Z.A.G.

Before the war they were known as Zheng Corp. They specialized in biogenetics focused on replicating the human body, and were known for loaning artificial organs to impoverished people in need and retrieving them once they defaulted on their payment. By the time the bombs fell, the world was so ravaged by pandemic that Zheng Corp had locations in major cities all over the world.
When the bombs fell, the remnants of Zheng Corp went underground. Their CEO was an eccentric of the time, and built vault level facilities beneath several of their locations so that they could continue their work after the bombs fell; however, this CEO became obsessed with cheating death, creating synthetic bodies for himself and transferring his consciousness into them over and over. 400 years later, he is a master artificer and has separated from the company. He now wishes to be called Endless and the Cult of the Endless One was founded by those who left Zheng Corp to follow the former CEO, becoming the first of his now numerous flock.
After his departure, the company's power-hungry board of directors took over and they became the Zheng Ascension Group (Z.A.G.). Now they run the same organ loan sharking racket that they did before the war, but this time it's even more accessible and needed by the general public. Their repo men and women are some of the most fearsome warriors in the wastes; ask anyone, you don't want a zag on your tail