I don’t think it does much good to have complex lists of crimes and their statues and punishments. Instead, some general guidelines should do the trick.
One important element to keep in mind is that the whole system is utterly corrupt. Those with money and power have trials turn out their way in 90% of instances. Only those with enemies of similar stature face anything like fair odds.
As for the poor and downtrodden, they don’t stand a chance. Nowhere in the whole system is there a whiff of justice. It is about money and power and punishment, that’s all.
The wealthy go to Farradan Prison, an unpleasant but relatively safe establishment on the cliff overlooking the south of the city. More like an austere mansion, the massive building has many layers of basements for those who irritate the staff. Those who play along and keep the bribes flowing can live a relatively comfortable life during their stay.
Everyone else goes to Ironhook Prison, which has the Leighter Wing for non-violent offenders, the Pendell Wing for scum and thugs, and the Morvoria Wing for the criminally insane. Those who commit crimes related to spirits and fuel (glowder crimes) are assigned to the sublevels. Kala Level is for those who mess around with electroplasm, lightning oil, and leviathan blood illegally. Simrek Level is below, for those driven mad by contact with ghosts kept there for their own good and the good of society. Then there is Felderstone Deep, buried below everything, where the worst criminals (and the most capable) are put in solitary.
Most of the guards for the Felderstone Deep are ghosts, sometimes hollows. Three people have escaped in the four centuries since the Deep was built, and no one can be sure how they did it.
There are dozens of other prisons through the city. Each bluecoat station has holding cells, and they feed into a neighborhood gaol. Only after conviction and when dealing with significant sentences are people sent beyond those neighborhood gaols. Most of the neighborhood gaols have haunted sections for punishing or killing offensive prisoners. Rats are also a pernicious problem, often causing cuts and lacerations that get infected and risk killing prisoners.
The city also maintains two prison hulks in the harbor, known as the Humps (Greater and Lesser). Both are over a century old, fitted with iron and warding, haunted. In times of massive civil unrest or rioting, hundreds can be detained there. When the authorities have a prisoner who is not to be identified and is to receive especially unpleasant treatment, sometimes that is where they end up.
Some lesser offenders and debtors are warded. They are assigned to an aristocrat, who is responsible for rehabilitating them over a period of years. They are indentured servants, and their level of freedom is determined by their ability to get on the noble’s good side. They are assigned work that will benefit society. This system is heavily abused and can lead to cushy sentences for cronies and absolute hell for those who get on a noble’s bad side. The judges tend to know the nature of the various aristocrats that serve the system by taking wards, and the sentencing can therefore be fairly nuanced. The system is subject to favor banks and political pull.
Levels of Offense
For “lessers” (minor crime), the trial is perfunctory. One lawyer to a side, the judge decides. Punishments include public lashings, fines of up to 1 coin, and gaol time up to 1 year. This is for things like chronic disturbing the peace, petty theft, assault, disrespecting a noble’s coat of arms, injuring someone’s property, and so on.
For “vitals” (major crime), the trial involves a lawyer on each side, three honored aristocrats that render the verdict, and the judge that renders the sentence. Punishments include maiming, torture, fines of up to 5 coin, execution, and hard prison time of up to 30 years. This is for things like killing, major theft, impersonating officials or aristocrats, sex crimes, acting against the government, and so on. The net tends to be cast pretty wide; anyone involved in such acts (even if not the direct perpetrator) can be severely punished.
Then there’s the “glowder” offenses. Any offense that involves using spirits, electroplasm, leviathan blood, lightning oil, or alchemical compounds involving any of those elements escalates in magnitude. The four main categories of glowder crimes are trafficking, assault, compelling, and blurring.
Trafficking is moving, storing, selling, or buying the substances illegally. Assault is injuring or killing someone using methods enhanced by those substances. Compelling is using those substances to force someone to act against their will or unknowingly, mind control or influence or possession. Finally blurring is using those substances to change your own capacity, whether to give yourself an advantage or to change something about yourself.
Glowder offenses open the criminal up to supernatural torture. Executions for glowder offenses sometimes make the criminal into a hollow to serve the state, or serve as a death for powerful state-sanctioned rituals, or other deeply secretive and unpleasant applications. Involving materials that are the life-blood of the city and that keep it from falling to the howling undead wasteland outside means giving up any shreds of humanity the law still has.
For lesser offenses, a criminal can be forced to do some unsavory things. Hefting is the term for carrying the spirit of a victim, who can whisper in the mind. A criminal can be forced to gate a certain number of times, a process of having spirit wardens force a ghost into a person for questioning and torture the ghost can physically feel.
Trials for glowder offenses involve a whisper and a spirit warden in attendance. Together they collaborate with the judge on the penalty for the crime.
A whisper accused of a glowder crime replaces the three aristocrats with three state-friendly whispers.
When ghosts misbehave, most are simply discorporated and destroyed. However, some ghosts have protection as aristocrats, allies of the state, or vouchsafe from a state-sanctioned whisper or spirit warden.
Ghosts capable of remorse can be punished by serving the state in various capacities while anchored in spirit traps.
Incorrigible ghosts who are lucid but evil are given to the spirit wardens. They are taken to a secret location underground outside city walls, where they are tormented. This location is known only as Purgatory. As they suffer, they draw latent electroplasm into themselves, which is distilled down into useable doses. The state then uses this energy to help power the lightning walls.
This is Gameable
The idea here is to have stuff that can make your game better. Knowing about glowder offenses provides useful context for misbehavior. Plus, now there are punishments your crew can interact with. Are they assigned these punishments? Do they need to help out an ally who is assigned these punishments? Are they part of sentencing or carrying out punishments for others?
Consider the warding sentence. Now under the thumb of a noble, who could be soft-hearted and wanting to help reform (and what if the noble succeeded?) or cruel and vindictive, carrying out brutal tortures on their new toy? Or is the noble just greedy and putting these criminals to work in a sweatshop and working them to death?
What if the crew gets jobs regularly from a content aristocrat who retired in Farradan and networks with roguish nobs there, so they can be part of the endless fencing between noble houses that is conducted from inside and outside prison? Or what if a noble hires them to clear his name in exchange for the location of the treasure he stole? With access to visitors from outside, and some freedom inside, this could be a great backdrop for lots of adventures. What if they are hired to break someone out, who is protected in the prison and does not want to leave?
A bit more detail on Ironhook allows you to know where PCs may have been imprisoned before, where their friends and influence lie. Probably only in one wing per influence, rather than the whole prison. There’s room to riff off that for prison tats and old cellmates and that sort of thing. And, if a character is imprisoned, then the character can be an NPC for a bit feeding out news of scores and possible targets while the player runs someone else.
I hope this helps you come up with fun ideas for your Blades in the Dark game!