Very interesting composition. Idk if it's intentional, but it demonstrates a yin and yang dynamic between the characters it features. And not that surface-level "good and evil" that people pretend yin and yang means, the character in the bottom left is followed by flowers, which normally makes you think of life and warmth, but they have a sinister expression, which makes me think they have more going on than just a binary alignment. There's a similar effect with the guy in the top right, he gives off an air of menace, goatee and everything, but his expression and placement on the lighter side of the image make him feel less threatening than the other guy. He's certainly not someone to mess with, but he's not as hostile as he looks. And the two characters in the middle seem to be the protagonists, maybe rivals, and their placement makes me think they'll both struggle with the complicated duality expressed in the rest of the artwork. Your techniques with the lighting and shading really work to drive home that point, and the colors add to that contrast you're going for even more
And something I just noticed as I'm writing this: the background on the left looks very industrial and crowded while the right side is very simple and natural. So if I had to hazard a guess at the themes of your story (and sorry if this is way off), I'd say it's about industrialism and naturalism and how the "true face" of those who believe in either one may not reflect what the ideology represents at a glance. Perhaps it even blurs the lines between the two, making the protagonists and readers question which one would really be better both in the context of the story and in the real world and wanting to find a good balance.
Maybe it's not that deep and I just need to read the story to understand the cover, but that's the impression I get from looking at it. I'll definitely give it a look tho to see how right or wrong I was :3
