How does Ender change throughout the book, Ender's Game? In what parts of the book is this shown?

Ender begins the story as a naive, trusting six year old,
but not as the typical six year old of today. He is extremely gifted in battle and
strategies beyond his years. As the events unfold, Ender becomes a lonely outcast and
understands that he is being manipulated by the adults and the military. He learns to
cope with the loneliness by withdrawing from people. He learns from situations, both
good and bad, and puts that knowledge to work manipulating others. He becomes cynical
yet masterful. His love of his sister never dies, and the manipulative military uses her
to steer Ender in the direction they feel is best. Ender knows this but continues to
love his sister while steering the military in the direction he wants them to go. Once
the war is over, he withdraws from the world and travels in space doing only what he
wants with his equally burned out sister as his companion.