In my universe, the source of Terra’s vampire legends are a species called Keratians. Their home is Toros, a large world that orbits a bright red dwarf. The gravity there is relatively intense. We would weigh five times greater were we to step onto Toros. That may not seem like much, but consider that on Uranus, you would weigh a little over eight times what you do now.
Keratians are humanoids and can easily be modified to appear human, provided they are not examined too closely. Their morphology is anything but, however. True to vampire lore, they do have a liquid diet. But their food comes from excess blood milked from their symbiotic herd of rodan. The thought of consuming blood from other creatures is revolting to them. In return, they defend the rodan against the apex predator of Toros, simply called the wraith. So, rather than the fearsome, ravenous, bloodthirsty creatures of the night that have an insatiable appetite and mindlessly kill and consume, they are meek shepherds by nature.
However, meek isn’t weak. The wraith is a monstrous creature deserving of our nightmares that truly gives the Keratian a challenge. Their spines are made of a meta-material that can penetrate nearly anything the wraith can push them into with very little resistance. They are exceedingly fast and determined predators.
As a result of the evolutionary arms race, the Keratian has developed a skin that is resistant to the spines to a varying degree. Because of that, their skin can withstand any projectile that Earth can throw at it. But it’s not 100%. Wraiths can still impale a Keratian. To give them an edge, Keratians have also developed the ability to accelerate and decelerate exceedingly rapidly and travel at near orbital velocities, using a biological access to sub-quantum physics. The effect is akin to squeezing a dried bean in between your thumb and forefinger until it pops out and flies across the room. They draw on the warping energy that planetary masses have on space around it. Between that and their strength, robustness and intelligence, the Keratian has served as an adequate defender of their rodan herds.
Ironically, in modern times, the Keratian have also adopted the role of conservationist, actually preserving the wraith against extinction.
Their blood is titanium based, rather than Terran’s iron based blood. It sounds exotic, but it doesn’t give them any special abilities anymore than the copper based blood of horseshoe crabs. It’s just another oxide. The result is simply a white blood, and a resulting white complexion. This has served to feed Terran vampire lore pretty well. Additionally, their metabolism is exceedingly efficient. They don’t produce waste heat. While within their bodies they would be warm, their skin would feel as cool and hard as marble.
One special characteristic I have applied to these creatures is what I call a second skin. It exists mainly in quantum space and manifests as a vapor that solidifies into a loose, black cloak. At speed, it would contract tightly around their skin, creating an interference layer around them that smooths the slipstream and prevents friction heating. This second skin forms over any other clothing the Keratian may be wearing. Interestingly, inspiration for that comes from various creatures on Earth that produce a defensive layer, like the parrot fish when it sleeps at night.
Because of their efficient metabolism, Keratians are extremely long lived. The oldest survived for over fifteen thousand years. Lohet, commander of the Chaser team that was sent to Earth, was a little over four thousand years old, while his main boss, Orin, was ten thousand years old. There are few species of the Cooperative that live longer, such as the Librarians and Faeries.
In the War, Keratians served as front-line soldiers against the golems. They were the only species able to go toe to toe with a golem, excepting for Trolls, perhaps. But unlike Trolls, Keratians proved ideal because of their strong defender instincts.
A few caveats. While they can travel at high speeds, they find it very hard to carry less robust species at those speeds without harming them. Even Migalo, a tough Camdyn who at the time was in armor, nearly suffered whiplash when Lohet grabbed him and accelerated across an enemy compound to get past a security door before it closed. Also, even at high speeds, they are still subject to regular physics. They cannot change direction rapidly because an object at speed wants to keep going straight.
An interesting note of interest. Wraith spines are used as the only physical weapon able to harm a deviant because of it’s resistance to heat and its ability to penetrate most materials. What’s a deviant? Read my books and you’ll find out.