Beastchild - Dean Kootz

The Naoli came to Earth as conquerors, while the last men skulked through the ruins of their civilization. The two races, Human and Naoli, were the most powerful intelligence's in the galaxy -- and destined to be immediate and perpetual enemies! The adult Hulann met the boy Leo ... and each became a traitor to his race. For it was only through treason that the future of each race could be assured!