In an antediluvian world, Keltos warrior Rogan emerges as the lone survivor of a battle. After slaying a Nephilim giant, Rogan takes back the mammoth his folk gifted the kings who started the battle.

Once Rogan learns that his sister is to be a sacrificial bride to the giant, Marduk, Rogan journeys to Irem in the company of Elisa, a warrior herself, who holds a secret. Soon, soldiers are sent to recapture the mammoth and bring it to the Lord of the world, Zazaeil, a demon in human flesh. With soldiers in pursuit, they encounter many evils and monsters. Will the song of Rogan’s blood make him strong enough to be the Killer of Giants?