Themes Present In Kite Runner

Tragedy is very present in the book. At the beginning, the relationships were tragic. The sadness of the relationship between Amir and Hassan was almost unbearable. The way Amir treated Hassan was tragic. Another trgic thing is how everyone in Amir's life is now dead or dying: Hassan and his family, Baba, Ali, Rahim Khan. To me, it is the most tragic thing that all Amir can do about all of it is find Sohrab. Sure, that will mean something, but it cannot fill the holes left by all of those deaths.
Forgiveness is also a relevant theme. At the beginning, Hassan always forgives Amir for treating him like crap. It is a heartbreaking forgiveness, one where you just want to slap Hassan for doing it. Baba always forgives Hassan, even for "stealing" what he did not steal. The amount of forgiveness done by everyone around Hassan is great. Later, Amir goes back to Afghanistan to forgive his sins.
That is another theme present: sin. The amount of sins in the book is massive. First you have Amir, who is horrible to Hassan and who watches things happen to him that he could have stopped. It is a terrible sin to treat someone that loyal and kind that horribly. Even Baba, who always talks about how the only sin is theft, robs Amir of knowing that he has a brother. Assef raping Hassan sinned. Every character is this book has sinned in some way, even the most wholesome.