Who is Peter Wiggin from Shadow of the Giant and what is their importance?

Peter Wiggin is the ambitious, older brother of the famed hero Ender Wiggin. Peter did not make the cut for Battle School, which bothers him into his adult life, but now capitalizes on the fact that he is Ender's older brother as he unites the world under one government in the name of world peace as Hegemon. His methods are ambitious and ruthless but they work as he establishes the Free People of Earth, which requires all the people to ratify a contract relinquishing their autonomous freedoms as individual nations.