Proof of Demise: Ley-Guardian Eregos

Objectives
Archmage Lan'dalock in Dalaran wants you to return with the Ley Line Tuner.

This quest may only be completed on Heroic difficulty.
 * Ley Line Tuner

Description
The Nexus War rages on and we must do something to turn the tide! Are you willing to fly into the heart of the battle, ?

Ley-Guardian Eregos is the protector of the conduit through which Malygos is funneling the magical power of Azeroth's ley lines. If he can be slain it will be a great blow to the enemy.

Please bring me one of his ley line tuners so that we might study it.

Rewards
You will also receive:

Progress
Has the ley-guardian been dealt with, ?

I needn't remind you that Malygos is attempting to stop the use of all magic in the world, and that the blue dragonflight is slaying anyone that knows how to wield it who won't turn to their side?

Completion
Thank you,. The examination of that tuner should provide us with further insights into how Malygos is manipulating the ley lines.

If we can find a weakness in his approach, we might be able to exploit it and turn the tide.