The superb detail, from facial scarring to the soles of the shoes, and the way the personality of each character is so perfectly captured in their facial expressions and posturing, it's like Guang Yang has not only mastered 3d art but caricatures and life drawing as well. Check out the scene breakdown at the link below.
Link --via BuzzFeed
So it's 3D. Perspective and foreshortening have been standard techniques in western art since Giotto. Any competent artist could easily render an equivalent image in a variety of materials. Acrylic for one, for that shiny, superficial appearance.
Reference the photo realists, or commercial illustration for example.
That site is awash in 'big breasted warrior girl' and 'well endowed samurai girl'. This is very refreshing. Go Zbrush, go.