If I didn't know any better, I'd thought this was a guy.
Well, Koakuma's decidedly non-busty and short-haired in this pic - it could very well be so. I'm not quite ready to tag genderswap, but I will tag androgynous.
(The commentary isn't likely to be much help - the gist of Google Translate is that it's basically a "thanks for all your hard work" sort of thing - and the author-added pixiv tags are just 東方 (Touhou) and 小悪魔 (Koakuma).)