Hello! It's an heavy guy you have here.
I like A, it's straight to the point (without the horns). The main idea of the mouth on the torso, which is cool, is not enough readable probably because of the shape/orientation of the teeth.
Maybe you can draw teeth more like rocks or jaw like those machine to crush cars, you get the idea.

There’s a lot of interesting varied designs here.
The T-rex bodied demon concept shows a lot of strength, kind of bulked up and intimidating with the shape design so I think the idea is coming across pretty well

Really cool designs Edgar! I prefer the C option. That tongue is very sexy and adds an extra appeal

Haha when the ideas are popping out .
Start maybe with a more analogic palette and then add an accent with a complementary and see where it goes.

Really liked the A on the previous concept btw.

Hi! B is the more ready to go if you play more with your lights. D has an epic Darth Vader vibe. Storytelling-wise C sounds interesting, looks like he hasn't found his valentine's. A would be probably more interesting in a horizontal format.

Oh snap! O.o That latest sketch looks freaking cool! :V

looks sweet dude, specially the light hitting that foot xD
You could try bringin some darker shadows into the foreground tentacles to push the depth. The orb in the background also reads more like a flattened sphereoid at the moment, i think whether you want it to be like that or a full sphere you could put some more defined reflections and highlights to emphasise it's form: https://images-na.ssl-images-amazon.com/images/I/41DmgRIRPOL._UY395_.jpg