Eminently Elf by Jessamyn Kingley

Emperors Chrysander and Ellery Draconis are in love and looking toward the future. Ellery is the first hybrid to survive a dragon shift, becoming a legend. Chrysander couldn’t be happier with his elf dragon, and for the first time he is truly savoring life. Despite the demands of their schedules as the leaders of the Council of Sorcery and Shifters, the pair have also managed to find balance. But not everyone is happy to see the leader of the dragons with a half-elven mate.
As the two go about their daily business, those sworn to protect them work tirelessly each day to ensure the safety of their emperors. They lived through the horror of the previous rulers being murdered and are all too aware of the dangers that lie in wait. Nothing is left to chance, but regardless of their dedication, not even they can prevent evil from rising from the mists.
On a seemingly ordinary day, an unexpected attack shocks everyone. A matebond is taken to the brink and the limits of magic are tested as the strongest forces unite to try to repair the damage. It will take time, patience, and perseverance for good to prevail. Chrysander and Ellery will once again overcome the odds and emerge victorious, but in the end, nothing will ever be the same.