If you have a fighter/mage (dual or multi) he can whoop their asses very quickly.
Stoneskin, Prot. from Fire, saves vs spells. well below 0 (Potion of Invulnerabilty), PFMW
Now have some bad dualwilding combos and improve haste your char and he eats them for breakfast.
Solaufein with FOA and Angurvadal beat the whole bunch of them alone. The rest of the party were just chatting meanwhile.