Who is Caliph Alai from Shadow of the Giant and what is their importance?

Alai was a member of Ender's Jeesh, and since his return to earth has been Caliph, which is his title as leader of the Muslim world. The Muslim armies have invaded and conquered China because they put Alai in charge. As Caliph, he doesn't only have charge of the military but he is also the leader of their government and religion.