How does Valentine treat Ender, and how does Ender respond to the treatment? How does Peter treat Ender, and how this affects Ender?

Valentine— Ender’s older sister is the only person in the world who truly loves him. Shebprotects him from Peter, their sadistic older brother. Along with Peter, Valentine takes an active interest in the world’s political situation, and writing under the pseudonym Demosthenes begins to exert influence over the growing situation. Valentine also writes a letter to Ender at one point that helps him get control of himself. At the end of the book, Valentine convinces Ender to go with her to colonize the bugger worlds, and she works on a history of the world on the way there. Later she travels with Ender as he searches for a new world

for the buggers.

Peter— Ender’s older brother Peter is a cruel and evil child, gifted in manipulation. He has the same ruthlessness that his siblings contain but without any of their compassion. Valentine is able to protect Ender as best she can from Peter until Ender goes away. Peter then decides to take an active role in world affairs and convinces Valentine to help him. Under the pseudonym Locke he begins to gather power, working through the communication nets. After Ender’s victory Peter obtains total control of earth and becomes Hegemon, the ruler of the world. His ambition is sated and he actually makes for a good ruler, although he is as amoral is he ever was.

The very first game played in the book is "buggers and astronauts," a game that Peter makes Ender play, and it is a game that all kids play. However, in Ender's case the game is more than it seems, because Peter's hatred for him is real, and he inflicts physical pain upon Ender in the course of the game. This is one game that Ender never wins.

Ender tries to never hurt anyone, and even with Peter he gives compassion. He understands those who hate hin, and he has the aptitude to forgive them.