Two of the main characters in Ender's Game are brothers, Peter and Andrew "Ender" Wiggin.  Peter is several years older than Ender.  They are both considered child geniuses.  Unfortunately they despise each other because Ender is a Third.  In the society in which they live the government only allows a couple to have two children unless given permission to have another child who is called a Third.

     In the beginning of the book the brothers are complete opposites.  Peter torments Ender and is cruel and ruthless.  Ender is pushed around, bullied and lonely because he doesn't have friends.  As the book progresses, Ender fears he is becoming more and more like Peter.  When Peter was six he had his monitor removed.  After school that day a group of kids surrounded him with the intention of beating him up since the monitor was  no  longer there to show what was happening.  Ender stood his ground and asked them, "You mean it takes this many of you to fight one Third?" The boys that had been holding him let go and then Ender was able to fight Stilson on a one to one basis.  Ender knocked him flat and then kicked the living daylights out of him so that no one would ever pick on him again.  As he enters battle school, Ender continues to become more like Peter even though he struggles to keep his humanity.