Yuuka Kazami

Yuuka Kazami is a youkai called the "Flower Master of the Four Seasons." She first appeared in Lotus Land Story as the fifth and sixth stage bosses (at that time, without a surname) as well as a playable character in Mystic Square. Afterwards, with her canon completely remodeled, she appeared again as a playable character in the ninth work Phantasmagoria of Flower View. Though her exact age is unknown, there are many hints throughout the games and printed works that she's actually an elder youkai who's lived a very long life. Many fans in Japan refer to Yuuka as the "Ultimate Sadistic Creature" or USC for short, often portrayed as being dominant over Alice Margatroid, Wriggle Nightbug, or Tenshi Hinanawi. Yuuka's conversation with Eiki Shiki, Yamaxanadu, where Yuuka admits she likes to "tease" others daily, is sometimes used to speculate that she may be a sadist. In other fanworks, Yuuka is portrayed as an insane and bloodthirsty youkai, who kills with a pleasant smile on her face. Thus, she is commonly called a Do-S where "Do" stands for "dreadnought-class" and "S" normally stands for "sadist"). However, she is also sometimes portrayed as having a soft side, in which case sometimes people joke that the S stands for "shinsetsu" instead, which means "kindness" or "gentleness." (Source: Touhou Wikia)