Skull of the Lich Lord. Annals of the Nameless Dwarf, #5

The Nameless Dwarf is sentenced to death by the survivors of Arx Gravis. It is a fate he willingly accepts. The assassin Ilesa has abandoned him, and so it falls to the rogue Nils and the wizard Silas to stage a rescue. But with the Lich Lord's grimoire obsessing him more and more, Silas may no longer be in control of his destiny. Sick and close to death, he is haunted by visions of an ebon staff in a forest of tar.
As a chilling doom closes in on the companions, the last of the dwarves are threatened with extinction at the hands of ravenous beasts that live only to feed. And in the background, orchestrating it all, lurks an implacable horror Nameless had thought destroyed:A skull with crimson eyes that feast on living souls. All that remains of Otto Blightey, the Lich Lord of Verusia.