Gray skin and red eyes is a common look for Dark Elves, and I have a similar race in my own world. But what would physically cause such an appearance?
- Must not be the result of severe life-altering disease or require extreme deviation from normal human biology.
- Must be true gray, not purple or dark brown or something.
- Should be permanent and inheritable, not just a temporary state or tattoos.
- Should not cause bizarre texture or scaly/rocky look. The gray people should be potentially pretty, because otherwise they'd be called goblins, not elves.
I've had a thought that my gray people are gray because, like an elephant or dolphin, their skin is thicker and so fewer blood vessels show through. EDIT: I've now been informed that elephants and rhinos have gray pigmentation. I wasn't aware such things existed. Would that cause them to look excessively wrinkly or chubby or sandy though?
Another possible explanation is that they ingest something that makes their skin grey, much like argyria. However, that particular condition actually makes the skin more shiny purple than gray. I'm not aware of a condition that makes you gray like Dark Elves, that doesn't also kill you.
So these guys don't really look like the glamorous but grim dark elves that we want in fantasy, but it's halfway there. I know how to satisfy the hard requirements, but not the soft ones.
I was originally going to also ask about red-to-yellow eyes, but they're covering that over in How would red eyes occur in a human (without underlying medical conditions)?