This is a well laid out fantasy with an unusual narrator.  Fintan is a bard of the Poet Goddess Kaelin.  He essentially is the narrator of the Story.   The lands that are illustrated in the book take their Kennings or talents from either the land or the gods of the lands.  It isn’t clear which.  Those on the sea have talents of the sea, those in the forest have talents of the forest.   Kennings are acquired through great sacrifice and there are not many in any country that has a Kenning. 

The story is focused on the Bone Giants invasion but the intricacies are more focused on the individuals and their nations and how they respond to invasion.   The Bone Giant invasion seems to be religion based but that is unclear as they are a mystery to the folks they are attacking.

Fintan starts the story by trying to explain the history of the war to a vast crowd of refugees.  Fintan has a unique way to tell stories that provides a highly realistic story for the crowds.  

Hearne does a nice job and allows his story teller to provide a lot of depth on characters with an explanation as to why he is doing so.  He also points out the irascibility of both nation states and leaders and how that can lead to tragedies.

A good book, I recommend it.

Web:  https://kevinhearne.com/