Despite his privileged birth, a man with strained family relationships is reborn into a magical world where the empire controls the entire continent. Reincarnated as the eldest son of the emperor, Archa, he isn't the legitimate heir. Instead of striving for the throne, he decides to focus on building a close-knit family, something he never had in his past life. Shunned to the edge of the palace, he pursues alchemy as a hobby, even creating a sentient being named Sephira, defying scientific understanding. While he wishes to enjoy his freedom, the nobles are suspicious of the emperor's eldest son and constantly interfere. Archa, often pretending to be a child, navigates these challenges, all while expanding the possibilities of alchemy. This story features a weak protagonist who doesn't aim for the emperor's position, avoids violent revenge, and includes interludes every five chapters.