He has a bad boy look. And I'm sure he's a bad boy. 'Cause good guy do not attempt to poison other people... Do they ? xD
But the true question is : Who is he going to kill ?
I love the artwork. The snake is the only "flashy" element in the piece (with the lights). And it's the first time I see a painting where the murderer uses directly the snake to poison the knife. I just love it.
I'm glad you like it. And I don't really know who he's going to kill. Most likely someone important. And also someone who lives in a stone castle by the looks of it. A king is too cliché, so let's go with a duke or a lord or something.