Note: Most of these were written to nail down the worldbuilding of 'Constant Bearing, Decreasing Range' and 'Delta's Heart', but the rest were purely for fun.

- Warden Weir isn't spliced - he's just badass. He maintains control through sheer brutality and force of personality. Fearlessly wading into splicer fights and breaking them up himself is his favorite sport. He never, ever refers to an inmate by name and has a preternatural ability to match faces to identification numbers.

- Every arriving inmate is issued a metal identification bracelet which is stamped with the number they're meant to go by for the duration of their stay in Persephone. Penal employees are encouraged to refer to inmates by number rather than name, in order to dissuade them from forming attachments. See 'Constant Bearing, Decreasing Range: Prologue' for a more in-depth discussion about the inmate culture surrounding the use of identification numbers.

- Higher ranking prison guards are issued unique asbestos-lined jackets with rubber cores in order to protect them from the harmful effects of some plasmids. Rubber boots and clothing made of ballistic material are also a part of their uniform.

- There's a system of appeals that a prisoner can go through to attempt to secure their freedom, but most everyone knows that the paperwork gets lost the second you file it. A few people become obsessed with getting themselves out through legal means but most just accept that they're going to be here for the long haul. Harold Parson appealed for years before losing hope.

- The commissary is stocked with overpriced, sometimes ridiculous, luxury items to tempt inmates into volunteering for product testing and can be accessed between the hours of 12 PM-6 PM. Food of better quality can also be purchased from the "Sinclair's Deluxe Meals" menu. A lot of people stay sane by buying little luxuries for themselves now and then. But there's a danger in falling too deeply into that mindset and needing those luxuries to get by. The more money they need, the more money they need to earn and the only way most people can earn money, they well know, is by exchanging their health and humanity at Fontaine Futuristics.

- In the beginning, all test subjects were chosen at random, drugged and shipped off to Fontaine Futuristics. After Sinclair implemented the volunteer system, the number of involuntary testing stints dropped, but did not cease. Most inmates are surprisingly stubborn about what they're willing to do to their bodies, even in the face of threat or reward. But Fontaine Futuristics sends Persephone a weekly quota they need filled, which often cannot be done with volunteers alone. Inmates are chosen based on how recently they were last seen Upstairs (See Persephone Slang), how many product tests they've done in their career at the prison and how many favors the guard doing the kidnapping (usually after lights out) owes them. Old timers who have done this multiple times are fairly chill about it and try to get it over with as quickly and smoothly as possible. It's considerably scarier for first timers, for whom they often have to break out the ether.

- Before an inmate leaves Fontaine Futuristics to return to their cell, the lab techs try to make sure that they've used up all the EVE they were given. "Try" is the operative word here. Because ADAM changes, to a small extent, the way all bodily systems operate, there is no reliable way to tell what the level of EVE is in anyone's blood. But after comparing so many individual capabilities and keeping track of the average number of charges a given plasmid holds, they have a pretty good idea of the approximate amount of blasts a person has before they're empty. So it's a general rule among prisoners that they hold onto the last handful of EVE they have left while pretending they're out. It's an easy and very successful ruse. This handful of EVE is most commonly used to play pranks or extract revenge on people they deem worthy of those things. Grudge-holding individuals are given a wide berth by both guards and inmates when they return from Upstairs. This is the issue that gives Sinclair the biggest headache in running the business.

- There's a huge, overt gambling ring headed by Dodge, a former mafia don. His lackeys are always somewhere close by to facilitate bets on splicer fights, games (dice and cards, mostly, but variations on Russian Roulette are also quite popular) and his famed cockroach races. He's also in the business of loans - to both inmates and guards. Every so often, after a fight caused by a gambling dispute or a mysterious death happens, there's a crackdown on his business, but it never lasts. After all, a good chunk of the prison staff are in his pocket too.

- EVE is a strictly controlled substance within the walls of Persephone. Employees must check their own supply of it at reception when they enter the prison and are not allowed to shoot up on the clock (though after seeing the effects of ADAM on the inmates they work with everyday, some of them are understandably more wary of splicing). However, there are definitely employees who make a lot of money on the side through smuggling it in, usually to Dodge, who then sells it at a markup to other inmates. EVE replenishing items are also kept out of the commissary and vending machines. This rule is one of the biggest causes of grief in the prison because it includes cigarettes.

- The Persephone economy is entirely cash-based, in order to facilitate spending in the commissary and the vending machines. The vending machines are the reason it's not monopoly money - Sinclair deemed it too expensive to reconfigure them for fake money and having never run a prison before, didn't recognize the danger in allowing prisoners real cash. Everyone has a spot where they hide their savings and they can usually whip out a wad of cash from nowhere at a second's notice. Stealing from a cell in which its occupant is not present is considered to be an action of the lowest parasitical caliber. But beating up the occupant and then taking their things is fine, as they did earn them with the sweat of their brow.

- Persephone is home to common thieves, murderers and grifters caught up in the wrong grift, but a not-insignificant part of the population are political prisoners who have been imprisoned for their outspoken Collectivist views. These are the ones who actively try to make Persephone a better place than the one they were exiled from, with dreams (urged on by Lamb) of building a more perfect society from below. They go out of their way to help the inmates who are suffering the most as best they can. They are the only ones who do favors for others without expecting recompense (in Rapture, both inside and outside the prison, it is common for every small human interaction to be in some way transactional. everything else has a price, after all). When someone threatens a weaker inmate, if they are able to, they step in to help. If an inmate's political affiliation is known, the prison staff goes to great lengths to house them separately from their fellows. The rare occasions in which they find a way to be together are the thing that keeps them going.

- There's a divide between the Splicys (badly deformed splicers) and the Squares (inmates who may be spliced, but are able to pass as ordinary humans), which is partially staff mandated and partially cultural. The accepted rule of thumb is that the more heavily spliced someone is, the more unstable they are and the more danger they present to the general population. Thus, Splicys and Squares are generally kept in separate cell blocks; A-B for the Splicys and C-D for Squares. A more polite moniker with which to refer to a Splicy is 'A-Blocker.' Interaction between the groups is minimized as much as possible. Their activities are typically scheduled in different time slots. When needs force them to mingle in the cafeteria, they sit at different tables. If a member of one group attempts to sit with another, they are met with ridicule and social ostracization. But the truth is that the Squares are afraid of the Splicys because in them, they see their own future. Sometimes this fear manifests instead as outwardly directed anger, which can lead to devastating violence, more often than not, inflicted by a Square on a Splicy.

- The line between Splicy and Square is a blurry one and based more on physical deformity than anything else. A Splicy could be someone whose single splice led to a very visible, very disabling, physical deformity. A Square could be someone who's spliced over and over but experienced little in outwardly identifiable side effects. But when someone's moved to A Block, there's no doubt about which group they belong to now. There are more Squares than will admit to it who secretly keep up contact with their friends who have gone over to the other side.

- Not all Splicys have lost their minds. The vast majority of them are just disabled individuals who are now dealing with ostracization and loss of status on top of everything else they're going through. But keeping their sanity is a much harder prospect for them, due to their lack of social support, more than any other single factor.

- Splicys - because of reasons which frequently include: not caring what happens to them anymore, wanting to spend what remains of their lives in style or using their ADAM addiction to cope with their negative feelings - tend to volunteer for plasmid tests at a much higher rate than their counterparts. Oddly, this means that they have more money than anyone else in the prison (excluding Dodge). They're the biggest spending commissary customers, with the nicest cells, who eat the best food and have their pick of alcoholic beverages. This does not endear them to the Squares in the least.

- The Plasmid Theater is typically staffed by inmates who have volunteered for the position. Job qualifications are: must be a good-looking Square and have a sense of showmanship. It's one of the most highly paid and sought after jobs in the prison, but few people are good enough at it to make the cut. Inmates who have held the job for a long time are among the highest ranking individuals in the social hierarchy of Persephone.

- The majority of Plasmid Theater shows are non-lethal, public demonstrations of mundane plasmid use, mixed with entertaining tricks and commentary. Accidents do happen, though (most famously when the sleeve of a performer demonstrating uses for Incinerate caught fire in front of a packed theater. Fontaine was not pleased).

- There's something of an underground subculture of the ultra rich, who sponsor gladiatorial fights (which are not supposed to be to the death, but often are) in the Plasmid Theater. Ryan disapproves of them and shut them down when he seized Fontaine's assets, but nearly every other magnate loves them. Security companies looking to make a big investment in equipping their officers with the latest combat plasmids are also treated to private fights, in order to show off the product's potential and hopefully seal the deal. The more sadistic volunteer performers jump at the chance to really show off their powers and with more opportunities to practice, become much more skilled at it than the average plasmid user. Sinclair absolutely hates organizing fights and frequently asks that they be non-lethal (and is as frequently ignored). This is sometimes mistaken for him giving a damn about his prisoners, but the reason it upsets him is solely because a dead inmate is one that he can no longer profit off of. He sets prices for fights higher than an ordinary product test.

- The woman's wing - a building disconnected from the main compound and only accessible by bathysphere - was something of an afterthought and put together in a slapdash manner when it became impossible to house the sexes separately in the main compound. Because of the cutoff between facilities, it has its own acting warden, though she does ultimately report to Weir. Plasmid testing goes on at more or less the same rate here as it does in the main compound, with most of the same rewards. Because of the difficulty of reaching it, the undesirability of working there and its low rank on Sinclair's list of priorities, it is a badly overcrowded, understaffed and under-supplied facility which chews up and spits out workers (not to mention inmates) like nobody's business.

- The woman's wing has a rudimentary infirmary with one overworked nurse, so badly injured inmates must be shipped to the mens' facility to recover, where they might recount tales to the male inmates about how lucky they are to not be living sub-basement (see Persephone Slang). This was actually a strategy of Lamb's through which she passed messages along to her followers in the other facility, in order to coordinate actions and gain information about the goings-on elsewhere.

- Because of the lack of oversight and the sparseness of staff, Lamb had a lot more freedom to move around in the women's wing than she would have otherwise. She gained control of that facility first and from it, orchestrated her takeover of the main compound. Sinclair's long-delayed plans to expand the wing were cancelled after control of Persephone was wrested from him.