Quest Objectives
Read the Tainted Tablet and speak to Nartok inside the Den in the Valley of Trials.
Provided: 
Tainted Tablet
Description
Ah, while you were gone a tablet came for you, ‹name›.
I usually avoid dealing with warlocks if I can help it, but I think you should read it when you have time. If I'm not mistaken, it came from your newly-appointed trainer, Nartok. He would have words with you when you're ready.
When you come back
Ah, you received my message. Excellent. We orcs have a long and turbulent history with the entities of the Nether, but now we forge our own path, in command of our destiny. You, too, can seize the power to shape the future for your people. Where our leaders falter, we are ready to press forward and claim our rightful place. You will be of eminence among the trolls.
When you hand it in
You have just glimpsed the power that can be yours. The feeble and foolish among us are afraid of the path that we tread, but with boldness and cunning we can decide our own fates.
Guard your powers closely. The fearful lash out against that which they do not understand.
Now you are one of us. If you need training in spells then return to me.