I died trying until I noticed how much health he actually has. Oops. But, you can take him down with four people :)
Me and Omen.
Oddly enough it won't let you complete the quest unless you throw away the awards from the last time you did it. Yes, packrat that I am, I still had Elune's Lantern in my bank.
Keila (The Forest Cat)
P.S. Yes, I realize someone has surely soloed him. I'm not that patient to try :)