To Wear a Demon Crown (King and Coven #3) by Madeleine Eliot

After suffering a great loss, Elara is finally ready to embrace her power and take on the Crone.

With new magic emerging and secrets about her parents’ pasts finally coming to light, Elara is tasked with fulfilling a prophecy a thousand years in the making.

But when shadows rise to threaten Carnon’s rule over the Darklands, Elara must embrace her place as Queen and enlist allies—new and old—to thwart the evil threatening her borders and unite the realms divided for a millennia.

To Wear a Demon Crown is the third and final book in the King and Coven series. It is an explicitly spicy romantasy featuring fated mates, found family, animal companions, and revenge.