I really enjoy the style in which these were done, it's as though one was fortunate (or unfortunate) enough to come across the "necronomicon" filled with a heirarchy of demons. Very original ideas and designs although demons 1 and 5 are the most startling because they do not have the traditional humanoid physiques, hence I feel they are also the stronger designs. I like the different elements for each demon. I was (and still am) totally blown away, very strong visually and technically. Also I enjoyed the attention to detail, which includes foreshortening, weight distribution and musculature.
With Respect,
R

Damn, I don't know if I saw that first guy in the thread you showed me the other day; He's almost my favourite, methinks.

Really really like the face-inside-mouth thing you've got going on there. I know you seem to be aiming for asymmetry with some of these but in some of the cases (the first one's a bit of an example of this as well) it's detracting from the overall silhouette—he gets away with it mostly because there's a lot of negative space in around him and there's a nice flow to the spikes and arms. It'd be interesting to see a flat front-on of him to see how the limbs balance out (or don't, which of course is not a necessity).

Number II's damn awesome, as I think I mentioned; a good combination of asymmetry and recognisable elements, fricking nice head and mouths... overall I think this guy feels the most solid, but I also think, awesome as he is (do I seem to be using the word 'awesome' a bit too much in a serious art critique?) he's also quite a 'typical' sort of demon-abomination.

Number III's got a great presence but I think his face seems a bit too regular-skull-like, I think something more interesting as with number I or even the less human sort of demon-head thing he's got attached to his arm. One thing I'd also say about this guy is that the detailing on him is all very much the same size, which means nothing on his body really stands out much, and it also means you don't really get any idea of scale from him (because it's all quite chunky; some finer detail would help make him bigger, I think).

Love love the moose horns on Number IV, and he's definitely got a very nicely commanding presence, though if I have to say so I think he's more a demon-lord (or was it prince?) than abomination.

Number V sticks out to me as the biggest offender of the issue with the silhouette; while extra claws and arms can work damn nicely (like I said, number I gets away with it) too much of a good thing doesn't always add to the coolness. That said I really like the detailing on his chest, and the overlapping-mouths thing going on there is definitely worth playing around with more.

Number VI is along the same lines as II, and as such I think he's working pretty well, though there's something off about the shape or perspective of his face-fist which throws it off a little.

I really like the rendering style you're going for with these, though I think a bit more differentiation in the shading of different areas would help draw attention to certain areas of them; while his silhouette's off, the shading from quite dark in the legs up to brightness on his chest and the brighter picking out of teeth and eyes works rather well on V, as compared to fairly similar overall lighting on say IV.

So there are elements of all of them that are working, but my personal preference's for I at the moment

Good luck, and looking forwards to seeing more!