Supernatural beings... Writing about them.

[black_hawk_sam]

I am completely stuck with a couple points on different supernatural beings. Namely, a demon... but really any type of magical/sci fi being...

any suggestions or tips on how to make a realistic unreal character?

[jeno]

Give the thing motivations. What does it want and why does it want it? How does it go about getting it?

If it's a flesh eating monster, why does it eat flesh? Does it need it to survive? Is it just that malicious? How does it attack it's victims? Does it need claws?

Is it a creature that makes bargains with people? What does it get out of the bargains? How does it go about making deals? How does it contact people? What appearance does it need to facilitate his goals? Etc.

Are your demons comedic, or are they scary? Are they major antagonists or are they just mooks?

Take a look at how other authors portrayed demons. Specifically, authors OTHER than Jim Butcher, since I'm assuming you've already read the DF/CA. See what strikes your fancy.

And then, in the immortal words of Tim Gunn - make it work.

[Guardian 452]

Beyond motivations, ask yourself about the creatures' morals...at least as far as they relate to the story.

For example, will it take a life if that individual (regardless of species) gets between it and its goal?  Are there specific races it doesn't recognize as important?  For example, would it kill a human that stops it, but not an animal?

It's sort-of like writing an alien.  Think about the environment it usually exists in, and what rules it's developed as a result.  The point here is don't just make it a redressed human.

[Nickeris86]

look at some of the ancient lore out there as well there are thousands and thousands of demons and monsters that already exist and they make good base material for your own creations. Take the Alp for example (and this is just off the top of my head and is not part of any of my works) they are mean little German demons kinda like a incubus, they sit on your chest and get heavier and heavier until you can't breath, while simultaneously entering your dreams and turning them into nightmares. you can get rid of them with lemons or by stealing their magic hat, no i am not kidding.

now you could take that concept and tweak it and make it your own, like have them steal dreams or memories from sleeping victomes and instead of wearing magical hats they can literally put their fingers into your dreams and steal them. and they could have a fear of flowers instead of yellow fruit.

[Snowleopard]

I think it was Patricia Briggs that did the Hobbs Bargain where the story is told from, I believe, a small no-account
goblin's point of view.  You see how the character views normal humans and other Fantasy creatures.
Or there is - The Screwtape Files - I believe they're called - about a demon trying to get back to where it belongs and being
really unhappy in our world.  I think.

I would think you could pick a couple of traits that the being shares with humans but how they differ from us.
Or go the entirely alien to our point of view route.
The Predators from Predator.  They were ferocious hunters but they had certain rules that gave them a touch of
humanity.  Not harming non fighters, not harming the innocent (an unborn fetus), and respecting a winner even if
one of them died.

[Nickeris86]

Insects are great for making a creature completely alien, you don't have to make them look like a bug but the way they think, or lack of thought just pure instinct. No fear, no remorse, the only things a person could relate to are the need to feed.