I love the improvements and tweaks from your original reference sheet. I think what mostly brings about the "intimidating" factor is the improvement in muscle and gore apparent in his reference sheet. It was there but the fact that you made it seem even more real in this drawing makes him much more gruesome features. I love that he has three ears as well.
Also the matte finish of the drawing gives it a high quality and the hazy features of his wings and slithering body just add to the overall gruesome persona, as if he is slinking in the middle of a cold, rainy night hiding in shadows and seeming to be invisible. The only time it becomes apparent he is right beside you is when the lightning flashes. Wonderful work; it has a lot of great things going on at once, some implied, some in the craftsmanship of your digital work ethic.
You are quite welcome. I had seen the old reference sheet before but I could not remember exactly what he looked like before the reworkings so it was fun going back over it. c: I cannot wait to see more of him in your work. Ah, then I look forward to seeing a re-vamped reference sheet in the future.
He is a unique character that is for sure!
I was your 25,000 view c:
Also, this is a beautiful peice of work, smooth, and not rough at all C: <3333