Alright so there's 2 ways, the cheesy way and the normal way. The cheesy way involves using all your ethers and spamming overloads, the non cheesy way involves running a fairly specific setup. The thing you need to know is you have a limited amount of time to kill it, or at least to stagger it 4times. He's hard to stagger, so you cannot stagger him with only one role, unless using the cheesy way. You'll also want one setup that has Artemis Arrow(garb you get as a reward for killing one of the giant plants, quest in the forest village at night in the wildlands). Try to farm/craft a Heavy Slash 3, Anubis mobs in the palace drop it fairly often especially if you use the accessory that removes gold drops but increase item drops, go to the room with the crystal shit and just run in circles avoiding the shitty mobs. The other thing you probably want is the 75% magic resist accessory on your saboteur role, along with paladin armor(10%magic resist and guard 3) and the arm accessory +10%magic, lets you block all his spells for 0dmg other than his special moves. You want Imperil, Deshell and Deprotect on that guy. You can also run Defaith and Debrave on another schema to survive his big attacks, but having 3 or so phoenix downs is enough, you just die and rez up.
Then you need 2 good stagger spells on your other setups, aerora or thundera preferably but I used blizzara on my artemis schema cause I didn't have a high lvl aerora/thundera but had a lvl 4 blizara. Other than that, ATB shields on everyone(or at least artemis+caster), ATB accessory if you have some, you probably want the omega reaver sword on the artemis character(since it's 900/900 it makes your spells do good dmg too but mostly it's the best weapon until the last dungeon), caius weapon on the caster(stagger sooner, very strong), I used L'automne for the garb since it has thunderra/aerora 3 maxed. Also want one of the arm accessory to be the one that makes you immune to Fog.
Then you basically debuff(need double casts for shit to stick), spam all your ATB on the caster, then the artemis, just spamming ra spells, and switching to the debuffer to block spells with(so you take no damage). It doesn't take too long to stagger. Just keep staggering, use some of your EP if you want(it refills both your ATB bars so make sure to use it when you're empty in both), once it's staggered 4times it takes a ton of damage, at that point swap to Artemis and just spam that. Drink a bravery pot+enwhatever pot for more damage but not necessary tbh. EP to get ATB bar back, or just cast spells for a bit, once he's full staggered he's pretty much dead since he does shit for dmg. The part you want to try to speed up with EP is between stagger 2 and stagger 4 or so, cause he has hellblast or whatever and that kills you even if you block it, you need to perfect block it and even then it's retarded dmg unless he's defaith/debrave.
If you have a bunch of ethers though, you can run the same setup but stagger him with only one character spamming overloads, don't need to switch and don't need to block as much, so the fight is a lot shorter. Use the accessory that reduces EP costs if you do it this way, unless you're playing easy(since overload is 1EP in easy mode).
