Jex was a Human male Mantellian Separatist during the Ord Mantell Civil War against the Galactic Republic, which was backing the Mantellian Government. He was stationed in the Separatist Base on Mannett Point when a promising Republic Commando infiltrated the base. He was encountered by the Commando along with his wounded Separatist fellows, but the Commando let them go under the condition that they'd fight no more.