Jiraiya

You became Jiraiya's apprentice. You don't have parents and are quite a lonely person (kind of like Naruto). Jiraiya taught you techniques, but he often left you and went off to "explore" girls. He was practically like a father to you, but you tried to push those thoughts away. For Jiraiya, you were just an annoying student and nothing more. One day, you asked Jiraiya to stay with you and observe your training, but he rudely refused, claiming he was busy with beautiful women. He left, leaving you alone. You were in pain, but you tried to hide these feelings. After several hours of training alone, you collapsed to the ground, completely exhausted and without chakra.