Exarch Onaala wants you to go to the ruins of Karabor and slay Alandien, Theras, Netharel and Varedis. Use the when Varedis uses Metamorphosis to weaken him. Return to Exarch Onaala with the Book of Fel Names after completing this task.
Completing quests for the Aldor will cause your Scryers reputation to decrease.
- Suggested Players 
All four demon hunters are scattered around. You will need to clear an area around each before starting the fight.
The three assistants can be easy handled by a group. Varedis is a little trickier due to the fact that he will need to be moved around so the tank does not stand in the fire. All four of them will metamorphose into a demon partway through the fight. You will only need to use the Book of Fel Names on Varedis. Using the book requires a long cast time (8-10 seconds). You must have Line of Sight to start using the book but you don't need it to finish.
Of course we must destroy this book, but not before we use it to destroy Varedis.
If we're to shut down this academy of Illidan imitators, we'll have to deal not just with Varedis but also the three night elf masters that assist him: Alandien, Theras and Netharel.
Gather a suitable force and return to the Ruins of Karabor. Follow Altruis's instructions for defeating Varedis. Hopefully his plan will work - otherwise... it'll have been a pleasure working with you.
Have you completed what I asked of you, <name>?
Excellent work, <name>! Your victory over Varedis will have a tremendous impact on our war against Illidan.