Use rescued characters in 1 Player Vs mode
After having defeated a character but before the next battle begins youll see the main character running accross a rainbow This is when you input the code Hold quotXquot and quotYquot and press Start A quotcharacter selectquot box will come up allowing you to swich characters before the next fight
Use RivalsBosses During Multiplayer
Go to the quotPlayer Selectquot Screen Hold the L and R buttons on both player 1 and 2s controllers for 3 seconds The bosses will appear and can be used in combat now