The Fox Sister (Korean: 여우 누이; RR: Yeou nui) is a Korean folk tale[1] about the mythical Korean nine-tailed fox demon (kumiho). The tale follows the story of an old couple, their sons, and their beloved daughter, who is later revealed to be a fox demon. The fox sister eats the old couple but is later defeated by one of the brothers, who receives magical items from a supporting character.[2] According to a 2021 study, at least 75 variants of the tale exist throughout South Korea, with varying details on how the fox sister is defeated, or from whom the brother receives the magical items.[3]