Fatal Desire (Guardians Series, Book Two) by Valerie Twombly

Caleb is dark, hot, and commanding in human form. As a dragon, he’s a force to be reckoned with. When he witnesses the slave Lileta being beaten by his Overlord Odage, he nearly comes unglued. Without understanding why, he asks to take the slave as his own, but soon realizes his longing is more than an attraction to a beautiful woman. In a sick twist of fate, the gods have given him a demon as his mate—one he can never touch unless he wishes his own death. His only choice is to grant her freedom…