Sai is an ANBU-level shinobi of Konohagakure and a member of Team Kakashi, having replaced Sasuke Uchiha, in Naruto. Orphaned as a child and recruited into Root, a secret branch of the ANBU, he was raised to have no personality, personal connections, or a name. Despite this, Sai became friends with a older boy named Shin, who was supposed to fight to the death via Root regulations. However, Shin died of an unnamed illness before the fight and Sai's Root training suppressed most of the memories.
When he first meets Team Kakashi, Sai lacks an understanding of social experience and personal initiative. He has great trouble in understanding how bonds between people can motivate others and is often confused be decision made by Naruto. Over time, Sai comes to appreciate bonds, particularly the bond that exists between Naruto Uzumaki and Sasuke Uchiha. This causes him to break out of his emotionless shell and he starts to remember his past.
