The world’s top assassin, renowned for his deadly skills, meets an unexpected end in the modern world, only to be reincarnated as the eldest son of an aristocratic family of assassins in a new, magical realm. Upon his reincarnation, a goddess gives him a singular mission: to kill the Hero who is destined to bring about the world’s destruction.

Equipped with the wisdom and experience from his past life as the ultimate assassin, and armed with the ancient techniques and magic of his new family, he embarks on his mission. The combination of his previous life’s modern assassin skills and the newfound powers of this fantasy world propel him to become the most formidable assassin of all time. With his new life tied to this critical mission, the assassin must use every resource at his disposal to carry out the goddess’s request and prevent the foretold catastrophe.