Evil Never Looked So Smexy

I don't know how to start this, but let's just begin with the composition.
The composition you choose to focus on their faces are quite unnerving to begin with. It screams your lack of ability to create background. Furthermore, it seems that you haven't even put perspective theory to begin with. The person who's behind the white-haired man face is in front of his face, wheras his body is behind it. This, my friend, lacks physics, and everything real. I'm not talking about the character itself, but the way you create the image.
Second is anatomy. Now, don't you scream by saying, i don't need to know anatomy, blablabla it's my style bullcrap, because you do need to learn it. The face is all crooked up, and.. don't let me start with those disporpotioned eyes.
Third, learn how to paint, because those paint doesn't spread well. It seems that you use too much water and the paper quality does not match the media you use to create the image.
It's a good thing that you ask for critique, because you need one.