Rhythm of War: Book Four of the Stormlight Archive (The Stormlight Archive, 4)

Rhythm of War continues The Stormlight Archive saga. After forming a coalition of human resistance against an enemy invasion, Dalinar Kholin and his Knights Radiant have spent a year in a protracted, brutal war with no clear advantage for either side. The threat of betrayal by Dalinar's ally Taravangian complicates every strategic decision. New technological discoveries by Navani Kholin's scholars begin to shift the war's dynamics, while the enemy prepares a bold operation. An arms race ensues that will test the core ideals of the Radiants and potentially uncover secrets of an ancient tower once central to their power. Kaladin Stormblessed faces changes to his role within the Knights Radiant, while his Windrunners confront a critical problem: as more deadly enemy Fused awaken, honorspren refuse to bond with humans to create additional Radiants. Adolin and Shallan must lead the coalition's envoy to the honorspren stronghold of Lasting Integrity to convince the spren to join the fight against the god Odium, or face the consequences of failure.