You're off to a good start. A lot of people have trouble drawing figures, but the overall proportions here are pretty good. The composition travels nicely up to pipe to his face, then along his arm with the elbow bring you back in to the table and to the pipe again. The pipe itself is well executed. That sort of symmetry is relatively difficult (at least for me), and the values give it a nice metallic look.
While I like the composition, I think the format (size and shape of the paper) could fit better. His left arm is almost parallel on right on the edge of the paper. I wouldn't want to crop it off. On the other hand, if the whole image moved to the left, his face would be much closer to the other edge, and then it might start to feel cramped as he no space to gaze into. I think the image would be happier on a format that was a little shorter and wider.
There are still a lot of very hard outlines in the picture, particarly on the headdress, and the top of the pipe, that I find distracting.
The overall sense of light in the piece is not strong enough to justify the far side of his face that deep in shadow. Try lifting out a bit of brow and cheek to make it reappear over there. Or, if you want to be mysterious, strengthen the light gradient across the rest of the image to match. A minor nit: his moustache should follow his face around and back into shadow on the left (his right); this one is too frontal.
Another minor drawing nit: the forefinger of his right hand, holding the pipe, is too long in the segment closest to his hand.
Look closely at the highlights showing the knuckles there.
You seem to be a bit afraid of the outlines you established, and the values don't always come up to them. Notice around the chair, or the bottom point of the headdress, how the dark stops short, leaving a gap before the line? Charcoal's not exactly a precision medium, so don't worry about running over. You can always lift it back out (except for the utmost lightest light). You might want to try a tortillon, which is that paper cylinder sharpened on one or both ends, to give you control over rubbing in tight corners, if you're not happy with your fingers.
The perspective on the rattan table doesn't match that of the pipe. It's at a more vertical angle. The diamond needs to be narrowed from top to bottom. I hate to redo it, since it has a nice suggestion of texture without being bogged down in details. I also like the way it helps establish the light, with two of the sides developing shadows on the individual strands, while the other two sides parallel to the light are lighter.
Really dark subjects can be tough to handle. (See some other messages, about a horse in watercolor, or a more recent one with a black rabbit and white cat). Even with black, some parts are darker than others, and the lights can well be nothing like black at all. The lower part of this picture could have more definition on the legs and torso, again to help establish the light. His leg also disappears behind the table, where it's all light back there.
What about the background? Lights and shadows for mystery, or more details of his place and time?