L'ghorek is the ancient that rests upon the shelf across from us. It is being controlled and its life energies slowly consumed by something immense beneath us.
There is a cave known as the Undershell down below L'ghorek. In that cave are three powerful ogre magi that are maintaining a ritual connecting the thing below with the ancient. You must kill these three to disconnect L'ghorek.
<race>-thing, I am in need of your assistance. Like your enslaved friends, I am a victim of the Lich King's ymirjar and their avarice. When I rose from below to investigate the noises coming from this cavern they captured and chained me.
Will you please help me? The foreman of these mines holds the key to my chains. Kill him!
When I sensed these... things... rising from below, I came to put them back down. I found the corpse of your friend and dragged him as far as I could before one of my fetlocks was broken. It is all that I can do to hold off these foul tendrils.
There is one that controls the tendrils and eyes. It calls itself Harbinger Aphotic -- I'm sure that you have heard it yelling from the south.
The harbinger stands out of range of my magic, but you could get to him. If you dare....