You have to score 3 stars per battle set.
Here are the requirements for achieving 3 stars per set:
Keep everyone alive. Equip Anti-Poison and Absorb Fire on everyone for added advantage.
Kill the dog using Poison rings, as this is the only way to take him down. You should achieve Perfects with your hits or the skill master will do more damage. Equip Persistence on Kaim for added advantage. He can be tough, so save first since you might have to try again.
Hit the Moneys with fire spells or Fire-based melee attacks (or All-Flare spells). They only do coin tosses if they're hit with fire based spells or attacks, and they do not do it all the time too. You have to acquire 10 favorable coin tosses within 10 turns, and you need to defeat them within that period too. Patience and luck is required.
Cast Gamble on the Silver Kelolon.