Rise of the Blood Moon by Alan Gibbons
It has always been this way. The Helati are slaves. Each month, at the full moon, they are expelled to face the demon host, the Lost Souls. But something has changed in the fabric of the times. The demons are controlled by a new master, the Darkwing. Now the danger is permanent, the horror incessant. In a southern port, however, a fourteen year old slave girl, oblivious of her destiny, holds the key to ending the nightmare of the Lost Souls. But will she ever understand the secret that is hidden deep in her memory, the secret of the Black Tower? Alan Gibbons' latest novel is an epic fantasy that takes you through a fabled land, reminiscent of a mythical ancient India. On a roller-coaster ride you will meet shape-shifters, demons, magic, tyrants, an evil lord who is the master of the living dead and countless fighters for evil...and for good.