Speak with Aurel Goldleaf in Cenarion Hold.
[player], Aurel Goldleaf thinks she's found a way to summon and defeat a ruling member of the Abyssal Council! Such a task will be dangerous, but you have earned great respect amongst the Cenarion Circle. We know that if anyone can do it, you can.
May fortune go with you, [player]. Speak with Aurel when you are ready.