@Ropponmatsu: Her original description is "優雅でゴージャスな美しき悪女"
I might have gone with "Elegantly gorgeous, beautiful bad girl."
"悪女" seems to be one of those words that varies its strength and meaning depending on the context, age of the speaker, etc. Obviously the kanji are literally "bad" and "girl." I've also seen it translated as "bitch," "wicked woman," "ugly woman." I sense that Kishi-sensei did not intend it to be a harsh pejorative like that (none of the characters are really bad or unsympathetic, even Kaoru, despite her haters here), and Dr. Mario went accordingly with a more playful translation to capture both halves of "美しき悪女" in one word.