K.V. Johansen 
Blackdog [EPUB ebook] 

In a land where gods walk on the hills and goddesses rise from river, lake, and spring, the caravan-guard Holla-Sayan, escaping the bloody conquest of a lakeside town, stops to help an abandoned child and a dying dog. The girl, though, is the incarnation of Attalissa, goddess of Lissavakail, and the dog a shape-changing guardian spirit whose origins have been forgotten. Possessed and nearly driven mad by the Blackdog, Holla-Sayan flees to the desert road, taking the powerless avatar with him. Necromancy, treachery, massacres, rebellions, and gods dead or lost or mad, follow hard on the their heels. But it is Attalissa herself who may be the Blackdog’s—and Holla-Sayan’s—doom.