Warbreaker is a stand alone fantasy novel by Brandon Sanderson. It revolves around two neighboring kingdoms on the verge of war and the people working to prevent the war.
Spoiler Warning! Below this point there are spoilers!
Susebron - The God King of Hallandren
Siri - Princess of Idris. Youngest daughter of King Dedelin. Wife of the God King.
Vivenna - Princess of Idris. Oldest daughter of King Dedelin.
Vasher - User of BioChromatic magic. Carries the living sword Nightblood. Several hundred years prior to the events of Warbreaker he both started and ended the war that banished the royal line to Idris and began the line of God Kings in Hallandren.
Lightsong - Member of the Hallandren Court of Gods.