Ender's older, scary brother
Peter gives off bad vibes. Even other people are frightened of what he will do.
"His brother. Aren't you afraid of what his brother will do to him?" (Card 9).
Peter shows no emotion. He never felt anything besides anger.
"Ender looked at Peter only to detect anger or boredom, the dangerous moods that almost always led to pain" (Card 10).
Peter was very jealous. He was mad that Ender kept his monitor longer than Peter.
"I lost mine before I was five. He almost made it, little bastard, little bugger" (Card 10).
Peter is relentless. He never stopped even when Ender was in a lot of pain.
"Just press and press until you're dead. And I could say that I didn't know it would hurt you, that we were just playing, and they'd believe me, and everything would be fine" (Card 12).