You find magic keys at various places in the world to unlock more tiers in Backyard, which is an underground fighting cage contest. For each tier there are several fights you can take part in, each is a battle with a certain configuration of enemies. If you win the fight, you a 2 stars clear and a reward. If you fulfil a secret condition in each fight, you'll get 3 stars clear and a bonus reward. The more stars you acculmilate as you complete the fights and the bonus conditions (you don't get more stars for redoing fights

) you can also get prizes. Some fights have special conditions, like "only two characters" or "no item" or "no attack" and so on. Pretty fun, and the battle theme for Backyard is brand new.
