This piece is absolutely stunning! It is very realistic; the muscles, the bones. You have even managed to make the hands look like hands. I have noticed that a lot of people struggle to make hands look real, but you have done a marvelous job.
I love how you have each male looking distinctly like his own person; for example, Harry has a different face than Draco, and you have made that clear. I love how I can clearly see different expressions on each face as well; depicting each character's personality.
I find the poses realistic and easy to imagine being done.
You have done well on the torsos, making them muscular without being overly so.
All in all, I have nothing but praise for this piece. You have done well, and shows.