Sometimes the right prompt comes out of nowhere and all you can do is write it. Being a fan of movies like Underworld and anything related, I felt compelled to write this AU. Also, the lack of urban fantasy AUs was another big push for me to write this. To anyone that's been reading my other works, the two ongoing stories about Star Wars, don't worry, they're not abandoned. Just on hiatus.

Thanks to Alex from castlefanfics on Tumblr for the beta reading, God knows I need it and to alyssinmymind for the artwork. I owe you a lot.


Prologue

For centuries they had been only material for legends and folk tales. Superstition fed myths about the immortal creatures of the night, tales to scare children and keep them in line with the threat of the boogeyman that would come and take them at night if they didn't behave.

Witches flying on broomsticks cursing people, fairies helping them. Corpses returning from their graves, brainless and craving human flesh, troubled spirits of the dead, haunting the living with their presence, the dangerous werewolves hunting during the night o the full moon, in the woods, howling and banqueting on herds and the occasional traveler. The fascinating and elegant vampires, feeding on the blood of the living, the most dangerous of all for their similarity with their helpless victims. With the discoveries of the ancient Egypt tombs and the mummies, another kind of monster became famous, ancient curses falling upon those who dared to disturb their millennial sleep.

Names changed with the culture and the language, even their characteristics weren't uniform, the descriptions were diversified through the years, but in every culture of the world there were legends that told the stories of the immortals. These stories so famous that with years, and some refinements and with the help of history and the genius minds of writers, they became the horror stories that are known today. John Polidori helped shape the figure of the vampire, which inspired Bram Stoker to create Count Dracula, based on the story of bloody Vlad The Impaler, an historical figure from Romania. Gervase Of Tilbury was credited for one of the first descriptions of lycanthropes and old women with expertise in healing with herbs and flowers were described as witches by the superstitious crowds, their hate fueled by religious ignorance. Fairies became famous when authors such as the Grimm Brothers and their colleagues created the traditional fairy tales that Walt Disney transposed on the silver screen. Mary Shelley and her Creature gave birth to the application of science in horror literature.

By the time the twentieth century had come, these creatures, once feared and a cause of distress among the populations all around the world, became a source of entertainment. Authors and actors becoming famous for their portrayal of monsters and various folk creatures. Most of the movies in the early years of cinema featured these creatures, with zombies, vampires and werewolves becoming essentially a cultural phenomenon throughout the world. They lost their scary characteristics and were seen more as romanticized figures that once were used to keep kids in line. People dressed like them for Halloween, Hollywood made billions with films about what once used to intimidate people.

Immortals had become a business.

And unbeknownst to humans, that business helped the real immortals thrive and integrate with society. Despite being relegated to creatures that had spawned the legends that had been told for centuries, werewolves and vampires did actually exist. Hidden from the world, they had lived for thousands of years along with humans, trying not to be seen.

And they had managed to remain hidden, to keep their existence tied to legends and ancient lore that no one believed anymore. Until the mid-seventies, with the advancement of medicine, new diagnostic tests were created and those tests caught diseases better and faster than before, but they also foundsomething else. There were abnormalities in some specimens' blood, differences that made their blood thicker, in a sense, with increased cellular functionality, faster mitosis, better oxygen transportation and an extremely efficient immune system. Upon lab testing, those samples of blood were completely immune to every disease, be it a virus or bacteria, as well as immune to every type of poison.

They performed test after test, until someone tried to expose some samples to a powerful UV light source, in reaction to which a part of the samples deteriorated. If exposure was long enough, deterioration was beyond repair. Thinking about a new form of porphyria, the tests went on until further research and the advancement in DNA technology brought an incredible discovery. The DNA of some people, a very small community spread throughout the US – and possibly the world - according to the CDC, carried an unknown pool of genes that had never been observed since the invention of DNA testing. At first it was thought to be a mutation brought on by the still-going evolution of the species, however when some of the owners of those genes were questioned about any possible difference between them and the standard human being the incredible truth had been revealed when a scared vampire teenager pressured by the CDC investigators, told them the truth about his nature.

That's how immortals were discovered.

The news spread all over the world faster than light, leaving humanity baffled and unsure of what to do. According to the legends, immortals were dangerous killing machines, feeding on human blood and flesh to survive, sleeping in coffins or hunting in packs at night. Finding out that, after all, they weren't just stories designed to tingle our senses and provide us thrills during slumber parties, was a shock for everyone.

In some areas of the world witch-hunts broke out and immortals were driven out and blamed for things that were completely unrelated to them. Fear and hate were the first emotions that spread, along with shock. Some were killed, because even if they were apparently not able to age, there were some weapons that could kill them all too well.

But with time, opinion on their existence became different, the change was slow but it happened and new laws were written to include them in society. Throughout the nineties, the world slowly became, year by year, more immortal friendly. Some people were still wary of them, there were some religious groups that advocated for their death, not too different for those hate groups that detested homosexuality, although the situation was a lot different. Hate groups against immortals were scared of their power, so usually kept away from them and attacked using only words, hate groups against homosexuals didn't care and often acted violently against them. In a twisted way, immortals had it easier.

At least werewolves did.

Lycanthropes could hide in a crowd more easily, they didn't have specific signs of their species on their body, by the time they reached adulthood most had learned how to control their transformation and weren't a slave of their mood anymore. Legends said they changed only during the full moon, but it wasn't true: a werewolf changed into his or her lycanthropic shape when in a foul mood, when in pressing need and when scared, or at will, when they learned how to do it. They didn't have special marks, or any visible difference between them and a normal human being.

And there was nothing supernatural about it, they weren't bitten by cursed wolves under the full moon, werewolves were a different form of humans. They weren't part of the same species, they weren't homo sapiens sapiens. They had been dubbed homo lupus sapiens by scientists, but they had nothing in common with wolves on a biologic point of view. They had a similar morphology when they changed, although they retained their two-legged posture and their features morphed to a more beast-like appearance, with a slightly elongated muzzle containing sharp teeth, and their nails grew to sharp claws. Their musculoskeletal structure changed, they grew bigger, more imposing than their human form, but their basic anatomy didn't change drastically. Some of them grew longer and thicker body hair in their transformation, but it looked nothing like wolf fur: it was normal human body hair, just thicker and longer. There were smooth werewolves, although they were extremely rare. Their senses were also heightened, but that happened even when they were in their normal state. Biologist, geneticists and anthropologists all over the world were working to locate the origin of the genetic mutation that caused lycanthropy. Most agreed on considering it a way nature had come up with to protect humans living in harsh, cold territories where they could be easy prey for large animals. Werewolves normally had a higher body temperature and had a naturally buffed physique that made them look like they worked out even if they were the greatest couch potatoes in the world. No one would notice this and that gave them an edge against predators, when the species had evolved. Or partially evolved, as an expert in evolution hypothesized. They looked like normal human beings with superhuman strength and more chances of survival in the case of a zombie apocalypse.

Vampires though, they had it much harder.

After thorough examinations, it was found that vampirism was indeed a new, yet undiscovered form of porphyria, or at least a similar disease. The most accredited theory said it may have spawned from erythropoietic porphyria, the most extreme form of porphyria, and evolved in its own way when it found a tougher than usual group of humans that resisted the disease. It progressed to become an integral part of their genetic code, thus made vampirism a genetic mutation as well, that caused extreme sensitivity to sunlight, extreme anemia that required the consumption of blood, or in modern times, iron supplements and a specific diet, and the trademark sharp canines that allowed them to consume raw meat, a perfect source of iron, without an itch. And, just as werewolves, vampires had acquired some peculiar abilities that made her superior to humans: improved senses, enhanced strength, they required less sleep than the norm and they were naturally more perceiving than usual. Some people thought they were able to read the minds of other people, while in reality, their intuition was just sharper than theirs. Obviously they didn't fly or turn into bats, those parts were just plain bullshit, but the mind reading was nearly true, coupled with the fact that they could charm away nearly everyone they met, they had their perks. Their need to hide and keep out of the sun had turned those affected by vampirism into the perfect investigator, an evolutionary trait that made them able to sneak out of even the direst situation without a scratch, only by talking their way out of it.

Again, biology had an explanation for their condition.

What seemed peculiar was the rate those conditions spread: being DNA-related conditions, one would think normal genetics would apply, but it turned out that the pool of genes that determined both vampirism and lycanthropy were recessive genes. Above all, vampirism developed only if the extremely rare form of porphyria linked to the condition met those specific genes that made it turn into vampire-related porphyria, as vampirism was usually called by scientists. Same went for lycanthropy: the mutation was hereditary, but even if two werewolves had a child there was a chance he or she would be a normal human being. Mixed couples had equal possibilities: a werewolf and a human could have a perfectly healthy human being that would grow, age and get sick at a normal rate, a fully developed werewolf or a human that expressed some characteristics of lycanthropy, like the better working immune system or the exceptional, innate strength, but no other visible characteristics. Immortals could be born by a human couple too: if one parent had the recessive pool of genes in his or her genetic traits that weren't showing for any reason and the other brought on the part that made the DNA mutate into vampiric or lycanthropic DNA, an immortal child could be born. Still rare, but not exceptional.

But scientist were baffled most by their technical immortality. Their cells divided and replicated impossibly fast, according to traditional science, a feat that allowed them to cure themselves faster and survive gruesome wounds that would kill a normal human being instantly. Their immune system killed any foreign intruder in their body and vaccines looked obsolete when compared to their natural immunity. They aged, but the rate was much, much slower: a century old immortal looked more like a twenty-something human. And they kept that appearance for ages. If an immortal looked like a sixty years old human or older, you could bet that his or her age would span across millennia. Those were rare, but some of them still existed and simply pretended to be normal aging humans.

According to some, they were the next step in human evolution. Others considered them the devil spawn. Most of the human population didn't care as long as they didn't kill anyone. Thus, the world changed. So did the law.

Anti-vampiric mobbing was declared illegal and firing a vampire or a werewolf based on their species was punishable by law. Vampire safe-zones were established and lasted from ninety minutes before sundown to one hour after sunrise, which meant it seasonally changed. During that time frame UV radiations were at their lowest and it was safe for them to go outside. Most vampires took night jobs or night shift even before the revolution so very little changed for them anyway, but for those who had demanding jobs, specific windowpanes that filtered all the UV radiation while letting sunlight in were created for both houses and commercial buildings, which made their lives a lot easier than in the past.

Of course, there were issues. Laws were made to be broken, so some companies instated internal rules and policies that wouldn't allow immortals to be hired. Some companies were openly anti-immortals and they weren't silent about it. Others were more inclined to accept them, public administration had to maintain a neutral ground and slowly, by 2002, nearly twenty years after the discovery of their existence, the first few immortals were seen working actively in public places. In 2003, a youn immortal, freshly graduated from NYU, became the first of the newly discovered species in to finish the NYPD academy.

In 2008, Katherine Beckett was promoted to detective and moved from vice to homicide. She was the youngest woman in the police department to be promoted to detective.

She was also the first vampire.