Sasuke Uchiha is a fictional character in the Naruto manga and anime series created by Masashi Kishimoto. He was created as a rival and foil to the series' titular character, Naruto Uzumaki, with his design causing difficulties for Kishimoto during drawing the manga scenes, although he has grown to enjoy drawing Sasuke.
During Part I, Sasuke was considered the best Genin of the Rookie Nine and could have been the strongest. To this end, Sasuke's only desire as a shinobi was to get stronger, and he saw everything from his teammates, to the other villagers as simply being in the way. In fact, during their bell test with Kakashi, Sasuke's reason for not working with Naruto and Sakura was because he thought they were respectively weak and annoying, and they would get in his way. However when he was proven wrong by Sakura's knowledge, and Naruto's desire to also become stronger he began to value his teammates and even began to risk his life to save them if he needed to, valuing their lives more than his desire to kill Itachi.
During the Chunin Exams, Orochimaru noticed how Sasuke's desire for revenge seemed to have lessened, and branded him with the Cursed Seal of Heaven to give him a taste of the power he could have if he keeps to his previous path of vengeance. Even when Kakashi sealed the Cursed Seal, Sasuke began to draw more and more power from it in hope to get stronger. However even with the Cursed Seal, Sasuke began to envy Naruto, whom he saw as being much weaker than himself, because in their brief encounter, Itachi says that Naruto has a "special power" and that he came back to Konoha to find him, not Sasuke. Slowly Sasuke saw Naruto surpass him, and in the end, Sasuke decides to leave Konoha to join Orochimaru to make himself stronger. Sasuke remembers that Itachi told him that in order to be as strong as him, Sasuke had to gain the Mangekyo Sharingan and to do that, he had to kill his best friend. When given the chance to kill Naruto and get the Mangekyo Sharingan, Sasuke simply punched him in the chest, sparing him as to not give Itachi the satisfaction of seeing him follow his path.
In Part II, Sasuke showed he had stayed true to his original personality. When first meeting Sai, he did not care the slightest and was interested more in Orochimaru's training him. When Sai states that he might be able to get along better with Sasuke than he did with Naruto, Sasuke freezes him with a stare, catching Sai in a genjutsu which involves a large amount of killing intent. Sai is amazed that even an emotionless person such as himself was affected by Sasuke's gaze, showing the power of his Sharingan. When Sai comments on how Naruto and Sakura have been searching for him, Sasuke once again shows his uncaring nature.
It would appear that during his time with Orochimaru, he has come to the conclusion that if he ever wishes to stand a chance against Itachi, he needs to push away all of his past bonds with his friends and make revenge a priority, above even his own life. Because of this, he shows that he no longer cares about Konoha or anyone from his former village. In spite of this, he scolds Naruto about risking the lives of an entire squad to save one man, and comments that it could damage his chances of becoming Hokage. He also states that, unlike their last encounter at the waterfall, he has no more reservations about killing Naruto, and attempts to do so. He's also aware of the fact he is intended to be the container for Orochimaru's soul, showing that he doesn't care what happens to himself as long as it results in Itachi's death. This attitude seems to have changed, however, as Sasuke comes to the conclusion that Orochimaru only wants him as a container and attempts to kill him. During his attack, he emphasized to Orochimaru the superiority of the Uchiha clan, demonstrating that he still holds his clan in the highest regard, and that Orochimaru taking his body would be an insult to the clan's reputation.
Unlike Kabuto or any of Orochimaru's subordinates, who address Orochimaru as "Orochimaru-sama" (which shows that they highly respect him), Sasuke simply refers to him as Orochimaru. Sasuke also never called Kakashi "Kakashi-sensei" (teacher) like the others did, something the Japanese would consider as very insulting or rude. Despite his association with the Sound Village, Sasuke does not wear a Sound headband, unlike most other subordinates of Orochimaru. He still wears the fan symbol of the Uchiha clan on his back, albeit much smaller and higher up by his shirt collar. Despite this lack of allegiances to those close to him, Sasuke seems to be unable to bring himself to needlessly harm those that have nothing to do with his quest for vengeance against Itachi, and makes it a point to prevent their deaths when possible.However, this attitude appears to have changed after he learns the truth about Itachi's death and swears revenge against Konoha. Not only does he resolve to destroy all of Konoha(despite the majority of its villagers having no involvement in the Uchiha massacre), but he also seems to be willing to take the lives of anyone who stands in the way of his revenge.
Ironically despite his hatred towards Itachi, Sasuke's demeanor has become much like his older brother's. Becoming so single-minded and relentless on whatever goal he sets, Sasuke seems to have developed tremendous self-control, rarely showing much emotion, even in the heat of battle. Only when the situation involves Itachi would Sasuke show visible irritation.
Upon learning the truth about Itachi, Sasuke is filled with sorrow and, for the first time since the night of the Uchiha massacre, weeps for his brother's sufferings. After he has mourned Itachi's death, he resolves to avenge Itachi and tells Team Hawk that they would 'crush Konoha'. He later states that he only intends to kill the three elders of Konoha who were responsible for it. However, it is eventually revealed that Sasuke's true intention, which he hid from his team, is to kill everyone in the village, not just the three elders, thus going against Itachi's wishes. Sasuke holds all of Konoha guilty for the death of the Uchiha clan, taking for granted the peace they live in and their wrongful worship of the Senju clan, because of this he believes that the entire village must pay for it with death.
Despite this, during their fight with Kirābī, Sasuke saw Team Hawk in a similar light as Team 7 (prior to his defection), and realized he was never alone.
Sasuke has black hair with a blue tint that lengthens as the story goes with onyx eyes and has lighter skin than his brother Itachi. Like many other members of his clan, his hair hangs over both sides of his face to roughly his cheeks. In his curse seal form, he has grey skin with wings on his back that resemble giant webbed hands. He also has hair similar to Madara Uchiha except in a greyish-blue color.
At the beginning of Part I, Sasuke's clothing made up a blue, short-sleeved shirt with a raised collar and the Uchiha crest on the back and white shorts. An interesting thing is that during Part I the Uchiha symbol on his back gets smaller each time he changes his outfit. In the last stage of the Chunin exams, he wore a black, one pieced version of this outfit but eventually went back to his original clothes.
In Part II, Sasuke has grown noticeably taller (almost eye height with Itachi) and slightly more muscular. wears a white long sleeved shirt that's open at the torso with a smaller version of the Uchiha crest on his collar. He wears black pants with a blue cloth hanging from his half way up his stomach to his knees. He also wears a purple rope belt (Japanese name: Shimenawa) tied in a bow fashion found on many Sound ninja, only the bow is in a different style and is tied in the front instead of the back. He also will at points remove his shirt and hang it from his belt around his waist to give his wings in Curse Seal Level 2 room to move (also without transforming).
After battling Deidara, his upper body fatigue was changed to a sleeveless black colored shirt, his armguards were also removed and he started using bandages on his wrists and a bandage on his forehead. He also wore a cloak with this.
After he encountered and battled Itachi, he reverted to a white shirt with a raised collar that's unzipped half way down his chest, similar to the one he used at the start of Part II, but with shorter sleeves. He also wears blue wrist warmers. He currently wears an Akatsuki cloak along with this. An another noticeable trait is that since joining the Akatsuki, Sasuke now lets his hair hang over his eyes.