Ender:

In the battle room, after he was moved up to salamander army, he grouped his launchies together and showed them maneuvers and strategies that he learned from Petra.

Ender is a quiet, and isolated boy, he is a third that means he is "unwanted" even tho he was wanted by his mother and father. The government only allows 2 children to each family to be covered in full cost. Schools paid for but now that they have ender, his mother and fathe must pay for him to go to school unless he gets into battle school...

Ender is tormented by his older brother peter. Peter was in the program but stats showed he was too violent to handle battle school. His sister valentine was also in the program but stats showed she was to caring. So it's up to ender to prove he is the one.