Give us something to stare at.
As a writer of epic fantasy and urban fantasy, I’ve stumbled across my fair share when it comes to reading the stuff. One thing I have consistently noticed is that few books in these genres are populated by only species found on our Earth. Whether it’s humans with magic or completely different creatures, the other worlds are crawling with “them.” And, why shouldn’t they be? It’s fantasy after all.
The trick is then this. Where do they come from, and why do they make sense? Answers: they came from somewhere and they make sense because the authors make them do so. Annoyed at me yet? I speak the truth. Whether they came from folk lore, genetic splicing of previously used creatures, or the author’s imagination—all non-Earth creatures originated somewhere. Similarly, they work because whoever invented them sat down and worked out a way for them to exist in the world of the book. Sounds simple, right? Wrong. I will attest to this. My half dryad took a while to solidify.
So, what do you—the aspiring fantasy author—do? Well, after the obvious steps (selecting a setting, the general makeup of the world, and the plot—in case of species specific plot issues) you decide on species for said book. If you grew up on Dungeons and Dragons like I did, you have books of monsters and creatures at your disposal. If you didn’t, all hope is not lost. A Google search for any creature will bring up a wealth of options for background on said creature.
Don’t know the name of the creature you want or don’t even know enough creatures to search by name? Wikipedia offers a comprehensive A-Z List of Legendary Creatures. Click on the letter you want and then click on the creature to be brought to a detailed article about that creature. See, that wasn’t so bad. Heck, even if you are a creatures junky, a search of what’s out there can’t hurt.
Now the tricky part—did you find almost the creature you’re looking for? Well, as almost only counts in horseshoes and hand grenades, this is where the genetic splicing takes place. How many modern titles feature creatures that are nothing like or just slightly different from the ones in legends? Make your creature into what you want, but be careful. Do you reading and see how far the limits of a creature can be pushed before you should rename it. For example—a vampire who doesn’t suck the life of humans in some way would no longer be a vampire. However, if you wanted to have your vampire suck out happiness or, in Jim Butcher’s “The Drezden Files” case, feed off of human lust—that’s okay. In my personal opinion, though, avoid vampires as your main creature. They seem to be getting a bit overdone.
Now, you’ve selected your creature(s). Alter them as you wish and then plug them into your world. If they don’t work, remake them or the world. If that still doesn’t work, try a new creature, but DO NOT GIVE UP!!! There’s a creature out there for you. (That sounds like a bad dating commercial.)