Urluk Cloud-killer was a warlock of the Stormreaver clan who followed Gul'dan into The Tomb of Sargeras. Not particularly talented, Urluk was growing wary of Gul'dan's thirst for power and betrayal of the Horde. He was frightened by the guardians of the tomb and so Gul'dan killed him. This act temporarily overpowered the rest of the group's fears and motivated them to search throughout the building. (ToD 301)