Quest Objectives
Bring the Cracked Necrotic Crystal to Lieutenant Orrin outside the gates of Stormwind.
Provided: 
Cracked Necrotic Crystal
Description
On the corpse of the fallen abomination, you discover a cracked crystal, slowly pulsing with necrotic energy.
Rewards
You will be able to choose one of these rewards:
When you come back
Is there something you need?
When you hand it in
Hm, you took this from the corpse of one of the invading abominations?
We have received word about the necropolis base camps that are being summoned by the Scourge. I suspect they wanted to create one inside Stormwind. It is good that they were unseccessful.