This quest is not available in game.
Retrieve the Arcane Shard from Morphaz and return to Archmage Xylem.
There is a green drake deep in the sunken temple of Atal'Hakkar by the name of Morphaz.
Years ago, he overwhelmed me in a bold ambush and consumed my apprentice whole. While the loss of an apprentice is not unknown to me, this particular one carried an arcane shard of unsurpassed size and quality.
You must gather powerful allies and delve into the temple. Destroy Morphaz and recover the arcane shard from his ageless stomach.