Sai

is a fictional character in the anime and manga series Naruto.

Background
The name "Sai" is given to him for the purposes of joining team 7, his actual name being unknown. Sai is the newest member of Kakashi Hatake's Team 7, recruited to join Naruto Uzumaki and Sakura Haruno, to replace Sasuke Uchiha, after his defection. Little is known about Sai; he was orphaned as a child and was brought into Root, an independent subdivision of the ANBU, which trained him to have no emotions so as to make it easier for him to accomplish missions. Sai at some point in time met an older member of Root who took a liking to Sai's drawing ability, and Sai came to think of him as a brother within the organization. Eventually, his brother died of illness, and Sai was once again alone in Root, thus was given the name "Sai".

Because he has no emotions and lack of personality caused Sai to meet with hardship upon joining Team 7, as he makes the mistake of insulting the other members in an attempt to seem sociable. He tries to seem more caring by smiling, though his teammates come to dislike it due to his obvious insincerity. After spending more time with his team Sai comes to appreciate bonds, particularly the bond that exists between Naruto Uzumaki and Sasuke Uchiha. Sai began to break out of his emotionless shell and started to value the concept of bonding with others. In doing so, Sai was able to start giving genuine smiles. Wanting to experience bonds for himself, Sai sets out to make as many bonds as he can. Sai has since tried to increase the number of people he bonds with by giving others pet names, though his habit of naming people after the way he sees them ("fat," "ugly," "hag") found little success. More recently, he has started to call people the opposite of how he sees them, earning him more of a liking from others.

Sai is a talented artist, and claims to have drawn thousands of pictures. Despite the magnitude of things he has drawn, he has never given one of his works a name, his lack of emotion making it impossible for him to give something a title. Sai's drawing ability is also the source of his jutsu; by drawing things with a brush on his scroll he is able to bring his creations to life, giving them an increased size and the ability to move. His Super Beasts Imitation Picture (超獣偽画, Chōjū Giga?) allows him to create birds that he can use for flight and lion-like creatures that he can use for attack. Likewise, by creating an Ink Clone (墨分身, Sumi Bunshin?) of himself, he can perform a reconnaissance of an area without actually endangering himself. Sai can also transform words he writes on his scroll into small animals that seek out their target and revert back to words upon arriving, giving Sai an easy way to communicate.

Sasuke and Sai arc
Sai is assigned to join Team 7 by his superior Danzo, and first introduces himself to Naruto by attacking him. After later meeting Sakura and temporary Team 7 leader Yamato, the group sets out to meet a spy of Sasori who has infiltrated Orochimaru's ranks. Soon after leaving Konoha, Sai begins to bad-mouth Sasuke Uchiha, earning him a punch from Sakura. Sai's standing with the team doesn't improve as their trip continues, as he often insults Naruto's manhood by questioning whether or not he has a penis.

Upon reaching the designated meeting place, Yamato goes ahead disguised as Sasori so that he can meet the spy. When the spy, Kabuto Yakushi, arrives with Orochimaru to kill Sasori, Sai, Naruto, and Sakura are called in for help. Soon after, Naruto and Orochimaru do battle, signaling the start of Sai's real mission. After leaving Yamato's side and deciding not to to save Sakura from falling off of a cliff, Sai watches Naruto and Orochimaru's fight from the cover of the neighboring trees. When Orochimaru eventually repels Naruto, Sai approaches him with a proposition from Danzo. Orochimaru accepts, and Sai accompanies him and Kabuto back to their hideout.

Along the way, Kabuto creates a Sai lookalike and leaves it behind to throw off anyone who may be following them. Once arriving at Orochimaru's hideout, Sai is introduced to Sasuke, who has been training under Orochimaru for the past two and a half years. Sasuke seems indifferent to him, expressing discontent towards Orochimaru instead. When Sai mentions that he might get along better with Sasuke than he did with Naruto, Sasuke fixes him with a stare, startling Sai due to the amount of fear it gave to his emotionless self.

After his meeting with Sasuke, Sai is lead to his own room by Kabuto, who locks Sai in when he leaves. Soon after arriving in the room, Team 7, having put extra precautions into following Sai, arrives and confronts Sai about his defection to Orochimaru. Because he has been caught, Sai divulges the information about his true mission: to ally with Orochimaru on Danzo's behalf so that the two may join forces in destroying Konoha. Disgusted by the ramifications of this plan, Team 7 takes Sai from Orochimaru's lair and restrains him. With Sai out of the way, Team 7 prepares to go looking for Sasuke, hoping to bring him back to Konoha. Sai, however, doubts their success, stating that Sasuke no longer cares about them. Naruto, in response, states that he used to hate Sasuke, but over time he has formed a bond with Sasuke through their shared experiences, and as such he will do whatever it takes to bring Sasuke home. Naruto's dedication to retrieving Sasuke strikes a chord with Sai, who is left without words as a result.

Just as Team 7 is about to leave Sai, Kabuto arrives and releases him, hoping that the two will be able to defeat Naruto, Sakura, and Yamato easier as a team. Before any fighting can begin, however, Sai, moved by Naruto's words and hoping to understand the concept of "bonds" better, helps Yamato immobilize Kabuto. After extracting some information from Kabuto, Naruto and Sai break away from the rest of Team 7 to find Sasuke. While they rest, Sai remarks how Naruto reminds him of his older brother, bringing an actual smile to his face as a result of his brother's memory.

Sai's happiness is short-lived, as Orochimaru soon arrives in an attempt to see where Sai's loyalties really lie. With Naruto's encouragement, Sai leaves the scene with the assignment to find Sasuke ringing in his ears. As Sai searches the numerous rooms of Orochimaru's lair, Naruto is rejoined by Sakura and Yamato, forcing Orochimaru to retreat. As Yamato goes through the belongings Sai left behind, he finds a bingo book that has Sasuke listed as a target, indicating that Sai's actual mission has, from the very start, been to kill Sasuke.

As Team 7 splits up again to catch Sai and stop him from accomplishing his mission, Sai finally finds Sasuke asleep in his room. Sasuke, however, is quick to notice Sai's presence and asks what he wants. Sai responds by saying that he is going to bring Sasuke back to Naruto instead of carrying out his mission, willing to fight to protect the bond that Naruto would give his life to defend. Angered that Sai woke him up for a discussion about bonds, Sasuke attacks Sai, destroying the room and causing a large crater to be left in its place. Team 7, attracted to the scene of the attack, confronts Sai about his actual motives. Upon learning of what Sai was trying to do, Sai is welcomed back into the ranks of Team 7, and the group joins together in an attempt to defeat Sasuke.

As the group surrounds and attacks Sasuke, Sai's attack is the only one that manages to be effective. After Sai is congratulated by Sasuke for this feat, the latter uses his One Thousand Birds Current to throw the group back. Uninterested in having a drawn out fight, Sasuke prepares to finish the group with a single attack, though before he can do so Orochimaru and a freed Kabuto arrive to stop him, and the three disappear. Team 7, having failed their mission, return to Konoha.

Team 10 arc
As Team 7 recuperates, Sai uses his spare time to read up on relationship skills and gaining people's trust at the Konoha library. As one could expect from someone who learned to communicate with others via a book, Sai initially has problems putting what he read into practice, but Naruto tells him not to worry about being formal. During Team 7's dinner with the members of Team 10, Sai puts what he's learned into practice, though finds little success.

Sai later comes to Team 10's aid in their fight against Akatsuki members Hidan and Kakuzu. Because Shikamaru Nara is separated from the rest of the group, Sai and Sakura are sent as backup for him, though upon arrival they find that Shikamaru has already defeated his opponent. Sai returns with everyone else to Konoha, having not taken part in the battle.

Current arc
After returning home, Naruto, Sai, and Sakura go eat ramen. Naruto has trouble eating his food because his right hand was broken, Sai ends up interrupting a tender moment between Naruto and Sakura by stuffing Naruto's face with noodles because he read in a textbook that he should help his friends. While usually true, Naruto goes off on him for ruining the moment.