Wrath (The Faithful and the Fallen #4)

Events are coming to a climax in the Banished Lands, as the war reaches new heights. King Nathair has taken control of the fortress at Drassil and three of the Seven Treasures are in his possession. And together with Calidus and his ally Queen Rhin, Nathair will do anything to obtain the remaining Treasures. With all seven under his command, he can open a portal to the Otherworld.