Dispater

The Voice of Iron
One of the first three Arch-Devils alongside Asmodeus and Mephistopheles is the cunning Dispater, lord of the second layer of Hell named after him, the iron city Dis.

More so than any devil other than Asmodeus, Dispater is in the business of obtaining the souls of mortals. He is the easiest of devils to strike a deal with. If it's wealth, strength, command or revenge, Dispater can see it so for the price of your soul. If a warlock has obtained their powers from the infernal devils, then it is likely Dispater's patronage that fuels them.

Dispater's layer is unique for hosting a diverse myriad of beings in his Iron City. Planar travelers from all over the great wheel come to deal with devils, night hags, rakshasas and other fiends. Any deal that is sealed in the walls of Dis lends power to Dispater's arsenal, there is very little he doesn't know or can't find out.