What level were you when you beat here? i'm lvl20-23 and i dont do alot of damage still trying to find her weakness
I faced her around these levels, I don't remember much, but what I suggest is that you avoid the yellow fey attacks because the Nighmare is immune.
I don't know what spells you have or the rank level of your witches.
But I suggest you leave aside the healing spells and only use the combo heals.
