Maybe about 3-4x the hp of Cinderwing.
1 hit KO's everyone, nothing can save you if he gets his attack off.
Armor and magic armor is through the roof.
pdef- is needed for warriors to do any sufficient damage.
Elemental magic does next to nothing, but their status effects still apply to him just like any other mob.
You get 3 rounds of free hits before he starts to attack you. Make it count.
After round 3, He begins his attack phase, consisting of Gae Bolg( which is pretty much all he uses) which is an 1 hit ko AOE spell. (do not rely on silence(spell) to keep him from attacking.)
(I find that Meteor or Meteora works best.)
(stun locking, as cheap as it might be, may be the only way to kill him without you getting rekt.)