Some friends and I gave this NM a whirl, this weekend, just to test the waters, so to speak.
Our original set-up was SAM(tank), RNG, RNG, BLM, WHM, BRD (me).
The first two forms go down very easily.
The final form opened with Bad Breath and one-shot the SAM.
Second run we went as PLD, RNG, RNG, BLM, WHM, BRD.
Again, the first two forms are a joke. Burn them down fast, but try to have TP ready at the start of the third form.
With this set-up, we were able to learn some fun things about the final form:
It regens 2% per tick while not staggered. I don't believe it is possible to win without staggering. But if your DDs are top notch, only two back-to-back staggers are necessary to bring it down.
To stagger it, just weaponskill it as it is readying Bad Breath. RNGs are awesome for this. Bad Breath doesn't hit anyone behind it, so other DDs could work too.
Gravity works, and makes it easier for the PLD to kite/bait the NM into using Bad Breath when the RNGs are ready with TP.
Shadowbind also works if things go wrong.
Bring remedies, echo drops and poison potions.
We won every encounter but the first one. We ended the night as PLD, RNG, RNG, SAM, WHM, BRD.