A former Confederate States Army Captain and slave owner from Meridian, Mississippi. After returning home from the war, Cullen discovered that his wife and son had been slaughtered by Union soldiers.

Bohannon sought revenge and journeyed out west, tracking and hunting down each member responsible for his family’s murder which eventually brought him to the mobile encampment known as "Hell On Wheels".

Over time, Cullen eventually renounced his vengeance and became a 'railroad man'. 