guns that acted as guardians protecting people who had no choice but to travel from one community to another.
In the early days the highwaymen destroyed as many lives as they saved giving them a less then desirable reputation. Some people saw them as saviors while others viewed them no better than the lawlessness beyond the Walls. As the years went on, however, civilization slowly returned to the world creating less demand for the skills of Highwaymen. In later years those with such skills used them to eke out a meager existence as couriers and guns for hire.