Mysterious, indeed! You did a very nice job with the colors you used to create the mysterious and dark vibe here. Also, the elements provide a great suspenseful atmosphere.
This painting does a good job creating dark and suspenseful vibes, but not much else. If this provided a bigger outlook on what this cult was doing out in this forest, I would score this artwork higher. It just leaves too much to the imagination. If you made this a bigger painting with a more in depth view of what they stand for, it would be much better.