First, find a fight that have a preon nurse in the enemies. Destroy all the others but DO NOT DESTROY the preon nurse. After it's done, instead of attacking you, he'll surrender and will cast "all life gain 25" on you. It's not a lot but it's useful when your life tank is empty. (NOTE: this trick works once in a battle. If u don't destroy it after his healing turn, he'll run away!)