Best way to kill it is to not bring lots of people with you, "best" would be something like:
NIN THF BRD + Healer
Let the NIN tank and do damage, the THF ONLY uses SA & TA, BRD uses eva & haste song, keep up Elegy & baraera on the tank.
When he does the 3x AoE don't recast shadows unless Ni is up and just cure the NIN through it.
Besides that, gl and hf :)