Showing Light My Fire by Katie MacAlister

Aisling Grey is juggling being a demon lord, a Guardian, and a wyvern's mate, even though she's keeping her distance from said wyvern, Drake, these days. But her presence is still required at a meeting of the green dragons. Since several attempts have been made on her life, Drake is sure to get protective of her. Which might not be a bad thing when war breaks out and all hell breaks loose-literally.