When Khan began to unite the numerous gangs, he faced the problem of ideological unity among the half-crazed raiders. He had to find something that everyone would fear more than death. Instead of inventing something new, he turned to witches, sorcerers and other psychics already existing in the mass consciousness (and newly appeared in wastelands after the disaster).
He personally met with several of them and made an offer to everyone, which was impossible to refuse. Thus began to form a caste, responsible for ideological work with the masses. In a few years the number of Firestarters increased. Now each unit has at least one mobile tent, or a mortar, or a cauldron, or at least a crystal ball, through which they contact the beyond. And control raiders.
And to ensure security in the material world, each such car has an elite guard unit.
It is by no means a fact that Firestarters possess some kind of supernatural abilities. But they do have a talent for presentation! Former actors, musicians, and just crooks with conspicuous looks and sufficient courage form the backbone of this faction.