>>154964I think the whole thing was that she was sterile or something? So she was useless to make Immortan Joe's desperately wanted unmutated son, unlike the captured women.
As a woman who couldn't bare a child, she was considered a man, and thus entered Joe's Warboy army, fought her way to the top and basically became one of his most trusted captains, or something.
She could fight off the peasants easily, and the other Warboys were presumably more sexually attracted to their cars than women.