Who is Han Tzu from Shadow of the Giant and what is their importance?

Han Tzu whose nickname is "Hot Soup," is a Battle school graduate and former member of Ender's Jeesh. Back on earth now, he stands up to the Chinese authorities by pointing out the error in their battle strategies, but they don't listen to his advice. As a result, when things go wrong just as he predicted, the military supports him, and he becomes the leader of the Chinese nation. Yet this pits him against another former Battle School graduate and member of Ender's Jeesh named Alai, who is now the Caliph of the Muslim worlds.