Xuan-Yuan Sword (Chinese: 軒轅劍, literally "Sword of the Xuan-Yuan")[1] is a long-running historical fantasy role-playing video game series developed for personal computers by the DOMO Studio (DOMO小組/多魔小組) 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" (大宇雙劍) 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.
A recurring item of the series is the Monster Fusion Vessel (Lian Yao Hu, 煉妖壺), created by the goddess Nüwa in emulation of the Immortal Creation Ding (造物仙鼎) to cleanse the world. Within the Vessel resides an immortal entity known as the Spirit in the Vessel. The Vessel's powers are to absorb nonhuman creatures, and to transmute them into other creatures or items.