I beat him!!!!!!!!!!!!!!!!!!!!!!!!!
My strategy was like this:
Marine summoned Jeanne,Benoit used iron hand to stun him(and then I needed to revive him),Karine just atack(I equiped her with the best weapon I had for her,Hirodo used that spell that paralyze and then atack)
Round 2:Marine double slap until it's over and then atack,Benoit halve the defense,the rest the same
Round 3:Marine the same,Benoit halves the atack ,the rest the same
Round 3:All the same,but at this time it wasn't stunned anymore so I used Iron hand again
All the other rounds:Just atack like an animal and it should go down,trough it will take some time.
This is just how I did it,the others may have another strategy trough
That was one big fight
