He was hitting my characters for 8 hits 300 damage each round and they were only doing like 50 damage with swords (with Haste). Cure3 was only 100 healed so you do the math there. I'm not doing class change so I don't have Bolt3 or Invis2. I never had problems with him before because I always used a balanced setup so I didn't bother with any detailed strategy. Mistake.

EDIT: Yeah, Invis1 + Defender = No contest. Need to remember that for the later battles. 3 crystal down!