A particularly ugly combo I've found is MC Fire Mage, Celeste, Josef, and Haniya. Stack Celeste's bonuses to d12s using Something Angelic each fight, and use either the MC's Burning Fist or Haniya's Taking Spear to generate enough dice to regularly trigger Celeste's Angelic Prediction. Between that and Josef's chances for additional free d12 Damage dice, the numbers get pretty absurd.