Many details about the CoM battle system remain unreleased but below are a few points that give structure to the system:
The system will use a method of cards, by which you can choose an attack or method of attack. These attacks include the traditional spells, physical attacks and summons. It is assumed that you may obtain different and more powerful cards as the story progresses. By these cards the CoM is straying away from both KH and KH2, and it should be a very unique system. Also new features have been added such as the ability to play character cards and assume the body of a plot character such as Cloud. Although this is not confirmed, it seems likely. More updates on the battle system will come when they are availiable.