Let's start the week with some fan art... and a little puzzle!!

This very cool picture was drawn by a fan of my books with the Twitter handle of EmoNobody. The characters never met in their respective story lines, because it's a mash-up of two different series. So the puzzle I'm setting for you guys is... which two characters are they?!? No clues -- I wouldn't want to lead you down the wrong path! Oh wait -- WAS that a clue?!?

Have your best guess, and I'll be back with the answer later today. :-)