How will I ever defeat the star magician in treasure isle ?

First you must meet up w/ isaac and friends, then you go to treasure isle. In your party you should have your most powerful people and mia (make sure your party is well balanced. Have judgement, and meteor ready to use. If you have eclipse, use him instead of judgement. Unleash both of your summons right away. You should be able to kill both the gaurd ball and the refresh ball right away. Aways use mia's wish well or jenna's cool aura. Make sure to use everybodys djinn except for the healer. Your priorities should always be to kill the refresh balls and sometimes the guard balls. Ignore thunder balls and the anger balls. This is a water guy, so use lots of fire psyenergy or fire attacks on him. Be prepared to switch people in and out of the battle. The batle takes a while but you should be able to kill him in a half hour or less. NOTE: use attack djinn and use the djinn iron and such to block some of his attacks
Good Luck!