What part does Assef play in Amir's life in The Kite Runner?Assefs' character and actions.
The evil Assef is the son of parents who are friends of Baba. While Assef's father is a Pashtun, like Baba, his mother is a native German and follower of Adolf Hitler. The blonde-haired Assef worships Hitler, and he patterns his own life after the German dictator. Assef first appears as the local bully who threatens Amir and Hassan; it is Hassan who stands up to the much older and larger boy, threatening to shoot out his eye with his slingshot--an event that foreshadows Sohrab's own final confrontation with Assef. Assef sodomizes Hassan in retaliation, and Assef later shows up at Amir's birthday party, where Hassan is forced to serve the boy who raped him. Assef becomes a daily reminder to Amir about his betrayal of Hassan: Amir can never escape the guilt he feels for failing to come to Hassan's aid when he is attacked by Assef. Assef makes a surprising return into Amir's life when he turns out to be the Taliban leader--now residing in Baba's old home--who has imprisoned Sohrab as a sexual play toy. Amir, who has never thrown a punch in anger, is forced to fight Assef for the possession of Sohrab. Assef beats Amir to within an inch of his life, but Sohrab comes to his rescue--just as his father, Hassan, had done in the past--saving Amir with a single draw from his ever-present slingshot. Amir's battle with Assef proves to be the single most important part of his own self-redemption, and his bloodied body serves as atonement for his past sins.
My body was broken--just how badly I wouldn't find out until later--but I felt healed. Healed at last. (Chapter 22)