Lathoric the Black is a level 46 named dwarf found deep within the Slag Pit in Searing Gorge. Lathoric is actually Dorius Stonetender, and has set up the player by faking his assassination. He betrayed his brother Curator Thorius by enslaving archaeologists sent to Searing Gorge from Ironforge, and the forcing them to work on the golem Obsidion. He had been corrupted by the Old Gods/Ragnaros, if that can explain his behavior.
Patch 2.3.0 (13-Nov-2007): Elite status removed and level changed from 52 to 46.