At the moment I'm designing a very simple webcomic. The main character, Lucifer, or Lucien as he prefers to be called, converses with God, who is represented by a glowing ball. That's right, only one character to design and at the moment he remains in the one location, so only one location to design. The emphasis is on the conversation between the two and their gesture. Plus it means I can manage this project more easily to fit between my many university assignments.
Lucien
Fairly physically immature and greatly misunderstood demon type character as in the beginning of the comic he is suddenly borne into existance. By mortal standards, he'd be an young teenager. For that reason I have to draw him young with short, stubby horns on his head. His hair is messy considering he spends most of his life in a rather hot place. I'm giving him hoofs for hands to further the "Devil" look, but still giving him a flesh tone. For clothes, he will wear a dark leather outfit made from the flesh of the dead mortals that surround him.
God
It is common for people to avoid depicting God since there is so much contraversary over Him. I chose a glowing ball of light to depict him. Many people are familiar this symbolism so I think it will be effective. His light will have a slight hue to it. Most of the time it will be blue, but when He gets angry or annoyed it will change to red. The glow will also vary in size depending on his mood.
Location
Despite Dante's last circle, last zone of Hell where Lucifer resides actually being a frozen lake, I still went with common belief that Hell is a fiery wasteland. Stalagmites and stalactites populate the location as a cue that we are in an old, underground cavern, built over thousands of years. Magma covers most of the ground to let the viewer know that we are deep within the Earth. In the background, there are rottening corpses symbolic of those cast out of Heaven and sent to Hell. As far as color goes, a lot of red and orange hues. It is an unpleasant place, devoid of water.
I know that not everyone appreciates such pokings at religious beliefs. My goal is show the viewer that there are two sides to every story. We, as a society, are so quick to judge before we even view the evidence.