Three Scorched Kingdoms by Heather Hildenbrand

I was supposed to be planning my wedding, not a war. But here we are.

Escaping Constantine should have been the end of our troubles, but instead, it feels like the calm before the storm. Back in Astronia, the horde is tearing through everything, and I’m stuck trying to figure out how my magic works—fast.
No pressure, right?
Aries is still by my side, the dragon king who’s stolen my heart and set my world on fire—literally. But Constantine isn’t done with us. Not by a long shot. And the trail of destruction and loss in my wake isn’t exactly a confidence boost.
The only question now? Can the magic Aries and I create together stop the war before everything we love burns to ash? Or will the fire between us be the thing that destroys it all?

The third and final book in this steamy shifter romantasy series full of hot dragons, ninja gnomes, and the snarky, magical librarian who started it all.