This is the final version of my entry for the Mutation Nation challenge over at Art Order. Check out the specs for the challenge here.
While brainstorming ideas for this guy, I began to build a story about the behavior and culture of these mutant humanoids. Lionfish and humans share a few traits (as far as behavior), so it wasn't too difficult to merge the two together.
The Volithar are slow moving, yet incredibly strong. They use their strength to swim through the turbulent post-apocalyptic oceans to scavenge and pillage from weaker species (like humans). They generally travel in tight knit family groups, usually no more than twenty individuals. Volithar are fiercely loyal to their own families, and will often fight or kill other creatures perceived as a threat. Because of this, vast areas of ocean may be devoid of large predators if a Volithar family has claimed it as their territory.
This species is opportunistic and will make use of any material for weapons (even their own bones and spines) and will consume just about any organic matter for food. They have an extremely high tolerance for radiation, pollution, and other toxins and will often live in areas where other creatures can't survive. A unique feature of their metabolism allows the Volithar to safely absorb toxins which are then secreted as a potent poison from glands at the base of their dorsal spines.
The hide of the Volithar is extremely thick and tough. Sharp objects are often used like needles to secure clothing to their bodies. Colorful bits of cloth and trash are added in layers to create a crude form of clothing. Although Volithar have a basic form of culture, their language is complex. Comprised of guttural rumblings as well as body posture and position of dorsal spines, Volithar can communicate audibly as well as visually over great distances.