Defeat Dr Lugae in the two battles. First one is easy and is more of a joke to make you laugh then a battle. The second can be a bit annoying. Dr Lugae has a reverse ability that switch the polarity of damage/healing. every time he use it switch polarity, so pay attention or use libra once to scan him so you can see his current status. Attack with weapon/magic when he doesn't have reverse and unless you have better things to do use healing on him when he has reverse power active.
Keep in mind that he cast the same power on your party members which will cause healing spells to damage and raise to fail. so keep an eye on your own status before applying heals as well.