Nazgrel's Fervor is an area buff that affects all of Hellfire Peninsula and Hellfire Citadel. It is obtained by turning in Magtheridon's Head to Nazgrel in Thrallmar. The head drops after defeating Magtheridon in his lair in Hellfire Citadel. It grants a 10% Thrallmar reputation gain and persists even in death.

The Alliance counterpart is Trollbane's Command.