Twilight Highlands is found in northeastern Khaz Modan, east of Wetlands. It was once known as Northeron, and is location of the ancient dwarven fortress, Grim Batol, and also contains many Twilight's Hammer clan settlements. The cult, under the leadership of Cho'gall, is working with Deathwing and his black dragonflight.
The red dragonflight fights against them, though their numbers are small. The Wildhammer clan is fractured internally while facing the cult, and the Dragonmaw clan is ruled by a despot unwilling to join forces with the Horde. Both clans must be brought to their full strength in order for the cult's plans to be thwarted.