"He was thorough. He didn't just beat him, he beat him deep…" (Card 9). This shows that violence is wrong, even in self-defense. Ender believed he was becoming like his brother, Peter. He felt guilty. He believed violence was wrong. Ender did not like being as violent as he was becoming because he knew his brother was violent, he felt bad, and he knew it was a bad idea.
Ender knew that being so violent was making him like his violent older brother. He realized it many times throughout the book. "I'm doing it again, thought ender. I'm hurting people just to save myself. Why don't they leave me alone, so I don't have to hurt them" (Card 115). Ender thought he was 'becoming' Peter.
Ender had felt guilty about killing Stilson and Bonzo. He knew there were better ways to keep them from getting hurt. He knew that fighting them in the first place was wrong. He knew that there probably would be some kind of penalty. Ender was afraid of becoming like Peter. Ender had a guilty conscience.
Violence was against Ender's morals. Ender had often been bullied by Peter. He had seen violence in how the buggers were killed. He had killed two people unintentionally. He did not like the violence of the Battle Room. Ender believed that violence in any situation was wrong.
Ender did not like being violent since he knew he was being like Peter, he felt guilty for causing pain, and he had good moral values. Ender knew he was acting like his brother. He was feeling guilty. His conscience was telling him that he'd done something wrong. "Ender isn't a killer. He just wins - thoroughly" (Card 226). Ender knew violence was wrong, even when defending himself.