This is the chapterwhere Ender gets a new team of rookies and misfits, and begins training them in tactics that include using their bodies as shields and weapons in the Battle Room.  More importantly, in this chapter Ender finally realizes that the “enemy” is Graff and the other military types running the camp.  Ender has been there three years, so if he was 8 (his brother Peter was 10, and his sister Valentine is between them) when he joined the program, Ender is now about 11.  Why Card does not state his age directly is not clear, but what is clear is that Ender enters the program as a pre-pubescent child, and reaches a young maturity by the time he battle the Buggers.  That is what makes this novel a Bildungsroman, a “growing up” story, like Salinger’s Catcher in the Rye and Golding’s Lord of the Flies.