Rumble in Outland:

Black Temple

Long ago on Draenor, the Temple of Karabor was the center of Draenei worship. But the devout priests who prayed there are long dead, slaughtered by marauding, demonically corrupted Orcs. In the massacre's aftermath the warlocks of the Shadow Council seized the structure and bestowed upon it a new name: the Black Temple. When Illidan the Betrayer fled to Draenor, he ousted the Pit Lord, Magtheridon, and claimed his throne as the lord of the blasted world. Despite the bitter retribution of his enemies, Illidan tightened his grip on Outland from within the profaned sanctum up until his death.