Grr..
I've already beat this game, but level 6 is pain in my buttocks. I can never hit the moving guy, my shots always end up going just above his head...
AlexTwinkle: I beat Cerberus by putting Gelyan at the very back of the party, and put the rest in front of him, forming a shield. Gelyan's 'Soul Pact' ability comes in quite handy, especially if you have a health upgrade, along with the high priestess to heal him.