For a moment, as Ender looked around at the laughing, jeering faces, he imagined their bodies covered with hair, their teeth pointed for tearing. Am I the only human being in this place? Are all the others animals, waiting only to devour? (7.103)
Every once in a while, Ender will say something that sounds like he’s a budding serial killer, like this. (That is, once you imagine that other people aren’t even human, it’s kind of easier to kill them; and in this case, Ender might think he’s killing them out of self-defense since they’re the dangerous animals.) We could also look at this quote and note how isolated Ender is – after all, if he’s the only human in the place, not only does he not have friends, but he couldn’t really make friends who were his equals even if he tried.