Dogsland Trilogy, book 1: Never Knew AnotherJ.M. McDermott2011

Fugitive Rachel Nolander is a newcomer to the city of Dogsland, where the rich throw parties and the poor just do whatever they can to scrape by. Supported by her brother Djoss, she hides out in their squalid apartment, living in fear that someday, someone will find out that she is the child of a demon. Corporal Jona Lord Joni is a demon's child too, but instead of living in fear, he keeps his secret and goes about his life as a cocky, self-assured man of the law. The first book in the Dogsland Trilogy, Never Knew Another is the story of how these two outcasts meet.