Many fan works have recently depicted Yuuka as a bit of a sadist, often being dominant over Alice Margatroid or Tenshi Hinanawi. Yuuka's conversation with Shikieiki in her scenario also suggests that she may be a sadist since she admits she likes to "tease" others daily.
In other fan works Yuuka is portrayed as an insane and bloodthirsty youkai, who kills with a pleasant smile on her face.
Many fans in Japan refer to Yuuka as the "Ultimate Sadistic Creature" (アルティメットサディスティッククリーチャー), or U.S.C. for short.
Yuuka's very low speed (focused and normal) in PoFV and MS has become a small running gag among some folks. There's even a comic in which Aya teases Yuuka with "Speed over Power" while flying circles around her, with Yuuka blasting away to no avail. This even applies to her performance in fangames such as Touhoumon and Touhou Mother in which she has very low speed, but high power.