Once, you were a part of something bigger. You were an angel of the God-Machine, a thinking machine yourself, with purpose and the means to fulfill it. But for whatever reason, you Fell, casting off your creator in order to climb into the shell of humanity - you became one of the Unchained, a machine wearing human flesh, a demon.
And that wearing human flesh bit is more literal than you would have thought. Emotions have bubbled up in your mind where there were none before; the body that was once a mere disguise is now a true vessel, needing food, shelter, and rest. In a frantic dive to safety among humans, demons become something much closer to human than they ever were before - and for many, it is a difficult transition. No matter how much they might seem to be, demons aren't human, and when it comes to pretending to be mortal, there is a learning curve.
On the other hand, they are also no longer angels. Suddenly gaining free will is overwhelming for many, especially when it comes at the cost of the comforts of purpose and connection. Demons have cut themselves free of the Machine, but there is no guidebook for where they're going now, and that's a frightening prospect. And wherever they go, their old fellows seek to return them to the fold - usually as part of a scrap heap. The God-Machine has no desire for servants and parts that don't do their jobs; easier to just eliminate them before they cause problems than to try to fix them.
Demons are grouped by Incarnation (a grouping based on their purpose in the machine before they Fell) and Agenda (what their goals are now that they have the freedom to make choices). Their society, such as it is, is a strange mix of mutual support and suspicion - no one understands demons like other demons, after all, and no one is in a better position to backstab them. That's the problem with being a society of perfect liars.
What is the God-Machine? While demons are in a far better position to find the answer to this than most, they don't really know, either, any more than a finger understands the whole of the person it's a part of. Where it came from, what it ultimately wants - debates in code on secret servers run in circles on these questions. Demons just know that it is.
Destroyers: When judgement comes, someone needs to dish it out. Destroyer angels are that someone - whether it's taking out out-dated Infrastructure, hunting down demons, or taking care of a pack of mortals who've gotten a little too nosy, they're what the God-Machine relies on to make things into corpses and ash. Not all of this destruction is so violent (destroying someone's reputation is just as much under their purview), but that's the reputation Destroyers have. They're likely to fall either to a moment of mercy for a target or, conversely, to enjoying their jobs too much and refusing to stop when the job is done.
Guardians: Everyone's heard of guardian angels, right? These Unchained were once protectors of whatever the God-Machine wanted protected - sure, sometimes that's cute orphan children, but more usually it's specific pieces of Infrastructure or the site of an occult matrix. It is true, however, that those doing the orphan-guarding are more likely than their Infrastructure-guarding peers to Fall, as they get attached to what they're supposed to be guarding. Failure is another major reason for their Falls.
Messengers: Someone needs to take God's word to the people; this isn't any different when the god in question is the God-Machine. Messengers are the angels that specialize in interacting with humanity (and, occasionally, other creatures) in order to bring them in line with the God-Machine's plans. If there's a cult of the Machine around, chances are there's a Messenger at the head of it. They are the most likely to Fall due to attachments to their Covers and human identities, and are generally preoccupied with humans in a way that other Incarnations aren't.
Psychopomps: Someone has to build Infrastructure in order for everything else to work. Psychopomps are those angels in charge of making that happen, the grease between the gears that keeps everything running smoothly. Until they aren't. Psychopomps are often the demons who know the most about Infrastructure, both to destroy it and to subvert it for their own purposes. Psychopomps often Fall over 'creative differences' with their orders; an angel who thinks they can build it better, or who considers striking out on their own, will soon find themselves on the road to hell.
Analysts: The Eyes of the God-Machine have few interactions with other Angels, and thus there are many demons who do not even know of their existence. Though probably the most common of angels, most Analysts are given missions that do not give them much cause to Fall. Watching and reporting back doesn't leave a lot of room for the interactions that give most other Incarnations a reason for Falling. Curiosity and wanting to understand the data they've gathered is one Fall point for them.
Inquisitors: Control of information is your best weapon against the God-Machine. If it doesn't know where you are, it can't find you. If you know more about it than it thinks you do, you're better prepared to avoid it. Or fight it, if it comes down to that, but Inquisitors would rather avoid that entirely. Nicknamed Paranoids by other Agendas, they think that knowledge is not only the best protection from the God-Machine, but the best protection from their fellow demons. Expect an Inquisitor to have back-up plans for their back-up plans - and for them to be entirely willing to abandon the whole thing and take on a new Cover when things go south. What their enemies don't know can't be used against them.
Integrators: You were once a part of the Machine. Somehow, you Fell - you made a mistake, had a moment of weakness. Now you want to go back. Integrators miss being a part of the machine of some larger purpose, in a way that members of other Agendas don't. This makes them almost universally distrusted, even by demonic standards. Most Integrators aren't so foolish as to just walk up and ask to be taken back, though - they're all too aware that ends in them becoming scrap metal. They have to prove themselves worthy of rejoining the folk - something that often results in them serving other demons to their former master on a platter. Not all Integrators think this way, though - other seek to change the God-Machine into something they find more tolerable before they rejoin it.
Saboteurs: The Machine needs to be stopped, and Saboteurs are the demons with an eye towards making that happen. Whether it comes from a hatred of their former master or simply a desire to live in a world where they aren't trying to look over both shoulders at once, they are willing to risk life and limb against Infrastructure - nevermind the less important elements of Cover and contacts. Saboteurs are known for burning through Cover more often than the other Agendas, and aren't above getting others involved to further their goals. Risky as it is, they tend to gather where there are large amounts of Infrastructure, waiting and studying it for the best opportunity to break it, or die trying. Better to go up in a blaze of glory than to get snuffed out quietly.
Tempters: There's living among humans, and then there's living among humans. Tempters are the demons who have decided that mortal life is actually pretty great; many of them are those who Fell because of humans in the first place. They embrace their newfound free will and emotional capacity with gusto. While they'll turn and run the same as any other demon when faced with hunting angels, the Tempters feel the loss of their well-built Cover lives most keenly. Whether it's money, social power, or a picket fence with 2.5 children and a dog, Tempters not only have their eyes on the prize - they already have a plan in motion to get it.
Embeds: The standard variety powers of demons, Embeds work using laws coded into reality by the God-Machine that only angels and their Fallen counterparts have access to. These are usually small powers, such as becoming less noticeable simply because you're in a crowd, control over a coin flip, or always having the right kind of ID to be allowed into a restricted area. Most demons have a fairly extensive group of Embeds to fall back on, and while they can't create these abilities from practice the way other supernaturals might be able to, they can remember things they used while a part of the Machine over time.
Exploits: If Embeds are using the God-Machine's laws for their intended purpose (just without permission), then Exploits are hacking in to take control of the car. Rather than summoning convenient ID, a demon might be able to summon any object they can imagine into the trunk of their car. Rather than making a good impression on a single person, an Exploit can make everyone in the room hate one person for no apparent reason.
Perfect recall: Being that they are actually machines, not organic life, all demons have perfect recall of everything they've seen and experienced. Vision, touch, taste, the sense in question doesn't matter - any time they so desire, a demon can revisit the experience as though it were new. Of course, this comes with the downside of not being able to forget the less pleasant parts of life, too.
Demonic form: Underneath their human Covers, the true forms of demons come in a wide array of shapes, mostly based upon the forms they had as angels. Taking these forms is risky, but they are much more powerful than mortal flesh. Sometimes, demons can manifest specific traits from these forms - making their hands into sharp metal claws, growing white-hot metal wings, causing humans to quiver in awe with a single sharp look. Most of the time, however, the demonic form rests in a quantum space, where it both does and doesn't occupy the same space as the human one, and there it is safe from detection by the God-Machine or anything else.
Cover: A demon's Cover is the human life they live to keep out of God-Machine notice. It isn't simply a human skin; it's a place in the world, having your name signed to the lease of an apartment, the girl you dated in high school, what you ate for supper last night. More than simply being human, Cover is playing the role of whatever life you're leading. A demon whose Cover is an art student can't pick up a military-grade gun and go off shooting angels; that doesn't make sense in the context of the identity they're supposed to have. While few demons have the moral scruples that a genuine human would, the requirements of their Covers keep them from acting too wildly.
Liar's Tongue: As part of their Covers not truly being part of themselves, demons are master liars. Even supernatural means can't tell what a demon is truly thinking, because of this disassociation with their real selves. This even goes as far as their emotional responses; no matter how afraid they are, a demon's heart rate doesn't rise unless they choose it to, and every smile is carefully chosen. It's a perfect deception that will even, most of the time, fool things that can sense them as being supernatural at all. In addition, demons can speak any language that has a living native speaker.
Pacts: A demon's Cover doesn't start out great; they have to build it into the world to help it pass muster. One of the ways they can do this is through pacts, where a human trades some aspect of their life in exchange for some benefit from the demon (usually the demon using their powers for some material benefit). The most powerful of these is the soul pact, where the human signs over their soul, thereby enabling the demon to, at a later date, come and take over their lives as a new Cover. No one tells the human what they're agreeing to, of course.
Most of the weaknesses of demons come from the constant risk of attracting the God-Machine's attention. In addition to the weaknesses detailed here, a number of their other abilities - especially taking demonic form - come with the risk of attracting angelic notice. And, for the most part, a demon that gets noticed and can't lose themselves quickly again within the crowd doesn't have much longer to live.
Glitches: Tamper with the code of reality, and eventually something isn't going to work right. While glitches in demons are thought to be the result of being away from the God-Machine's maintenance routines, they also manifest in stigmatics. They typically manifest as changed physical traits (called brands; examples include strange scars or unnatural hair colors all the way to only being able to consume battery acid), odd behaviors (called tells, ranging from having to knock three times on any door passed through to compulsions to stop and count fallen leaves), and environmental effects (called emanations, which affect only the most powerful of demons; examples include odd smells and sudden chills all the way to things like the demon constantly appearing farther away than they are or lights flickering every time they speak). Some glitches fade over time, but others are permanent, including the minor ones affecting stigmatics.
Smaller power base: Most demons, even on their best days, have a far smaller amount of power than they did as angels. While it's plenty to take care of threats from mortal sources, demons operate undercover for a reason. In a straight fight, unless a demon burns one of their Covers as fuel (an action known as "Going Loud"), they will always be weaker than even weak angels. Against a powerful hunter angel, backed by the might of the God-Machine? Better to run and live another day.
Aether: The most powerful abilities of demons require fuel - specifically, aether, which is a waste product produced by the God-Machine. Thus, it's risky for demons to venture too far away from Infrastructure; they might be better able to hide out in rural places where there's fewer angels to discover them, but if they are discovered out there, they have far less potential power to defend themselves. Of course, even when there's suitable Infrastructure to be found, there's the matter of getting close enough to use it...
Sometimes by accident, sometimes by design, humans come in contact with Infrastructure. This brush with the God-Machine's power leaves scars - days to weeks of horrifying visions, followed by the addition of a small supernatural tell referred to as a "brand." Like the glitches developed by demons, brands take many forms, from semi-literal glowing tattoos to leaving footprints of ash wherever they walk.
What all stigmatics have in common, however, is that they can see Infrastructure the same way that agents of the God-Machine (current and former) can - and that those same agents tend to seek them out as a result. Both angels and demons favor stigmatics for positions in cults and as bait for their counterparts, and both are very difficult to say no to for any length of time.
Humans aren't the only ones who accidentally trod upon the God-Machine's grounds. Animals who have such encounters are called cryptids, and they come in an even wider variety than their human counterparts, bodies and minds mutating to develop strange new powers. Most commonly, however, they develop a sense for Aether that rivals a demon's, and many cryptids consume the substance - good for both angels and demons seeking to track down such sources for whatever purpose.
In keeping with their attempts to blend in to humanity, the Unchained are some of the few supernaturals in the world that can have biological children in the same way as the humans surrounding them. These children gain some of the powers of their demonic parent - and if both parents are demons, the affect is amplified.
Most of these children inherit the ability to use Embeds, the lesser abilities of demons that interact with the code of reality. Sometimes those a generation or more removed from a demonic parent will also develop these abilities, either as children or at a time when they should have simply become stigmatics. Indeed, those children with the ability to use such powers have all the marks of a stigmatic, including a small, permanent glitch.
More rare is the child of two demons, who has even more mastery over such abilities, and an ability unique to them; the ability to see through the Cover of their parents. To the child of two demons, Mom is a statue of mechanical ice and Dad is a suit of oil-covered armor, and that's just the way it is. With time and effort, they can learn to use to see through the Covers of other demons as well, making them incredibly valuable to both demons and the God-Machine.
You have to start from on high in order to Fall. Angels are the beginning of the story, the faithful servants of the God-Machine, closer to it in every way than their Fallen siblings. Not only are they connected to it in a constant stream of data, but they are more like it, without the emotional reactions that bring demons closer to humanity. Their only consideration is their missions; they don't have a need for free will or individual aims, and it doesn't even occur to them to consider wanting it.
This does not mean that angels are not individuals - both physically and in personality, angels are built for their tasks, and those tasks vary widely. It also doesn't mean that they can't be allies, of the God-Machine's mission for them happened to align with another party's objective. It is wise to be wary of such arrangements, however, because the angel won't feel at all bad (won't even be capable of feeling bad) for betraying demons (or any other allies) to their master once the mission is over. Indeed, an individual angel is wiped clean of any memories and damage between missions, though fragments sometimes remain.
Angelic abilities are similar to those of demons, but they require Essence to use their abilities, and create Aether in doing so - the latter is a boon to demons, who can sometimes detect angels by sensing such Aether. They have Covers, but they are not Covers in the same way that demons possess them; an angelic Cover really is more like a human skin, and doesn't require the physical care or social connections that a demon's does in order to be 'real.'When not in their Covers, angels often spend their time in Twilight, the realm of spirits and ghosts, unrestrained by physical impediments. Some angels have no Covers at all and exist only in this state; this is especially true of Analysts and Guardians.
An angel that begins to experience emotions, question its existence, or even care particularly much about things outside of its mission objective is an angel on the edge of Falling. The moment of the Fall is always distinct, as their connection to the God-Machine suddenly goes quiet, but the development of will can take a long time to build to that point. It is even possible, though rare, for demons to talk their siblings into joining them. On the whole, however, your time may be better spent running.
Please note that native AU characters cannot be angels, including exiles, for Plot Reasons.
Not all Angels have missions. Some few unfortunates are abandoned by the God-Machine, either not taken back at the conclusion of their missions or not given a mission at all when they are put on the ground. The general term for these unfortunates is Exiles, and they occupy a strange space between angels and demons, trusted by neither.
Unlike their mission-bearing counterparts, Exiles cannot Fall - to Fall is to rip oneself away from the God-Machine, and you can't rip away from what you aren't connected to. You can't break rules you haven't been given. Instead, exiles have to learn to live with making their own decisions and giving their own orders, lest the freedoms they aren't prepared for overwhelm them and drive them mad. Angels are creatures of purpose; so are demons, even if that purpose is just surviving.
Unlike demons, exiles do not have a Cover by default, and those that do have them are shaky in them, unable to mesh with humanity closely the way that the Unchained do. Many are destroyed, destroy themselves, or degrade into slivers controlled only by the most basic of their parameters. Some few are offered a second chance, another mission from the God-Machine, seemingly out of the blue - and it is an offer, in a strange way. Rejection of the mission is an instant Fall. For some, it's a relief to finally be welcomed back to the fold - for others, it's a chance to throw off the last tie to a creator who clearly considers them disposable anyway.
Please note that native AU characters cannot be angels, including exiles, for Plot Reasons.