It's gorgeous though it's her expression of concern/worry more than confident wickedness that might keep it just shy of 'horror'. Unless she's horrified by something only she can see, because at that point...Nailed it!
It's a beautiful piece of artwork, the dress is stunning. The girl seems like a character that would have a very amazing story, and her expression speaks volumes. Fantastic. It is a picture that I could easily build a story around, which is always something great. Keep up the amazing work, and this is by no means a fail!
I really like this picture; I love how beautifully you captured the coloration of the skin and that armor has a wonderful mix of fantasy trope "skin armor" while at the same time not giving away too much. (at least, not from this angle) I can only imagine how difficult it is for her to get her hair to do that, however; I hope she has some form of magical servant to help.
I think you succeeded in your goal to make this one a bit different and darker than a lot of your things. The face is always the most important part of a more serious work with realism and seriousness in the expression. Good job.
Well, the outfit may work for a "dark" concept... But facial expression and surrounding just give the vibe of a different kind of emotion :\ Well, I find it really good anyway, but that's another story