Rhythm of War (Signed Book) by Brandon Sanderson

After forming a coalition of human resistance against the enemy invasion, Dalinar Kholin and his Knights Radiant have spent a year fighting a protracted, brutal war. Neither side has gained an advantage.

Now, as new technological discoveries begin to change the face of the war, the enemy prepares a bold and dangerous operation. The arms race that follows will challenge the very core of the Radiant ideals, and potentially reveal the secrets of the ancient tower that was once the heart of their strength