The Kingdom of Gods by N.K.Jemison

This is the final volume in The Inheritance Trilogy, and the longest.  In this volume, the story is told from the viewpoint of Sieh, the trickster godling, son of Nahadoth.  The story begins as Sieh returns to the castle of the ruling Arameri family and encounters two six-year old children, Shahar, a girl, and Dekarta, a boy.  In this chilling encounter, Sieh tests the children by threatening to kill Dekarta, but Shahar wins by using her wits.  In return, Sieh grants them a wish, and to his surprise they wish to become his friends.  But as they swear the friendship oath, Sieh is very damaged and changed from a god to a mortal, We later find out that the two children are both themselves part godling, and therefore their blood is toxic to other godlings. The rest of the story follows Sieh as he attempts to regain his status as a godling, but also learns what it is to be a mortal.  The story culminates in a grand battle among the godlings for dominance and destruction of this universe - to determine the ultimate inheritance of this world.  Jemison explores many large themes in this trilogy, from what is it to be human to how do the spiritual and physical worlds coexist.  I found the plotting to be a bit confused at times, as characters that played major roles in the first two books were left behind for other viewpoints in the second and third volumes.  Still, this is an engaging fantasy trilogy if you don't analyze it too much and enjoy the author's excellent description, dialogue, and scene setting.   539 pages.