In this world technical revolution just began, gunpowder was only invented a bit of time ago, but progress of humanity was violently interrupted by "The Arrival" event. First, a giant meteor felt from the sky, destroying all life in huge radius around it. Then, all expeditions sent to investigate it never returned back. And, finally, monsters started appearing – some very alien, creatures previously unseen on this planet, while the others seemed to be mutated humans, but everyone shared the same trait – they were praying on people. At first, it does not seemed like a large threat – but eventually humans discovered that those who were wounded by one of the monsters became infected and eventually turned into one of them.
Since gunpowder were a recent discovery, and amount of muskets and cannons were limited (not to mention that bullets barely hurt creatures that were able to regenerate their lost limbs back), melee combat was the most reliable way to fight the invaders, but also the most dangerous ones, because every wound were fatal. In great panic after millions of deaths humanity split into two parts: the biggest one built huge walls around every major city (turning them into a city-states with their own laws and culture) and hiding behind them ever since, protecting the cities with cannons and musketeer squads (who don’t have to engage In close combat), leaving rest of the planet for the monsters, and there is also a minority who chose to adapt and hide their settlements in the forests, mountains, and other remote places of the world, living a half-savage lives. The only ways of communication were zeppelins and air balloons (slow, unstable, and vulnerable to flying monster attacks), armored trains (that were easy to ambush, while tracks were hard to maintain), and small parties of reckless people who dared to travel on horses.
But like it wasn’t enough, soon people found out that more intelligent types of monsters appeared – some of them can even mimic humans they devoured, infiltrate the cities, and live there pretending to be humans, while preying at unsuspecting citizens at night. This caused new wave of panic and cities became even more separated from each other – because every person that comes from outside world has to go trough the series of tests to prove that it’s a human, everyone was afraid of their neibhoors.
This is the part where "The Order" steps in – they are group of scientists (and madmans) who did all kinds of research on the monsters, before they noticed interesting fact about their behavior: some of the human-like monsters seemed to show signs of past life instincts, and one of them were attraction to human females – often before killing them they were trying to rape them. Further research showed that the semen from these creatures do not cause females to be infected, and can even make them pregnant.
Of course, what was born in the result were far from normal human. Pregnancy period were fast – only several months, but during it mother rapidly lost weight and strength, becoming so weak that she can’t even move when it’s time to give birth. Creatures inside them are also bigger than human child and often are very deformed – so they cannot be born in normal way, instead they start eating their mothers from inside, and poor women becoming their first meal in this world.
But despite all that, creatures that are born this way still have the intellect of the human, and can be taught just like any normal human – despite growing very fast and becoming an adult in just several years, during those years they are able to learn more than normal child would learn in a decade or two. All of them have unique mutations (and potential to develop even more) that serve as great help in battle against monsters, and, what’s most important – they completely immune to their infection, that makes them the best weapon against the alien threat. So, The Order keeps abducting women to produce and train more of those creatures they call "Hunters" before releasing them to the public.
(Of course, they keep they way they are created a secret, and at some point of the game player who will discover it might face a key choice: either reveal truth to the world and destroy the reputation of The Order, turning most cities against it, but making humanity weak without Hunters, or keeping their secret, but being responsible for all the people they will sacrifice in their experiments in the future).
No Hunter is the same – each has unique set of mutations given to him upon birth, and even more that he can develop during his life.
Some of them are very human-like – for example, the only surface thing that differs them from the humans might be having dozen of eyes on their face, so simply wearing a mask (in this particular case), or somehow otherwise hiding their mutations would make most humans unable to understand that they are facing the Hunter. They will be able to complete some quests in more social ways – persuasion, maybe even seduction. But beware – opinion about you will quickly change as soon as the people will find out who you really are! Battle mutations of this kind of Hunters are usually hidden (like bone blades that can come out from the arms, small wings) and not very powerful, instead they rely on agility and brain-related mutations, that allowing them, for example, react a lot faster than everyone else (for them it looks like slowed time), restore events of the past based on clues, etc.
Other type of Hunters are more or less monstrous – huge bodies, additional hands or tentacles, monstrous faces, fur or scales – it’s very hard to hide their identity, and people are usually react to them with fear, hatred and disgust. Playing as one of them will be somehow similar to playing as Nosferatu in VTMB – you won’t get much from conversations, but you still can intimidate people, and also you are a very powerful fighter who can take the most enemies head on.
But there is one more thing about Hunters that scare people the most – all of them have to eat (or at least drink a lot of blood, I don’t know what option is better) humans to survive. They are strong enough to spent weeks without any food, but eventually they will start growing weaker if they won’t eat someone. For that reason all towns agreed to give their prisoners (usually those who are sentenced to death) as a food for the Hunters.
How it’s supposed to work gameplay wise? You have a progression limiters. To develop your character further and become stronger in combat – you must eat humans. Actually, any humans, but actions of Hunters are monitored closely, and if someone will notice you eating innocent person and report that – game will end because you will be marked as a rogue by The Order and other Hunters will track you down and kill. But nothing forbids you to live up to the horrible reputation of the Hunters are, let’s say – eat a lone traveler on the road (or anyone else, as long as it will go unnoticed), if you want to achieve power this way. But legally you will be allowed to eat only offered prisoners or people who will volunteer for that (for example, dying ones that want to help your cause – yes, not everyone in the world hate the Hunters). But there is also a trick: let’s say you arrived in town, and authorities give you a you that you can eat. But this guy claims that he is innocent, and corrupted authorities of the town just want to get rid of him this way. Is he speaking the truth, or maybe he is lying to save his life? Will you spend time to investigate, possibly provoking a conflict with authorities of the city, and gaining nothing in return, or you will just eat him anyway because you don’t care? All of that will be up to player to decide. If player will eat only those who already dying or really guilty in their crimes – he will still be able to survive, but his character would be much weaker, making the game harder to play. That’s the price of kindness – will you give up your power in order to make the right thing?
But anyway, after player will eat enough – with the help of special elixirs they will be able to develop new mutations. They work pretty much the same as augmentation systems in cyberpunk games, but instead of just replacing your external and internal parts with new you will be also able to grow additional ones – extra set of hands for more weapons, tentacle to use as a grappling hook, extra heart to resurrect in combat, wings, claws, gills – anything that fits your character’s archetype. It’s even possible that brain mutations would allow supernatural abilities like telekinesis – but I am not sure that any kind of magic would suit this world.
And there is a final detail about Hunters – all of them are seeing weird dreams, and most of them are about Living Forest – anomaly zone that spreads around the crater of the meteor that caused monster plague. People say that even trees in this forest are mutated and attacking humans that dare to enter. The anomaly zone slowly spreads, giving humans another reason to panic – but no human expedition has ever returned from this forest, and the only Hunter who did became insane and was destroyed by other Hunters. Discovering the secrets that lay in the center of Living Forest may be the end-game plot.
And here you are – half human, half monster. What side will prevail? Will you cling to your humanity, or do what’s needed to be done whatever means necessary? A lot of tough opponents will stand in your way – from smart and agile, to huge, like mountains, that forcing people to evacuate the cities if one of them chose to walk through it, destroying everything on its path. And monsters aren’t the only threat – many resourceful humans won’t mind using power of the Hunter in their own conflicts, while others (like the "Purity " organization, that’s against half-breeds) will plot against you or even try to assassinate you. What will you do? Who will you become?