Kill High Cultist Zangus and return High Cultist Zangus's Head to Captain Gort at Agmar's Hammer in the Dragonblight.
I witnessed his treachery with my own eyes! The traitor led an Anub'ar assault on this stronghold, taking out some of my best soldiers.
<Gort shakes his head.>
He'd been working with the Scourge the whole time and we didn't have a clue! How many more like Zangus are there? We'll find 'em all and when we do...
<Gort makes a cutting motion across his neck.>
First on the list is Zangus. Our scouts report that he is hiding in The Pit of Narjun, west of here. Find him, kill him, bring me his head.