Dark Lady (Chibi-Usa)
I styled my avatar to look like Dark Lady from Sailor Moon. This is when Chibi-Usa becomes evil.
You can watch this youtube video if you're interested in her:
I know her dress doesn't have all those fancy jeweling on it, but it was hard to find a long black dress that flowed into another color at the end. Also I don't think there is a black crescent I could have put on the head so I went with Path of Luna to have a moon on her forehead at all.