A Sky of Spells (The Sorcerer's Ring #9) by Morgan Rice

In A SKY OF SPELLS (BOOK #9 IN THE SORCERER’S RING), Thorgrin finally returns to himself and must confront his father once and for all. An epic battle occurs, as two titans face each other, and as Rafi uses his power to summon an army of undead.

With the Destiny Sword destroyed, and the fate of the Ring in the balance, Argon and Alistair will need to summon their magical powers to help Gwendolyn’s brave warriors. Yet even with their help, all could be lost if it were not for the return of Mycoples, and her new companion, Ralibar.