When you first start the game, wait for the "PCCW Japan" logo to come up. When it does press and hold L1, then rotate the right analog stick five or more times. You'll hear a confirmation sound when the code is entered correctly. This will unlock the fifth character Iria in story mode. It will also unlock all the characters in duel mode, as well as an all new mode called "Full Attack". This mode plays pretty much like story mode, but when you continue you have the option of changing characters. You also get a sixth bonus character in "Full Attack" mode, Alicia the fallen angel. Once this code is entered you can save your game and everything will remain unlocked on your game file.