Obsidian Wraith fantasy novel by author Nathan Wilson and S. E. Nin

As samurai clans feud over the Imperial Throne, a temple scribe named Shindara is plunged into the fire and ashes of the Genpei War.  Torn from his home, he unwittingly falls in with a group of bandits who may end up teaching him more about life and death than his high priests ever did. 

While living among the bandits and warriors, he gains two close friends... a merciless thief with a loyal streak and a fallen princess-turned-rebel leader.

 

However, the war may be the least of Shindara's troubles. With every passing day, a curse is eating his soul and drawing him closer into the dark realm known as the Yomi.