Sorry, but this is not good at all. The render sticks out way to much, and the bright lights over power the rest of the background. I did however notice the faces incorpoated within the background, and give you some credit for that, as it looks cool. Change the render, and you may have something nice.
Render is too saturated with color, the white flames coming off him don't really help with the current color scheme imo, but other than that, it looks like progress KiU
My suggestion is to look up a tutorial on blending. It would look generally a lot better if it was blended with the background and had a specific flow point.