Do a certain number of matches to unlock characters.

Character	How to unlock
Asuma	Complete 500 matches.
Chouji	Complete 150 matches.
Hinata	Complete 260 matches.
Kabuto	Complete 320 matches.
Kiba	Complete 230 matches.
Orochimaru	Complete 420 matches.
PTS Naruto	Complete 460 matches.
PTS Sasuke	Complete 490 matches.
Sai	Complete 120 matches.
Sasori	Complete 90 matches.
Sasuke	Complete Story Mode or do 70 matches.
Shino	Complete 290 matches.
Tsunade	Complete 400 matches.
Yamato	Complete 150 matches.