Quote 1
“These other armies, they aren't the enemy. It's the teachers, they're the enemy.” (8.126)
Ender’s worst enemies seem to be the childhood bullies he faces; but many of Ender’s friends appear to think the problem is the teachers and the other adults. (This quote is said by Dink, but a similar issue comes up with Petra earlier (7.189).) This sets up the idea that there might be a war between the generations going on here.
Quote 2
He held up a limp hand. "See the strings?" (13.105)
Here Ender is complaining to his sister (during his visit to Earth) about how he’s being manipulated by the adults in his life and has no real options. In other words, he feels like a puppet. Which is exactly what Peter called him in 2.64. Just a coincidence, right? Or maybe we’re meant to draw some comparison between the different manipulators in Ender’s life.
Quote 3
“In the moment when I truly understand my enemy, understand him well enough to defeat him, then in that very moment I also love him. I think it's impossible to really understand somebody, what they want, what they believe, and not love them the way they love themselves. And then, in that very moment when I love them –"
"You beat them." For a moment she was not afraid of his understanding.
"No, you don't understand. I destroy them. I make it impossible for them to ever hurt me again. I grind them and grind them until they don't exist." (13.127-129)
Ender may be a product of war, and he may be very good at it, but in some ways, he’s also a casualty. Think about it. If Ender loves the enemy, then destroying the enemy is always going to be a little painful. (Or very painful.) This is part of why Ender seems like a sad character in this book: the thing that he’s so great at (war) is painful. (Although the fact that we see Ender’s pain but not the pain of, say, Stilson, does strike us as a little odd. It’s important to remember that Ender isn’t the only casualty of his wars.)
Quote 4
"Maybe they gave up and they're planning to leave us alone." (13.253)
This is Ender’s (correct) guess about the buggers. This hints at Ender’s big wish in his wars: that people would just leave him alone. For instance, he fantasizes about Peter leaving him alone (1.16) and he cries out to Dink that he didn’t want to attack Bonzo and wished that people would just leave him alone (12.122). What’s curious here is that Ender’s personal enemies simply won’t do that, but the buggers really are leaving humans alone.
Quote 5
"They don't want to teach me everything," Ender said. "I wanted to learn what it was like to have a friend."
Alai nodded soberly. "Always my friend, always the best of my friends," he said. (7.55-56)
Going along with our last quote, we can see that Ender’s friendships are still complicated: Graff may be his friend (in some way), yet he can’t, you know, go out and see a movie with him. Meanwhile, Alai may be Ender’s friend for ever, but they’re still separated here. So even when Ender has friends, those friendships are complicated.
Quote 6
"It's good to know I have a friend here." But Ender wasn't sure Dink was his friend anymore. Neither was Dink. (11.81)
Ender has basically this same moment with Dink, with Alai (10.175), and with Petra (11.104). In all these cases, Ender’s old friendship is damaged by the game and Battle School. This reminds us of how Ender’s friendships are complicated – by which we mean that Ender feels like he doesn’t have any friends. That's a bummer, no matter how smart Ender is. Now, all these kids do show up at Command School and Ender seems happy to see them. But since he lost these friends once, couldn't he could lose them again?
Quote 7
"I'll carry you," said Ender, "I'll go from world to world until I find a time and a place where you can come awake in safety. And I'll tell your story to my people, so that perhaps in time they can forgive you, too. The way that you've forgiven me." (15.176)
After Ender’s relationship with Val (which is probably his most important), Ender’s fullest friendship might be his relationship with the species that he nearly drove to extinction. (Wow, and you thought his relationships with Dink and Petra were complex.) Although it only comes up in the last five pages, this relationship seems totally open. Ender and the bugger's relationship gives us an interesting model for friendship: the idea of one friend carrying the other. Is that a good model for friendship?
Quote 8
"I didn't want to kill them all. I didn't want to kill anybody! I'm not a killer!” (14.391)
What’s the difference between killing someone and being a killer? Ender admits to killing but keeps asserting that he’s “not a killer.” Basically, it seems like Ender is asserting that the difference between killing and being a killer is because he didn’t “want to kill them all.” Or is the distinction something else – is it a question of identity that Ender is refusing? (Like, what if you type – does that make you a typist? Well, maybe for the time that you’re typing it does, but what about after?) This is the major issue in the book, and it’s a question that we can’t answer.