Keep the Secret Safe

Objectives
Librarian Serrah in the Transitus Shield needs you to kill Arcane Serpents near the Nexus and collect 5 Nexus Mana Essences from them.
 * Nexus Mana Essence (5)

Description
Our existence here depends entirely upon staying hidden. Should the shield fail, even for a moment, Malygos' minions would have us.

One of my responsibilities is to rejuvenate the warmages' mana levels so their focus doesn't falter. With our supply lines lost, I've been forced to improvise.

I could use your help,.

Very near the Nexus, Arcane Serpents feast on the abundant magical energies. Once defeated, they will yield a mana essence that I can make use of.

Progress
Do you have the mana essences I asked for?

Completion
Your service to Dalaran will not go unnoticed,.

I hope you find this payment sufficient.

Rewards
You will also gain:
 * +250 reputation with Kirin Tor
 * 20,100 XP
 * 20,100 XP