Whether the character is born into its halflingdom, like Twilight‘s Renesmee, or forcibly turned into it, like Underworld‘s Michael, there are certain rules that most half-human hybrids seem to follow: everyone hates them, they’re super powerful, and their conception defies the laws of biology. It’s a common trope among fantasy and sci-fi in general, but especially in paranormal romance. Let me tell you, though, it’s getting old.
Why this is bad: First off, it’s completely overused and trite. It’s been used in mythology, television, novels, music, everything. We’ve been writing – both fiction and proposed reality – about human hybrids for a long time. By now, a lot of it has been done so many times that the audience knows what to expect. The hybrid typically becomes a savior, who unites two races that have been feuding for millennia, or an angry villain bent on destruction of everything because they’re so butthurt over the discrimination they’ve faced. On top of all that, their powers are ridiculous and they almost never have any drawbacks. Typically, being a halfbreed is pretty rad (except for the species-ism, of course). We know what to expect, we know what the hybrid is probably going to do, and so we don’t put much stake into them.
How you can fix it: One of the big positives to having halfbreeds is that they’re typically there to emphasize the humanity of one species and the danger of another. They have the ability to make the audience connect better to the non-human species and become more involved in the story. But you know what? They can still do that without the ridiculous gains in power. It’s highly unlikely that your character is going to get away with no physical or biological repercussions from being a halfling. Make your half-vampires burn in the sunlight. Make your half-demons sensitive to holy water. Whatever you’ve got to do, make sure you give these characters some downsides, because the only thing that typically holds people back from making more of them is the social stigma. “Oh, you mean our kids could be super strong, super fast, but silver doesn’t hurt them? Why shouldn’t we make more or those again?” If this quote can fit into your story, maybe take some time to think over why and how you’re using this trope and if you can insert some real downsides. You could even subvert it by making the majority of characters not care. If you’re really excited about the concept of halflings, maybe have some organization that is either encouraging or forcing people to have them.
Bottom Line: Halflings aren’t an excuse to make a demon with no weaknesses. Give this new species its own flaws, its own ways of dying that link back to its heritage, and reasons to care. We can relate to them, and we’ll be able to relate to them even better if they have weaknesses.