Stone Serpent. The Cataclysm Trilogy, #1

Buried secrets. Unspeakable horrors. Fifteen years have passed since the Great War and the ancient land of Kenetchi is in ruins. Ta, a peasant's son, born to a dreary world of landlords and rice paddies, dreams of becoming a warrior. When he learns that his father is the keeper of an ancient sword once carried by the legendary hero, Chan of Sarakand, have his dreams been answered?But with the sword comes the voice calling from the forbidden hollow hills, the voice of an eldritch monstrosity that feeds on ruin and will make Kenetchi its feast.