Longest battle in the entire fight, but not that hard. You need three things to win: Glide, Cure, and Sora's Trinity Limit. Basically, you unleash Trinity on a random boss character. While you're performing your hacky slashy combo, you're invincible, so you just damage and forget about the foes. As soon as it finishes, Glide away. You might take one or two hits there, but you can get out totally unscathed. Next, just head to one of the walls and Glide Glide Glide around in a big circle all around the room. You should find that the bosses leave you alone, either staying in the center or trying to follow, but being too slow. So Glide around the room until your MP is back. If you need healing, trigger Cure, otherwise, unleash Trinity again. Either way, your MP is gone and it's time to Glide some more. Takes a long time, but it's effective.