This is amazing and terrificly detailed work.
The way each scale is shaded and drawn to flow with the highly imaginitive anatomy.
The wings are most eye catching to me along with all the bits and bots of knight's armour scattered around it's feet.

The blood staining in the piece is excellent, I suggest using more shades of red for the blood to give it a more realistic view.
The only other things i can pick up on, is the background. The clouds which could do with a bit more attention with shadows and highlights.
I especially love how the moon is shining like that.

Great work!