Shiina Kazuya, who was stabbed to death by a thug while protecting his childhood friend's sister, is reborn as Cain, the third son of a noble family, in a world of swords and magic that he has always dreamed of. In this world, it is customary to receive a blessing from the gods at the age of five. However, the power of the blessing is so immense that it results in something beyond the boundaries of the world...