The battle is simple, since the Emperor is only slightly more powerful than his cohorts, whom the party has been fighting regularly up to that point. The party should defeat the extra foes first (since the Emperor cannot be attacked directly while they are alive), and attack the Wood Golem with Fire-element abilities. The Emperor will attempt to strengthen himself, along with his guardians with Blink 8 and Haste 6, but the difference will be negligible. His level 10 Thunder spell can be a nuisance, but otherwise the Emperor is not much of a threat.