Creating Fictional Races in Writing
Creating fictional races is very difficult. On one hand, you want to show off your imagination, but on the other hand, you want to follow simple rules.
For those who may disagree, understand that I’m breaking this into two areas to make sure the concepts of Science Fiction are different than Fantasy. You may ask why, and by all means do so. In Science Fiction we are tied to constraints that, though nature may have a humours side (duck billed platypus), there are rules one must abide by. An alien head with no mouth does not make sense, especially if you put the mouths on their hands. I guess cleaning up is a real crappy job for them. But a magical being with eyes on the ends of their fingers makes perfect sense in the realm of make believe.
Science Fiction and Nature
In the realm of Science Fiction you must remember, everything needs to work. The being with a mouth on its hand would have a very hard time eating for the oesophagus will need to propel food up hill to get into the stomach, making eating a very difficult task. The length of said oesophagus then needs to be as long as the arm, thus making it difficult. Nature usually takes the route of least resistance.
Think of an alien. No really, think of one. Now, imagine how it evolved. Why are things the way they are? Does it lay eggs or suffer through live birth? Hair, feathers, stubble, or a mixture? And if so, why? One, two, four or more eyes? What would cause such?
I look back at the wonderful works of fiction I read in the past and see the logic behind most of the species. Using logic will make your Science Fiction work more impressive to a reader. But not using such will cause someone to shake their head and put the book down.
Fantasy and Horror
When creating fictional races in Fantasy and Horror, throw all the rules away. Especially in horror. If something looks strange and fantastical it should be used. Fantasy is just that, fantasy. Beyond the realm of possibility. Now a creature can have eyes in the palm of its hands or skin peeled away with an open trachea exposing the air way to dust and bacteria. It is fantasy and horror, the flights of imagination. It doesn’t need to make sense. So having someone amputate their arms and replace them with swords because they fight in an arena is not unheard of (The 300 – The Headsman) or no eyes near the brain (Pan’s Labyrinth). Think of Pinhead in the Hellraiser series by Clive Barker or a Mind Flayer of D&D. These creatures could not exist in the real world.
So, as a writer, what genre you pick will be the main driving force behind what you keep in mind when creating a fictional race. It can be logic and nature or the worse nightmare imaginable. Strange and abstract or very similar to life as we know it on Earth.
It is up to you to decide.