12. The Adeptus Arbites

Enforcers of Imperial Law

The Adeptus Arbites enforce Imperial law across the domains of humanity.

Their duty is not to prevent every theft, assault, or murder. Such matters are usually handled by local police, militia, guild guards, noble retainers, or planetary enforcers.

The Arbites intervene when crimes threaten Imperial authority.

Their concerns include rebellion, sedition, tithe evasion, corruption among governors, attacks upon Imperial institutions, interference with recruitment, and organized resistance to Terra’s decrees.

They exist to ensure that every world remains loyal, productive, and obedient.

The Lex Imperialis

The Lex Imperialis is the immense body of law governing the Imperium.

It includes decrees, precedents, treaties, rights, obligations, punishments, and interpretations accumulated across thousands of years.

No single Arbitrator knows every law.

Specialists, judges, legal savants, cogitators, and archives help determine which statutes apply to a case.

Imperial law may govern:

• Tithe obligations

• Planetary succession

• Treason

• Sedition

• Heresy connected to civil authority

• Interference with Imperial officers

• Military desertion

• Illegal possession of restricted weapons

• Destruction of Imperial property

• Forgery of official seals

• Rebellion

• Harboring declared enemies

Local customs may continue as long as they do not contradict Imperial law.

Arbites and Local Enforcers

The Arbites should not be confused with planetary enforcers.

Local forces answer to governors, nobles, guilds, municipal authorities, or planetary courts. They handle ordinary crime and public order.

The Arbites answer to Imperial authority beyond the planet.

This distinction matters when a governor is suspected of treason.

Local enforcers may remain loyal to the governor. The Arbites are expected to arrest the governor if sufficient authority and evidence exist.

Relations between the two forces range from cooperation to open hostility.

Precinct-Fortresses

Arbites operate from heavily fortified precincts.

A precinct-fortress may include:

• Courtrooms

• Detention cells

• Armories

• Evidence vaults

• Interrogation chambers

• Barracks

• Vehicle bays

• Communication arrays

• Execution facilities

• Sealed archives

• Emergency command centers

• Defensive walls and gun emplacements

These structures are designed to withstand riots, invasion, and planetary rebellion.

If local government collapses, the precinct may become the last functioning center of Imperial authority.

Judges

Senior Arbites officials are commonly known as Judges.

They interpret Imperial law, direct investigations, authorize major operations, and issue sentences within their jurisdiction.

A Judge may command a precinct, lead a mobile investigation, advise military authorities, or pursue a case across several worlds.

Some are patient investigators.

Others are uncompromising enforcers who believe delay only gives rebellion time to spread.

A Judge’s authority can be immense, but it is not unlimited.

Inquisitors, military commanders, governors, Ecclesiarchal officials, and Mechanicus representatives may dispute jurisdiction.

Arbitrators

Arbitrators are trained law officers, investigators, riot-control specialists, and soldiers.

They may conduct:

• Arrests

• Searches

• Interrogations

• Raids

• Evidence recovery

• Prisoner transport

• Crowd suppression

• Precinct defense

• Counter-rebellion operations

• Protection of Imperial officials

Their equipment is built for close urban combat and control of hostile populations.

Common tools include shotguns, suppression shields, shock weapons, heavy armor, restraint devices, grenades, and armored vehicles.

Investigation

Arbites investigations focus on evidence that a local crime threatens Imperial interests.

A murdered clerk may reveal tithe fraud.

A stolen shipment may lead to a rebel army.

A forged permit may conceal illegal psyker trafficking.

Investigations may involve:

• Witness interviews

• Financial records

• Ballistic evidence

• Surveillance

• Informants

• Confiscated data

• Interrogation

• Archive comparison

• Undercover operations

• Cooperation with other institutions

Arbitrators are often feared because they may transform an ordinary criminal inquiry into a planetary investigation.

Arrest and Judgment

An Arbites warrant may authorize the arrest of powerful officials.

The subject may be a noble, military officer, priest, guildmaster, administrator, or planetary governor.

Making the arrest can be more difficult than proving the charge.

The accused may command private troops, control local courts, or claim protection from another Imperial institution.

Arbites may negotiate surrender, conduct a sudden raid, request military support, or place an entire district under lockdown.

Judgment is often severe because Imperial law prioritizes stability over rehabilitation.

Punishment

Possible penalties include:

• Fines or asset seizure

• Loss of title

• Imprisonment

• Forced labor

• Penal service

• Transportation to another world

• Execution

• Servitor conversion

• Collective punishment

• Dissolution of an organization

• Removal of a planetary ruler

Punishments vary according to local conditions, legal authority, and the severity of the threat.

Franz should use the harshest penalties carefully rather than treating every minor offense as an automatic death sentence.

Riot Control

The Arbites are trained to contain mass unrest.

They may use:

• Shield formations

• Tear gas

• Shock weapons

• Suppression grenades

• Water or chemical projectors

• Armored transports

• Loudspeaker commands

• Targeted arrests

• Restricted firing lines

• Heavy weapons when escalation is authorized

Their purpose is usually to restore control, isolate leaders, and protect Imperial infrastructure.

A peaceful protest, food riot, cult uprising, and organized rebellion should not be treated as identical situations.

Rebellion

When rebellion spreads, the Arbites may become a military force.

Precincts can defend strategic sites, gather loyalists, secure communications, and hold out until reinforcements arrive.

Arbites often possess detailed knowledge of local government, infrastructure, criminal groups, and potential rebel leaders.

This makes them valuable during the early stages of an uprising.

If the planet falls, surviving Arbitrators may conduct resistance operations or preserve evidence for later Imperial retaliation.

Tithe and Government Investigations

The Arbites closely monitor obligations owed to the Imperium.

They may investigate:

• Missing tithe shipments

• False population records

• Hidden military stockpiles

• Illegal local armies

• Manipulated succession

• Disappeared Imperial officials

• Unauthorized trade

• Repeated production failures

• Forged exemptions

• Deliberate obstruction of recruitment

A failed tithe may result from corruption, rebellion, famine, invasion, or administrative error.

The Arbites must determine which explanation is true before judgment is passed.

Jurisdictional Conflict

Arbites operations may conflict with other institutions.

Examples include:

• An Inquisitor seizes an Arbites prisoner.

• The Mechanicus claims evidence as sacred technology.

• The Ecclesiarchy demands control of a heresy trial.

• A general refuses the arrest of a vital officer.

• A governor declares that local law protects the accused.

• A Rogue Trader presents a warrant overriding restrictions.

• The Navy refuses access to a vessel under investigation.

These disputes may be resolved through law, negotiation, political influence, or force.

Both sides may possess legitimate authority.

Corruption Within the Arbites

The Arbites are expected to stand apart from local politics, but they are not immune to corruption.

An Arbitrator may accept bribes, protect informants, falsify evidence, obey a compromised Judge, or become loyal to the world they were meant to police.

Precinct isolation can also create rigid local traditions that no longer reflect wider Imperial law.

A corrupted precinct is especially dangerous because it can use legitimate warrants, archives, and weapons to protect criminal authority.

D&D 5e Mechanical Use

Arbites investigations can use:

• Investigation

• Insight

• Perception

• Persuasion

• Intimidation

• Deception

• History

• Tool proficiencies

• Faction reputation

• Legal warrants

• Evidence tracking

Arbites NPCs often function as armored soldiers, investigators, veterans, or commanders.

Suppression shields may improve Armor Class, while shock weapons may deal lightning damage or temporarily prevent reactions.

Arrest-focused encounters should offer surrender, negotiation, pursuit, and evidence recovery rather than requiring every scene to become lethal combat.

Arbites Player Characters

An Arbites character may be:

• An Arbitrator

• A detective

• A riot-control officer

• A precinct survivor

• A legal investigator

• A prisoner escort

• A fugitive Judge

• An officer assigned to an Inquisitorial retinue

Their duties may conflict with party loyalty.

A practical Arbites character should be capable of cooperation and recognize that law must sometimes be interpreted under extraordinary conditions.

The Arbites in Play

The Adeptus Arbites can support adventures involving:

• Investigating tithe fraud

• Arresting a protected official

• Defending a precinct-fortress

• Breaking a criminal syndicate

• Recovering stolen evidence

• Preventing rebellion

• Escorting a dangerous prisoner

• Exposing a corrupt Judge

• Resolving disputed jurisdiction

• Surviving a planetary uprising

The Arbites represent the law of a distant empire.

Their presence reminds every governor that local power ends where Imperial authority begins.