Flight of the Nighthawks: Book One of the Darkwar Saga, Paperback/Raymond E. Feist

A portent of annihilation awakens the powerful sorcerer Pug in the dead of night--a dread vision warning of a vast and terrible army descending upon the exposed heart of Midkemia. Even the formidable might of the Tsurani Empire will not beat back the alien invaders. And in far Stardock town, two boys--untrained, unready, and barely come of age--will be called upon by the mysterious Conclave of Shadows to confront a sinister plot that implicates even the highest-ranking nobles in the land. For a nightmare of treason, intrigue, and murder is brewing among an ancient Brotherhood of Death--a clan of merciless assassins whose name is spoken only in fearful whispers...