Speak with Zureetha Fargaze.
Zureetha has been sending novices like yourself to help cull the numbers of the creatures in the cave near where you fought the vile familiars.
I think it would be good for you to gain experience by assisting her. Be sure to tell her that you assisted with the imp problem, she'll probably have a reward for you.
You have done well, <name>.
Although the vile familiars were merely pets of the darker powers within the Burning Blade, your success against them foretells greater deeds ahead.
You will be able to choose one of these rewards:
Upon completion of this quest you will gain:
The entirety of this quest happens at Durotar