Vampireslayer by William King, published in 2001, is the sixth book of the Gotrek & Felix saga and the one where the series' long-running adventures acquire a lasting scar. In the aftermath of the war in the north chronicled in Beastslayer, the companions are drawn onto the trail of Adolphus Krieger, a charming, coldly ambitious vampire who has acquired an ancient artefact of terrible promise — a relic with the power to bend other creatures of the night to his will. If Krieger reaches his goal, the scattered aristocracy of undeath could be gathered under a single ruler, and the Old World given a new master.
The pursuit runs south into Sylvania, Warhammer's cursed heartland of the Vampire Counts, and King commits fully to the register the province demands: fog-drowned villages, terrified peasants, ghoul-haunted woods and the brooding ruin of Drakenhof castle. Along the way the story strikes its cruellest blow — Ulrika Magdova, the Kislevite noblewoman whose complicated romance with Felix had run through the previous books, falls into Krieger's hands, and what he makes of her cannot be undone. The saga had killed characters before; here it does something worse, and Felix's grief, guilt and helplessness give the novel an emotional weight the series rarely attempted.
Vampireslayer matters both as one of the strongest self-contained gothic adventures in the classic run and as a turning point for the wider saga: Ulrika's fate reshapes the remaining King novels and eventually spun off into her own vampire series penned by Nathan Long. For readers of the Slayer books it is essential rather than optional — the volume where following a doom-seeker stops being romantic and starts exacting its price from everyone standing nearby.