An officer from International Fleet (or I.F., Earth's government and army to fight against the Buggers) named Colonel Graff comes under the pretense of interrogating Ender for the incident with Stilson the previous day. Ender explains that he defended himself, and then decided to keep kicking because, "Knocking him down won the first fight. I wanted to win all the next ones, too. So they'd leave me alone." Chapter 3, pg 19 The rationale is enough for Colonel Graff to invite Ender to join Battle School, the elite training facility where future commanders of the army were trained as youth. Ender's parents had signed papers for him to go to Battle School at birth, because his status as a Third child is illegal in this future, except with government waiver. As Graff explains, "[Peter] was the best we'd seen in a long time. We asked your parents to choose a daughter next - they would have anyway - hoping that Valentine would be Peter, but milder. She was too mild. And so we requisitioned you." Chapter 3, pg 24
Ender is ultimately given the choice, however, because Graff wanted a volunteer, not a conscript. The prospects looked dim - ten years with zero contact between him and his family, intense military and academic training, and the possibility of future glory. Ender's greatest motivation to leave is fear of his own life at Peter's hands. Ender's only reason to say no is Valentine. Graff is not only aware of these factors, but confirms them. His parents will miss him but they will get over it, Peter will not miss Ender, and only Valentine will think of him consistently in the years that follow. Ender, impressed with Graff's forthrightness, feels more comfortable. Ender decides to go, reluctantly: " 'It was what I was born for, isn't it? If I don't go, why am I alive?' 'Not good enough,' Graff said. 'I don't want to go,' said Ender, 'but I will.'" Chapter 3, pg 26
