The Orc King is accompanied by two Orcs. If you're strong enough, you can take them out first, but if you want the fight to be easier, then focus on the main boss. You can use the Hand Grenades found in the cavern to cause a lot of damage and since they start out close together, you can damage them all at once! If things get ugly, then use Sue to heal while Justin attacks. Don't waste you SP on the normal Orcs. The fight can become even easier by using accurate critical attacks to cancel the enemy's moves.