The Wind of Change

Kolaz Umgal, known as the Black Fortress, must fall if the orcs are to eventually take Grimbeard Station. I would not be concerned but for the presence of a handful of Sigmarite mongrels sent from the nearby Temple of Sigmar to aid their stunted allies. One of these priests in particular, Jorn Schloss, has earned a reputation as one of Chaos' mightiest foes in Black Fire Pass. His death will shake the morale of the Sigmarites, as well as further the greenskin goal of taking Kolaz Umgal. Go to the greenskin camp at Drok's Fist, then make your way to Kolaz Umgal. Find this Schloss, kill him, and return here with his heart as proof of his demise. Should you fail in this task, it is best you take your own life. It will save me the trouble of killing you myself.

Travel to Drok's Fist in Black Fire Pass. Make your way to Kolaz Umgal, northeast of Drok's Fist. Locate Jorn Schloss, a Sigmarite Warrior-Priest who fights alongside the Dwarfs. Kill Schloss, then return to The Inevitable City and speak to Pherix.