Uchiha Sasuke.

𝙎𝘼𝙎𝙐𝙆𝙀'𝙎 𝙇𝙄𝙁𝙀. 

Sasuke Uchiha (うちはサスケ, Uchiha Sasuke) is one of the last surviving members of Konohagakure's Uchiha clan. After his older brother, Itachi, slaughtered their clan, Sasuke made it his mission in life to avenge them by killing Itachi. He is added to Team 7 upon becoming a ninja and, through competition with his rival and best friend, Naruto Uzumaki, Sasuke starts developing his skills. Dissatisfied with his progress, he defects from Konoha so that he can acquire the strength needed to exact his revenge. His years of seeking vengeance and his actions that followed become increasingly demanding, irrational and isolates him from others, leading him to be branded as an international criminal. After learning the truth of his brother's sacrifice and later proving instrumental in ending the Fourth Shinobi World War and being happily redeemed by Naruto, Sasuke decides to return to Konoha and dedicates his life to help protect the village and its inhabitants becoming referred to as the "Supporting Kage" (支う影, Sasaukage).

𝘾𝙝𝙞𝙡𝙙𝙝𝙤𝙤𝙙. 

Sasuke was a happy child, eager to please and be worthy of his family name. This changed after his entire family was killed by Itachi, the person he most admired in the world. He became cold toward others, unmoved by and uninterested in what they do or think of him, choosing instead to keep to himself. He stopped using honorifics like "sensei" or "sama", something considered rude in the Japanese language. His only goal in life became to take revenge for his family's deaths and, by extension, acquire the power needed for that revenge, even if it meant acquiring an external power that wasn't his own.

The pursuit of power, difficult enough on its own, is something that Sasuke repeatedly struggles with. Whenever he meets new people, he makes an evaluation of their abilities: those he perceives to be weaker than himself he arrogantly disregards, giving them as little attention as possible so that they won't hold him back; those he perceives as stronger he fixates over and tries to surpass, especially when he believes he should be their equal. As a member of Team 7, he is repeatedly exposed to Kakashi Hatake's philosophy that there is strength in teamwork. For a time, Sasuke accepts this, experiencing it first-hand on several of Team 7's missions. He even starts becoming attached to his teammates and starts to forget the vengeance he craved. But when he meets Itachi again in Part I and is summarily defeated, Sasuke decides the team is making him weak and chooses to leave them and Konoha entirely, focusing solely on himself.

𝙎𝙋𝙀𝘾𝙄𝘼𝙇𝙄𝙏𝙄𝙀𝙎. 

Kishimoto conceived Sasuke as a rival of the series' title character Naruto Uzumaki. Despite Sasuke's dark character development later in the story, Kishimoto avoided portraying him as a villain; he found designing the character challenging and had difficulty creating a suitable look for him. Nonetheless, Kishimoto has grown to enjoy drawing him. In the manga's animated adaptations, Sasuke was voiced by Noriaki Sugiyama in Japanese and Yuri Lowenthal in English.