Pre-pull - YOU need to get "Goldfeather's Phylactery" on 3 people. I personally do my two priests and my enchanter.
To get these, disable cure curse, pull a floating dude (an aurumutation). Dispell him on whoever you want to get the item. This will give you a curse. This means you can freely move into the water/lava. It looks like a duck. Go click it, you will get a box in your inventory. Rinse repeat this until all 3 people have a box. The good news is, these do not poof if you die. Only if you camp (they are temporary). Cure their curse after you have the box.
Have proper belt immunities equipped:
Have pot cures on everyone. All the types. (Don't need all the types, but just do it for future)
Basics of the fight:
Interrupt, interrupt, interrupt. That's almost all that matters. You don't even need to do anything to make it happen. There is a new [x] Interrupt Mode option, that is turned on when you do a set up, and this will cast anything in your spell book to interrupt the mob. Literally, on everyone, the whole fight.
Okay okay fine, here's the actual mechanics, that you avoid by interrupt the mob.
He sends 1 person into the lava, and you need to pot cure it to get back. You will still get the crazy det, and there's a chance you will die when it sends you back to the group. If it happens, it happens. Interrupt better to avoid it.
He casts ruffle feathers, I think it's a mem wipe and extra damage. This should be EASILY interrupted and should never happen. If it does happen, he's likely to kill off a few people before you can get him back. Interrupt better.
He calls out for a HO, a mage (toon flag 1) will do it.
The boxes you harvested earlier, give you a arcane det. You need all 3 up in your group, or you can't damage him.
He puts a nox on some people. If it is not nox cured, it's basically a wipe. You NEED to have the immunity runes equipped for this to work.
Strat: Do the pre-pull stuff.
Campspot everyone, do a set up for.
You can either manually pull the mob (gross), or use one of the boxes you got (right click -> Use), and that will auto-pull the mob.
That's it!