The original description was that the monster needed to be a giant, fire based, apocalypse monster. The shape size and details were all open season. So I provided the sketches shown here, and they picked the first one, as I suspected they probably would.
After the initial sketch approvals, I sent in progressive shots for incremental approval, something I don't usually do, but it has the added benefit of saving out piece by piece images for me to show how the image came together. This is the color sketch, using just basic shading and coloring to create a rough for the images overall concept.