This is an interesting interpretation of Melkor/Morgoth. It's been a while since I've read the Silmarillion, but I've always pictured him as being more hideous looking. This actually makes Morgoth more unsettling and it really works. Good job!
This too is perfect- I particularly like the suggestion of a dark crown -and it is fire and sparks and dark matter, like space- it suggests that he has deep understanding of dark matter, science, curvë. And the eyes are amazing- cold and rather scary.
Another of my favourites, your Melkor looks both handsome but malevolent. The sweeping lines in your work really make your work pop out in the thumbnail section. And the light on one half of his face and the other shadow.... nice! You have a good eye for laying out pictures so they are not only technically correct and super-beautiful but the way you lay out of your images keeps making me want to keep looking at the pic.