The Seal of the Earth is held by three runestones, held in the Pillars of Diamond, Opal, and Amethyst in Lethlor Ravine. Using the Sign of the Earth, you will be able to remove the runestones and unlock the Seal of the Earth.
Be wary though, <name>, the black drakes Blacklash and Hematus are not to be trifled with. See them dead and return their bindings to me.
To reach the ravine, travel to the far eastern part of the Badlands. Be careful though, for the ravine is home to countless drakes.
The black dragonflight continues to ally with the renegade Blackrock orcs, and both must be brought into line, or removed. With Blacklash and Hematus dead, we can turn our attentions westwards, towards Blackrock Spire.