I've looked over the entirety of the series. I think all of it is fantastic, I've decided to focus on this piece though because this was the first one I found. The musculature of the figure is very detailed, and more importantly, quite accurate. The background is quite stunning, but doesn't draw focus. If I had any constructive criticism it would be that on this particular figure, the face seems a little delicate in relation to the body, also, the bracer on his shoulder seems a tad out of proportion.
My main grief with these is though, you've stated explicitly on all of the pieces in the series, that they have been created for a fantasy world, but there is no details on said world, or the characters place within it, or even a brief history of them! That would really draw me in personally