In order to protect the lands of humans from the Demi-human tribes of the macaques and orgs, a young boy named Kai rages onto the battlefield. In the midst of a battle one day, Kai suddenly remembers memories of his past life. Memories that are more advanced than the world he currenlty lives in. Kai returns safely to the village and begins to recall his memories, awakening new powers along the way, but soon after, finds himself in a deadly battle with an org after receiving a near-fatal wound... In a world where humans, Demi-humans, and gods mingle, a story of a young boy's battle and growth unfolds!

(Source: MangaPlaza)