“Ultimate Sadistic Creature” (アルティメットサディスティッククリーチャー) is a fan interpretation of Yuuka Kazami from Touhou Project, portraying her as a sadist to go with the Masochistic Tenshi theories. As for the name, it can be traced back to a fan comic published on May 14, 2008.¹⁾

The term stems from the Touhou Acrobatica (東方アクロバティカ), a fan comic by “Ore to Umi” (俺と海), where Kanako smacked away Cirno's frozen frog dango offering,²⁾ so Cirno cries to Yuuka who glares at Kanako, then Marisa comments that the 'Ultimate Sadistic Creature Yuukarin' took an interest in her.³⁾ The nickname is possibly a reference to Aptom, the 'Ultimate Battle Creature' from Bio Booster Armor Guyver.

With the release of Touhou Hisouten and rise of the Masochistic Tenshi theory, people wanted a sadistic foil and landed on Yuuka,⁴⁾ who had been described as a 'very strong' youkai up to that point. Much of this fan interpretation relies on her PC-98 past, where she had a long history of verbal abuse to provoke, but it meant that her playful teasing would be flanderized into outright bullying.

• This considerably long name has been abbreviated as 'USC' in the Japanese language.
  • However, this can't be used in English as the 'USC' abbreviation has other connotations, such as: USC Trojans, USC Spartans, HK USC, Unnamed SDVX Clone, etc.
• There is a proper Japanese kanji rendering, 'Kyūkyoku Kagyaku Seibutsu' (究極加虐生物), but this is seldom used, plus this would probably be read as 'Ultimate Sadistic Creature' anyways.
• You can find better ships than Yuuka/Wriggle and Yuuka/Tenshi, come on.

• Masochistic Tenshi - Point of origin. Arguably caused this fan interpretation.
• Sadistic Sanae

• Ultimate Sadistic Creature on Pixiv Encyclopedia
• Ultimate Sadistic Creature on Niconico Encyclopedia