Yuki (ユウキ, Yūki) was the guise of the sea cucumber Fangire named Thorn Fangire (ソーンファンガイア, Sōn Fangaia), a member of the Aqua Class and the Queen of the Fangire in the World of Kiva. Her true name was Perishing at the Altar, Silence from a Deep Kiss (滅びゆく祭壇に、沈黙より深いキスを, Horobiyuku Saidan ni, Chinmoku yori Fukai Kisu o).

Though she supports Wataru, Yuki sides with Apollogeist, marrying him to give him immortality so she can have a place in Dai-Shocker.