The adventurers have delved into the Abyss to strike at the Demon Lord of Undeath, Orcus. On the layer of Thanatos, the Blood Lord has many outposts from which he spreads his corruption. One of his primary lieutenants is Doresain, the Ghoul King. If the PCs kill Doresain in his lair, they will strike a real blow against the foul demon lord. Pgs. 174-179