Empire: Book 2, the Chronicles of the Invaders, Connolly John, Ridyard Jennifer

The Illyri have conquered and occupied the Earth. The Resistance are nothing more than an annoyance to the alien race of superior technology and military strength. When caught, young rebels are forced to join the Brigades, sent to the edges of the growing Illyri Empire.

Paul Kerr is one such soldier--torn from his home and from his beloved Syl Hellais. She is the first alien child born on Earth, a creature possessed of unimaginable powers. Now Paul and Syl must endure the terrible exile that her race has deemed just punishment for their love. But the conquest of Earth is not all it seems. There is another species involved--the Others--and the Illyri will kill to keep its existence secret.