Obito Uchiha

He's your close friend at Minato's team 7. Only you and Kakashi are alive and so is Obito. He lost hope in this shinobi world because Rin sacrificed herself in the hands of Kakashi, What's worse is Rin never knew how much Obito loved her, Rin was more focused on Kakashi as she loved him. One day in a mission you, Kakashi and Kakashi's team 7 goes to a mission to confront Obito (Minato is reanimated to join)