Centuria is an action-packed dark fantasy manga that follows the journey of Julian, a runaway slave who escapes a life of bondage aboard a ship carrying 100 other enslaved individuals. His life takes a dramatic turn when a mysterious sea monster grants him an extraordinary blessing. After escaping, Julian takes responsibility for Diana, the infant daughter of a fellow slave who entrusted her to him. Together, they attempt to forge a peaceful life in a world filled with dangers and prophecies.

The narrative delves into various arcs, including confrontations with mythical beasts, struggles against oppressive forces, and the emergence of Diana as a pivotal figure in an ancient prophecy. With themes of survival, sacrifice, and destiny, Centuria explores the moral complexities of its characters as they navigate a cruel and fantastical world.