Yuyuko Saigyouji is a major character from the Touhou Project franchise and serves as the ghost princess of Hakugyokurou, the netherworld realm of the formerly-living. She is a powerful supernatural being who frequently becomes involved in the incidents that occur in and around Gensokyo. Yuyuko is known for her whimsical personality and her tendency to cause supernatural disturbances, often due to her curiosity or desire for amusement. She is typically encountered as one of the antagonists that protagonists like Reimu Hakurei or Marisa Kirisame must confront to resolve incidents. Despite her role as a major antagonist in the series, she maintains relationships with other characters in Gensokyo, most notably her loyal servant Youmu Konpaku, a half-yūrei gardener and swordswoman who serves her in the netherworld.