Nice concept. This feels ominous, like Pyramid Head from the Silent Hill film.
Finally managed to work on the illustration some more.
Started thightening the perspective a bit (not too much yet :D). I decided to make the cathedral background a little assymetrical, as it felt too mirrored, but I'll see where it goes when I actually start fleshing it out.
Also removed one of the pauldrons and tweaked the pose for a better flow (and hopefully a better telegraphed condescending expression). The sword feels too bright and messes with the focal point so that goes on the to-do list as well.
Proper material rendering coming soon 
(Also have to decide on the horn design)
Lookin sick.
I really like this!
You can go nuts with the lighting!
I can even see those rim lights defining the character in the foreground.
I found this .. hope it gives you some more ideas.
https://www.diyphotography.net/howto-dramatic-portrait-lighting-using-nothing-lamps/
Thank you for the kind words!
@nevs38 that was a nice read and is pretty much what I'm going for, thanks 
I am enjoying the idea and colors, but I agree that something like increasing the spike size could help in defining the character a bit more, the simple silhouette does just kind of look like "Guy with a Sword" right now.
I look forward to seeing more!
@PeterH thanks ^^ and yeah, that was my feeling as well. At least I'm mostly happy with the overall look and feel, so accentuating elements and some proportions to make her stand out won't really interfere too much with the illustration.
So here's a version with some bigger spikes and added smaller elements all around, tried making it completely smokey below the waist (like a ghost, but I didn't like it, I want to retain the human inside)
Starting to look really nice!!
Ok, after a break from looking at the character, I decided I can push the shapes even more and add some more flavor elements all around. At long last I'm kind of happy with how the design and the thumbnail sillhouette look.
I'd be happy with some critiques, as I've been looking at her for too long
(Left -old; Right - new)
And another illustration WIP:
A lot of black.
Yeah, you're right I'm planning on making it just 'dark' instead of black but I was still playing around with the design and the focal area (head and torso), general hue adjustments are next on the list. Thanks for the heads-up!
Looking awesome, my only suggestion is about the background perspective, it's too close and maybe could distract a little bit
Thank you , I'll try to push it further back with some atmospheric perspective
After a busy week - finally managed another update!
Most notably (aside from some more rendering :D), I decided to add hair sticking from under the helmet to make her a bit more 'layered' and physical. Some 'exoskeleton' pieces/mech augments were added around the waist/under her arms to go with the helmet (they need some more structure but that'll be the general direction).
Also, I changed the overall ambient hue, faded the background a bit and eliminated most of the near-black colors. I'm also thinking of getting rid of the middle belt knife, because they feel too crammed as of now.
Good idea! It will also add a breathing area.
A few posts back on "composition exploration" you were thinking about mixing two views. I feel enlarging a tad bit your canvas can solves the clogged problem as long as giving you some space to show more of his superpower.
Thanks @innocent , it does feel better when widened a bit. (Fun fact - turns out it was indeed wider in the beginning, but I must've cropped it at some point, as it had the wider sketch outside the canvas XD)
The background finally got some love and attention
Oook, so the composition changed! (a bit)
I was looking at the illustration the last couple of days and something was lacking. I liked most of it, yet I think it became lifeless compared to the first sketches. So I got ye big ol' brush and added some things! It got foggier, more crowded and even wider!
I'll try to recapture and reinforce the feeling of panic and utter defeat of the 'heroes' I think it had in the beginning. I'm still changing some smaller things (mainly effects right now) but I'll upload this just as a general direction. Bigger changes are possible as well but I'll try to keep the things I'm positively liking mostly intact.
Critiques are very welcome
honestly it looks sooo great! the helmet is very well achieved! It has fascinated me!
