Ossan, Yuusha to Maou wo Hirou

After being forced to retire from his guild due to his advanced age, adventurer Allen Holder finds two babies with strange birthmarks alone in the forest. One is a prophesized hero chosen to save the world, the other a young demon destined to become the ruler of her demonic brethren. Although the prophecy clearly puts the two infants on opposing sides, Allen raises them side-by-side and treats both of his adopted daughters with love, determined to keep them safe and hidden from those who would exploit their power. But as Lusha and Luna grow older, the outside world begins to encroach on their peaceful lives, demanding they fulfill the roles of their birth. Can Allen protect his children from a destiny that would only bring tragedy to their happy family?