This started as a quick sketch of Obi Wan (the Ewan McGregor version) before I decided that it looked cooler with inks applied to it. The shadows definitely give more drama to the scene.
It also tends to frame his face better. I have said in the past that likenesses are not my strong suit. Fortunately, shadows tend to hide those flaws while giving you more realism in the picture.
If I had one complaint, I am looking back at the picture, I wished I didn't make Obi Wan's left sleeve so weird looking. I meant to give it wrinkles, but it looks more like "ribbed for her pleasure" if you get my meaning....