As promised....
my review, although it may be a little late.
Great pic overall. I like the painting-like look of the background, it really makes the actual chars stand out.
The only tiny little flaw to me is, that there is some kind of sketchy lineart on parts of the left guard and none on the right guard.
Other than that it's awesome.
I had to look up those Nio Guards of course to get an idea of them and I must say, you managed to give them some kind of sublime or even divine appearance. More than most stone statues and paintings I saw have for sure. So that worked out great.
I especially like the perspective, the facial expressions and of course your colours.
Great job!