The Iron Giant will most likely start the battle off with Crush which will inflict instant death on one character. To start off, have either Rosa or Porom revive the fallen character, and start casting multiple Blinks (or Mirage, if using Edge) to avoid physical hits altogether; as well as Protects to raise defense, for when Blink wears off. Have the other team members use Spider Silks to slow Iron Giant down. Make sure not to use magic on the Iron Giant as it may possibly counter with Meteor on the party, which can cripple an unprepared team. Use your best physical fighters to slowly whittle the Iron Giant's health down. Have a character equipped with the Ogrekiller to deal massive damage.