The Void-Dwellers: Speciverse Entry #4
This is a species that I created for a fantasy RP, inspired by DnD, that fits so nicely with sci-fi, it gets both tags! The Void-Dwellers. Uncreative name, I know. but I at least have a story reason for it.
The Void-Dwellers: Nobody is quite sure what they are. There is rarely more than one sighting every couple years, and half of them are unproven. What are these mysterious figures? The Void-Dwellers is what mortals have called them based on what a few witnesses say the creatures said they came from: The Void between the worlds. Mortals don't know what the Dwellers call themselves, only that they are vicious and very much dangerous. But what do they look like?
Time for some real world fiction to come into play: Take a Xenomorph from the Aliens franchise. Now give it red eyes. Pure red. Like glowing red. Good. Now give them a scythe blade on the tail and cover them in strange runes and lines, all glowing red. Their carapace/skin is a dark dark green. That is the best way to describe the beasties.
They have the capability to travel between the real world and the Aether (the area between universes), but only when some very specific conditions are met. Ergo, once they come to the physical plane, they are usually trapped for centuries. And that is small fry compared to their live span. They are a predatory species, acting as little more than animals, yet they are fully capable of speech and are, in fact, very intelligent. They only seem to strive to cause as much chaos as possible, as much bloodshed as possible. They aren't invulnerable, but they have the ability to regenerate wounds relatively quickly. A lost limb can be regenerated in a couple weeks, a deep non-fatal cut in a few days. Unlike certain superheroes of our world, they have to actually heal and not in the middle of combat. They do tire eventually, but they can fight for days without nourishment. They have an extreme sensitivity to high pitched sound, to the point that long enough exposure will cause them to die of a hemorrhage. This is more than likely due to the lack of sound between the worlds, similar to that of the vacuum of space.
About their culture: Literally nothing is known for certain. One particularly talkative specimen explained their society as such: It's everyone for themselves, and alliances are formed and broken in a matter of seconds. The ones who often flee to the physical world are the weak ones that are trying to become stronger before returning to the madness. If the species ever did a mass exodus into the physical world... Who knows what could happen to a lone planet.