Sasuke Uchiha is a main character from Naruto. He was once a member of Team Kakashi (Team 7), but left
and betrayed his friends sometime later. Naruto swore he'd get Sasuke back. Sasuke had became an enemy of Naruto since then.
(SPOILER ALERT: Years later, after many battles, Sasuke helped in a war where he redeemed himself in the process. He then left the Leaf Village on a journey of redemption.)