Book Wrath of the Dragons — Olivia Rose Darling

Cayden Veles, renowned Demon Commander turned King of Vareveth, overthrew the throne to save Elowen Atarah, the woman he searched for since childhood. Now he's determined to fulfil his quest for revenge against her father, even if it means forcing the only person he's ever wanted into a marriage of political convenience.
Elowen Atarah has everything she thought she'd ever want. Finally reunited with her dragons, she now has an army to enact vengeance, but as events transpire, she begins contemplating if she wants more. As her father's only living heir, the Imirath throne is her right and destiny. But fighting and winning a war will require trusting Cayden Veles, her partner in crime and now king to her queen; the man she both longs for and doubts, especially after opening her heart only to become a pawn in his game.
Navigating the shifting allegiances among all the kingdoms of Ravaryn will require all their strategy and strength, with devastating and bloody attacks on one side and cut-throat diplomacy for alliances on the other. But Elowen and Cayden must find a way to stand strong within the power they've gained, or risk losing everything.