They're clearly outmatched 1v1, but if they manage to pull themselves together and fight in a more coordinated manner this shouldn't be so bad. The enemy's mana coating him like that kind of reminds me of Protoss plasma shields from StarCraft, maybe they can break through it with enough attacks, it probably functions like an initial HP bar (out of several) if this were a game.
Maybe I'm an idiot because I only realized just now that their party does not have a healer in it (unless the white mage IS the healer a la Final Fantasy), unlike the hero party who has the saint as the healer (at least it seems like she is, but I've only ever seen her fail to heal somebody...).