The Harbingers of Phlegethon
From Solium Infernum Wiki
Description
Men who molt like serpents will walk from the wishbone of the rivers Styx and Phlegethon. Blood and fire will fall from their armor. Touched ground will wither into charcoal, and breathed air will dust and thicken. At a city of disorder they will stand before the gates. Cut a man of the robes and they will follow; spare the man, and the gates will become earth. --Prophecy IV from “The Book of Infernal Assertions”