I get sad, impressed and excited when I see a piece like this with a description like the one you've given.

Sad: Because what you've done in 30 minutes is what I might be able to achieve in a day or two (but that's why I keep practicing :))

Impressed: Because the paiting, the brushstrokes, colorpalette, clear and conscious choices where to put detail to give depth are all spot on.

Excited: Because it all comes together ito such a nice, atmospheric piece! As I said, the choices where you've put emphasis on detail really pushes the arm into the foreground and the face into the background. Still the natural focalpoint is on that amazing helmet and there is such a nice threading of where you've put highlights and shadow that I sense my brain adding pieces to complete the charecter in spaces where there is only black. Amazing work.

My main grudge is that you only spent 30 minutes and that's why there are areas that could be refined more. Motivation to 4.5/5. Really cool though.

This is a really cool image for several reasons,
1. The charecter looks so asexual, you titled it demoness, but due to the chin and small breasts it could almost be a male also. Since demons are... well demons. I actually think this estitic is much cooler than either the really muscular or extremly busty versions that we typically see.
2. The design of the charecter, the clothing and little details like the pendent and accessories on the horns are really nice.
3. Executionwise I love this type of brush, its coarse and there is meaning to every brushstroke, nothing is done without intention. Usually makes the piece very organic. What I'd wished however, is that you'd added a bit more detail, or finer quality to the face to give a natural focal point there. With the current composition there is already a natural focalpoint on the charecter herself as she sticks out so much from the background. However, I'd liked to be sucked more into the eyes. Although this is personal preference it is still my motivation to 4.5/5 since I feel a bit more could have been done.
4. The lighting is nice and atmospheric, had been awesome if you had just painted a small white square up to the left of the charecter like a door and then that she is standing in this wast nothingness. Had given a really creepy vibe I think but also a lightsource and depth to the piece.

However, overall, amazing work. Love it. Please give us more! :)

Interesting, creepy charecter. I like the overall brush of the image. The colors blend nicely and even though there are some construction lines left, you've managed to remove most of them through the brush. The background and rock also look really nice, especially the clouds.

Looking at the charecter, my main grief with it is that the beak looks like a claw almost. This might be intentional but if not I'd liked to have seen some more shading around the "lower" part of the beak. Hence, adding a shadow under the upper part of the beak and rounding off the lower part of the beakwhere it meets the head (Motivation for 4.5/5)

Otherwise the image looks cool, nice a creepy also with the wound in the chest, almost as if it was a zombie bird. Well done