2 Dark Knights + 1 Alchemist = Good party against Angra

Have the DK's cast Darkness every round, and make the Alchemist use their Mega-Potion Stash, or Mix Potions with Hi-Potions for the Mega-Potion effect (it would be wise to have 99 Potions and 99 Hi-Potions for this approach). Casting Protect, Shell and Regen might not be bad ideas, either.