Why would Itachi be the main reason Sasuke exists? We know he's Sasuke's main motivation in being a cheap punk who puts his friends in danger while chasing more power from a known evil bastard .. but Sasuke is a central character, Itachi is not. In the realm of literature, Itachi is what is known as a peripheral character. He serves his purpose as a secondary antagonist. Sasuke shares the 'star-of-the-show' status with Naruto.