Seems to be triggered when you turn in the heart of a twisted stoneservant to Alaurin. Cons DB to lvl 70 & is indiff til you engage. Max hit on our tank was about 1700, max hit on caster was about 2.5k. Never got an AE either. Did it with a group of lvl 70's (war, shaman, chanter, cleric, monk, & pally) Died in about 3 mins. Pretty gimp. Hope this helps. =)
1 grouped this mob last nite....70 sk tanking, cleric, bst, wizzy, enc and myself (rogue). Never got hit with an AE and conned blue to me (i'm 66 btw). Granted he did have tons of hp and is most likely an under con, but we took him down with relative ease.