Realms of the Gods (Immortals #4)
When the barriers between the realms disappear, Tortall falls under deige from all sides. Uusoae, the Queen of Chaos, is waging a war against the greater gods, a fight to end it all. Desperate to save the kingdom, Daine must join the war, for children born of gods tread dangerously in mortal realms. Ages 10+.