Starred Review. The rousing fifth installment of Butcher's military fantasy cycle (after 2007s Captains Fury) finds the land of Alera recovering from Lord Kalaruss rebellion, an invasion by the wolven Canim and a bloody slave revolt. Now a new threat emerges: the all-devouring insectoid Vord, who have learned to control the elemental furies that once protected Alera. Young Tavi of Calderon, recently recognized as the heir to Aleras throne, fights seasickness and interspecies hostilities escorting the Canim invaders back to their homeland, only to negotiate a fragile alliance with them against the Vord. No less powerful than his intense battle scenes, Butchers vivid characterizations, based on ancient Roman Republican ideals, range from duty-honor-country austerity in battle to brilliant peacemaking, noble self-sacrifice and Tavis coming-of-age as a wise Marcus Aurelian ruler