Lex Imperialis - Imperial Law and the Adeptus Arbites: The laws of the Imperium are upheld by the Adeptus Arbites, the Imperial adepta that serves as the galactic police force of the Imperium of Man, responsible for enforcing Imperial Law on all Human-settled worlds.To aid their investigations, most Arbites Precinct Fortresses boast a cogitator stack containing a massively abridged version of just a portion of those judgements and precedents that fall commonly into the Arbitrators' local purview. These rulings by segmentae Judges, High Marshals and even the Lords Marshal themselves, are designed to expedite the work of an individual Arbitrator.This massive collection of Imperial laws, rulings and judgements alludes more literally to the Book of Judgement. Of course, the entire body of the law is vastly greater than a single volume; no individual could ever comprehend more than a tiny fraction. It has been painstakingly collated over the millennia, and includes the words of the Emperor Himself and every decree and ruling ever passed by the High Lords of Terra.The most ancient articles are written on crumbling parchments, inscribed in unknown tongues by the nameless functionaries of a forgotten age. Every day a hundred new volumes of encoded holoscript and hand-illuminated lettering are added. Volume upon volume sits upon the endless rows of ornate bookcases that fill the Hall of Judgement on Terra.Every row is home to ten thousand volumes, the shelves soaring a hundred metres up towards the vaulted ceilings. Over the ages, the Hall has been expanded and extended many times, so that it is now an entire complex covering many acres, with kilometres of corridors, levels, and rooms.Scholars, scribes, and law lords pace the time-worn marble floors, while above their heads, on the narrow gantries and ladders that cover the shelf stacks like a spider's web, crawl legal assistants and low-ranking functionaries, searching through the detritus of judgement for solar weeks and months at a time to find just a single reference.Every Adeptus Arbites Judge, at some point in their career, attempts a pilgrimage to the Hall of Judgement, there to study the full intricacies of the law. Many spend long Terran years there, for the most heinous, subtle, or far-reaching crimes often require a lengthy process of research to pass judgement.While the Dictates Imperialis are extensive, the huge volume of prior cases and sometimes contradictory rulings can make it difficult to determine the correct decision. In especially complex cases, it may take standard centuries to reach an outcome -- a Judge may spend their entire life deliberating, scrutinising, and trying to fathom out the issues, only to pass their work on, unfinished, for others to continue.Millennia later, though the accused are long dead, a ruling is finally made and justice must be meted out upon the distant descendants and those obscurely associated with the original transgressor.The Imperium of Man is ultimately a theocracy, and although the Arbites wield and police temporal authority, religious concepts make up the bedrock of Imperial Law. The Lex Imperialis holds that the God-Emperor rightfully expects service and obedience from every Human being in the galaxy, and that within the Imperium that expectation is made manifest through the scripture of His laws.To break the Lex Imperialis is not only to disobey a secular law of Humanity's galactic government, it is to violate the immaculate and divine moral order those laws set out as the expressed desire of the god of Humanity. This violation of a divine order is present in every crime the Arbites investigate, and once this is understood the need for harsh methods and stern penalties becomes clear. For the Arbites, there is no such thing as a petty crime.This is also why the heresy of abstractionism --  the attempt by some Arbitrators to go beyond the bounds of the letter of the law in the search for justice -- is so reviled by right-thinking Arbites. It places the flawed and hubristic whims of an individual above the clean, majestic structures of the Emperor's laws as made manifest through the due scripture of His servants. The letter of the law is immaculate -- to claim access to the spirit of the law is to claim equality with the Emperor, a crime and a blasphemy which no Arbiter should countenance.There are a number of broad crimes the Arbites constantly find themselves fighting. There are crimes of destabilisation, committed on scales taking in whole planetary populations. These are the waves of anarchy that can break across a world from disobedient anger at adepta rule, or the criminal loss of discipline in the face of disaster or famine.It can be panic at imminent or actual invasion, or a hive-, continent-, or planetwide religious fervour that skews the perspective of the masses and sees them in flagellant processions or hysterical mass confessions rather than keeping the wheels of the Imperium turning.Where a planetary governor cannot restrain their citizens the Arbites must take the lead and set the example, breaking rioters, crushing panics, and showing the mob the meaning of Imperial loyalty and discipline. Invariably, when the Arbites must take such action, the governor will be called to account for his or her loss of control, and few survive their verdict.It is said the Lex Imperialis allows that crimes of destabilisation may arise from raw passions ineffectively contained. Crimes of sedition have no such mitigation -- they result from the cold and careful intention to strike at the perfect machinery of Imperial rule.Blasphemy, heresy, the spreading of freethinking propaganda, and the deliberate and knowing defiance of Imperial Law are all crimes of sedition, as are physical and moral assaults on the instruments of Imperial rule. A mind capable of deliberate sedition could be capable of anything, and the punishments for it are ruthless and terrifying to contemplate.To enforce every mandate within the Lex Imperialis is a nearly impossible task. These codices of law are so enormous and erudite that few individuals can claim to know all of their secrets or loopholes. Even the Judges of the Arbites must regularly confer with archive-savants and librarium cogitation engines in order to make their rulings.Working for the local planetary Enforcers or powerful nobles during the all-too-rare trials, the legal experts make up a group of rare legal minds. These steadfast scholars spend solar decades poring over the Lex Imperialis, learning its every nuance and interpretation.