Gatefather: A Novel of the Mithermages

Danny North is the first Gate Mage to be born on Earth in nearly 2000 years, or at least the first to survive to claim his power. Families of Westil in exile on Earth have had a treaty that required the death of any suspected Gate Mage. The wars between the Families had been terrible, until at last they realized it was their own survival in question.

But a Gate Mage, one who could build a Great Gate back to Westil, would give his own Family a terrible advantage over all the others, and reignite the wars. So they all had to die. And if the Families didn't kill them, the Gate Thief would-that mysterious Mage who destroyed every Great Gate, and the Gate Mage, before it could be opened between Earth and Westil.