Ullr's Fangs: Book Two of The Incarn Saga

"According to legend, when the world was young, two gods of war — one male, one female — were destined for each other. Yet Ullr, forever unfaithful, lost the love of Issaura, his true match, and was forsworn. His violent anger and bitter rage grew and intensified, poisoning all creation and humanity.Now that the Raiders’ long ships have faded from sight, the kingdom of Elysia is beginning to recover from the summer’s war with the brutal invaders from across the sea. Yet darker forces have taken root, forces that can alter the future of the land and its people in unthinkable ways. Seventeen-year-old Lluava must discover the means to prevent her world from collapsing. But in doing so, will she succumb to that darkness?"