Code to Unlock All Characters
At the main menu, simultaneously hold "R1" and "R2" and press "Square," "Triangle," "Square," "Triangle." Then release "R1" and "R2," hold "L1" and "L2," press "Right," "Up," "Right," "Up," then release "L1" and "L2," and press "L3" and "R3." A chiming sound will play if the code was successful. This will automatically unlock all characters except for Hanabi and the Fourth Hokage.
Story Mode Unlockables
Most of the extra characters can be unlocked by playing through the Story Mode. The unlockable characters acquired by completing all of the missions are Haku, Zabuza, Orochimaru, Sandaime, Gaara, Kankuro, Temari, Kisame, Itachi, Kabuto, Shizune and Tsunade.
RPG Mode Unlockables
Several extra characters are unlocked by completing challenges in RPG Mode. To unlock Anko, Asuma, and Kurenai, you must respectively challenge and defeat them as you play through RPG Mode. To unlock ANBU Kakashi and Green Beast Naruto, you must complete RPG Mode.
Post-Completion RPG Mode Unlockables
Several of the RPG Mode unlockables may only be acquired on the second playthrough. After completing the mode for the first time, go back and enter the Academy. Complete Moegi and Udon's riddle challenge to unlock Konohamaru. Once Konohamaru has been unlocked, go to the restaurant and take Ebisu's challenge to unlock the First and Second Hokages.
Unlock Hanabi Hyuga
After completing RPG Mode once, go back and play the dating game until you meet Hanabi. Date her and she will be unlocked.
Unlock the Fourth Hokage
After you unlock all of the other extra characters, you will receive the Fourth Hokage.
Multiplayer Unlockable Characters
Several characters have alternate forms that can only be accessed in multiplayer mode. Hold down " Select " while you choose the character to access these forms. The characters who have alternate forms are Choji, Gaara, Jirobo, Kidomaru, Kimimaro, Naruto, Rock Lee, Sakon, Sasuke and Tayuya.