As we know some of the games in Facebook required you to invite some of your friends and earned some benefits and advantage. In this game having a friends or 'Buddies' has a lot of purpose , aside from adding more fun with the game.
1. You can steal exp from their Dojo. The more Buddies you have the more exp you can steal :).
2. You can rest in your Dojo and this will grant you 3 more fights in 6hours (a wish list will gives just 3 hours of resting)
3. You can hire them as your Assistant. Assistant occasionally will give you some exp and HP. If you lucky enough it can found a 'Treasure Chest' or an event edition.
4. You can fight with them in a 'challenge' at anytime especially if you have weak Buddies that you can take advantage :).