The World's Finest Assassin Gets Reincarnated in Another World as an Aristocrat [TV]

The greatest assassin in the world is reincarnated as the eldest son of an aristocratic family of assassins in a new world. However, in exchange for his reincarnation, a goddess gives him a mission: to kill the prophesized Hero who will bring about the end of the world. Utilizing the knowledge and experience he gained from his previous life and the techniques and magic of his new family, the assassin becomes the most powerful assassin in the fantasy world.