Unlock the characters below via the listed requirements.
Sasuke: In order to unlock Sasuke Uchiha in just about every mode, you need to beat story mode twice.
Itachi: In order to unlock Itachi Uchiha, you need to beat the Kakashi Gaiden, which you get by beating story mode once and completing all of the missions. You unlock him at the same time as Kisame.
Kisame: In order to unlock Kisame Hoshigaki, you need to beat the Kakashi Gaiden, which you get by beating story mode once and completing all of the missions. You unlock him at the same time you unlock Itachi.
To unlock the Kakashi Gaiden Story, beat all in-game missions.
To unlock all of the S Rank Missions in the game, complete the game once through in its entirety.
To unlock Temari, you need to beat story mode twice, as well as having beat all thirty-five missions and survival missions.