Defense, Stamina, Attack and Balance. Balance is, as the name suggests, the one that doesn't have any particular advantage or disadvantage. Attack types are weak against Defense types since their specialty is quickly bursting the opponent. They're strong against Stamina types that outlast any other type but don't have a strong guard. With Defense and Stamina it often comes down to an endurance battle, since neither type is aggressive... That's why Stamina has the upper hand.

In theory, anyway. Technique makes all the difference. Final Guard is a defense move, but as you saw, it can be used aggressively as well.