Xuan-Yuan Sword (Chinese: ??? literally "Sword of the Xuan-Yuan") is a long-running historical fantasy role-playing video game series developed for personal computers by the DOMO Studio (DOMO??/????) of the Taiwanese game developer Softstar Entertainment. The games incorporate heavily elements of Chinese mythology and is one of the so-called "Twin Swords of Softstar" (????) along with The Legend of Sword and Fairy a sister fantasy RPG series also developed by Softstar. In time immemorial the titular Xuan-Yuan Sword was wielded by Yellow Emperor to defend Ancient China against the warlord Chi You and his aggressive subjects. After Chi You's defeat the future for the five-thousand-year-old history of China was secured and the sword was passed on from Yellow Emperor to future generations to continue to defend the world against evil. Due to its great power the sword was often sought by treacherous individuals to further their own ends.