Sai
Sai (サイ, Sai) is a member of the disbanded ANBU faction: Root and one of the main supporting characters of the series. He is also a member of Team Kakashi replacing Sasuke Uchiha. Sai was orphaned as a child and recruited into Root, a secret branch of the ANBU. There he was raised and conditioned to have no personality, personal connections, or a name; "Sai" being given to him for the purposes of joining Team Kakashi.
Text from wikipedia
