Have you looked at the walkthrough?
If you don't really want spoilers (even though you're pretty much done with the storyline outside of the LG):

Watch his buffs/debuffs: hover over every one. If Tsunami appears, block with all your pets. (Always have enough mana to block, don't mend unless you have at least 40 mana. No need for finishing blows here, I made it through without.) If Planar Shift appears, take out the minions as quickly as you can, as he regenerates health and is invulnerable to damage until you do. If you're over level 60 and have the right gear on your pets (don't be having strength gear on int pets) it should be fairly easy.

Here are his stats, for reference:


Really, watching the buffs only becomes more important in the Lost Grove and Ethernia Arena, if you choose to go into that.

Ah, thank you!