very nice drawing, the portrait looks great and the level of detail is astounding.
maybe a few remarks, (if I'm allowed to make them ;) )
the drawing (and several other in your portfolio as well) looks like its three distinct drawings/ styles to it; the face, the figure/ body & raven, and the background.
all these have a different set of tonal values, level of detail, highlight structure and overall appearance. This gives the drawing a bit of an unfinished look. the attention is primarily on the face and less on the drawing as a whole. I would focus more on the harmonizing the different elements of the drawing in one style.
also don't be afraid of usine black, the darkest darks are of uniform "blackness" , but right now have several different lighter grays.
last one do'n't forget the direction of the light source. The shadows on the hilt of the blade have a different angle than on the face.
hope this helps you a bit,