Page 114 - Enders_Game_Full_Book

"Valentine, for Ender's sake, tell me what he does when he's being mean."
"He threatens to kill people a lot. He doesn't mean it. But when we were little, Ender and I were both afraid of him. He told us he'd kill us. Actually, he told us he'd kill Ender."
"We monitored some of that."
"It was because of the monitor."
"Is that all? Tell me more about Peter."
So she told him about the children in every school that Peter attended. He never hit them, but he tortured them just the same. Found what they were most ashamed of and told it to the person whose respect they most wanted. Found what they most feared and made sure they faced it often.
"Did he do this with Ender?"
Valentine shook her head.
"Are you sure? Didn't Ender have a weak place? A thing he feared most, or that he was ashamed of?"
"Ender never did anything to be ashamed of." And suddenly, deep in her own shame for having forgotten and betrayed Ender, she started to cry.
"Why are you crying?"
She shook her head. She couldn't explain what it was like to think of her little brother, who was so good, whom she had protected for so long, and then remember that now she was Peter's ally, Peter's helper, Peter's slave in a scheme that was completely out of her control. Ender never surrendered to Peter, but I have turned, I've become part of him, as Ender never was. "Ender never gave in," she said.
"To what?"
"To Peter. To being like Peter."
They walked in silence along the goal line. "How would Ender ever be like Peter?" Valentine shuddered, "I already told you."