The Nine Hells of Baator form the Lawful Evil plane among the Outer Planes and are the principal home of devils. Baator is ruled by Malgathar the Destroyer, whose conquest and reorganization of the plane transformed it into the infernal empire known today.

Baator is divided into nine descending circles: Avernus, Dis, Minauros, Phlegethos, Stygia, Malbolge, Maladomini, Cania, and Nessus. Each possesses its own environment, settlements, institutions, and ruler or governor, but all remain part of the same hierarchy beneath Malgathar.

Infernal society is highly ordered. Rank determines authority, duties, privileges, and access to resources, while contracts, law, military command, wealth, information, and political influence shape advancement within the Hells. Competition between devils is constant, but it takes place within a system whose continued operation ultimately benefits those powerful enough to rise within it.

Before the Nine Hells

Baator existed long before Malgathar was confined there.

Ao created the plane as part of the original structure of the Outer Planes, and it already possessed its own environments, native inhabitants, settlements, and ancient structures before the arrival of the Destroyer. Scattered communities and local powers occupied different regions, but no single authority governed the plane as a whole.

After the Last War of the Gods, Malgathar was driven from Eldareth and confined to Baator. Weakened but far from powerless, he began conquering the territories around him and imposing his authority upon the plane.

Over time, his dominion expanded. Existing regions were fortified, roads and controlled passages were established, settlements were absorbed or replaced, and the territories under his control were reorganized into the nine circles known today.

Ancient structures predating this conquest still survive in scattered parts of Baator. Some have been incorporated into later infernal construction, while others remain abandoned beneath cities, fortresses, glaciers, or remote wilderness.

The Infernal Order

Malgathar created several of the earliest Archdevils during the period in which his control over Baator was still being established. These powerful children served as commanders, administrators, advisers, and agents before the Nine Hells had taken their present form.

As Baator expanded, Malgathar assigned territories and responsibilities according to their abilities. Later Archdevils arose through other means. Some descend from older infernal lineages, while others earned their position by rising through the hierarchy.

Archdevilhood is therefore a rank and office as much as a matter of ancestry. Baalzebul, ruler of Maladomini, is among the most famous examples of a devil who rose through the infernal hierarchy rather than being created as one of Malgathar's children.

Control of a circle is not necessarily permanent. A ruler who fails catastrophically can be stripped of authority, demoted, imprisoned, or replaced.

Asmodeus stands at the highest point of this system beneath Malgathar. From Nessus, he coordinates much of the day-to-day government of Baator and exercises authority over the rulers of the other circles on Malgathar's behalf.

Devils and Fallen Celestials

Devils are infernal beings native to Baator. They are not fallen angels or corrupted celestials.

A celestial that falls from its former nature remains a fallen celestial rather than becoming a devil. Such beings may serve Baator, hold infernal offices, or become deeply altered by prolonged association with the Hells without changing their fundamental origin.

Zariel, High Marshal of Avernus, is the most prominent example. She holds authority comparable to the Archdevils who govern the deeper circles but remains a fallen celestial rather than a devil.

Rank and Advancement

Every devil occupies a recognized place within the infernal hierarchy.

Advancement may come through military success, political influence, magical accomplishments, accumulated wealth, effective administration, valuable contracts, or the failure of rivals. Higher rank brings greater authority and access to increasingly important positions within Baator.

Major promotions can also transform a devil physically. Infernal rites and powerful magic may reshape a promoted devil into a stronger form suited to its new responsibilities, while severe demotion can strip away power and reduce a devil to a lesser state.

Such transformations are part of infernal advancement rather than the origin of devilkind itself.

Infernal Law and Contracts

Law governs ownership, authority, punishment, rank, contracts, debt, property, and recognized obligations throughout Baator.

Infernal contracts allow that system to extend beyond the Hells. Devils may offer wealth, magical assistance, protection, information, political support, military aid, or other services in return for property, favors, service, information, or claims upon a mortal soul.

The precise wording of an agreement matters. Devils are well known for interpreting contracts to their own advantage, but properly formed agreements can bind the infernal party as firmly as the mortal one.

A soul reaching Baator after judgment and an infernal power possessing a recognized claim over that soul are not necessarily the same thing. Infernal law determines what rights accompany such claims, while the broader fate of souls within the Outer Planes remains the subject of religious and planar debate.

Travel Between the Circles

The Nine Hells descend in order from Avernus to Nessus.

Most travelers entering Baator through the Astral Plane or established planar routes arrive in Avernus. Reaching the deeper circles usually requires passing through controlled passages that connect one circle to the next.

These routes are closely monitored. Gates, roads, bridges, tunnels, and planar crossings may require authorization, payment, sponsorship, or inspection before passage is permitted.

The River Styx crosses Avernus and Stygia and provides another important route into and through Baator. Its presence also connects the Hells to portions of the other Lower Planes, making control of its banks strategically important.

Avernus

Avernus is the first circle of Baator and the principal military region of the Nine Hells.

Its landscape consists of vast rocky badlands, ash plains, volcanic ridges, deep ravines, rivers of magma, old battlefields, and stretches of barren ground beneath a dark and smoke-filled sky. The terrain remains dangerous even far from active fighting, with unstable ground, volcanic eruptions, flammable gases, and sudden fires common across large regions.

Much of Avernus has been heavily fortified. Broad military roads connect legionary camps, supply depots, training grounds, arsenals, siege yards, watchtowers, and defensive strongholds. Fortresses guard the principal routes deeper into Baator, while major Styx crossings are protected by docks, patrol stations, observation towers, and permanent garrisons.

Avernus is maintained as a prepared war power even during long periods of relative peace. Armies train there, reserves are assembled, war machines are tested, and supplies are stockpiled against invasion or future campaigns.

Scattered throughout the circle are ruins predating Malgathar's conquest, along with remains from the wars that followed his exile. Some old fortifications have been incorporated into modern infernal defenses, while others stand abandoned beyond the principal military routes.

Zariel, High Marshal of Avernus

Avernus is governed on Malgathar's behalf by Zariel, a fallen celestial and ancient military commander.

Zariel fought against Malgathar during the Last War of the Gods and pursued him into Baator after his exile, believing that imprisonment would eventually allow him to become a threat again. The campaign that followed lasted long after the war on Eldareth had ended and ultimately led to her fall.

Malgathar later granted her command over Avernus and its armies. Zariel is not an Archdevil, but her authority within the circle is comparable to those who govern the deeper Hells.

She remains an active military commander and oversees the readiness, deployment, and defense of much of Baator's infernal legions.

The High Redoubt

The High Redoubt is Zariel's mobile command fortress.

Rather than remaining permanently anchored to one location, the fortress can relocate across Avernus and is often positioned above strategically important regions, major garrisons, Styx approaches, or passages leading into Dis.

The Redoubt contains command chambers, communications facilities, military records, officer quarters, landing areas, and a substantial defensive garrison. It serves as a headquarters from which Zariel can inspect forces, oversee exercises, coordinate deployments, and respond rapidly to threats across the circle.

It is sometimes referred to informally as Zariel's Redoubt.

Avernian Reavers

Avernian Reavers are enormous siege walkers constructed for the infernal armies.

They are rare, expensive machines designed to breach fortifications, support major assaults, and withstand attacks that would destroy ordinary siege equipment. Their arrival is usually associated with campaigns or military exercises of considerable scale.

Reavers are weapons rather than living infernal beings. Their construction and maintenance draw upon engineering from Avernus and advanced magical systems developed elsewhere in Baator, particularly Cania.

Hellfire Keep

Hellfire Keep is the divine realm of Malgathar and one of the oldest major infernal strongholds in Baator.

The fortress occupies a vast volcanic plateau and has expanded repeatedly since Malgathar first established his power within the plane. Massive walls, bastions, barracks, armories, siege yards, command halls, foundries, military roads, and fortified gates extend across and beneath the complex.

The foundries of Hellfire Keep produce weapons, armor, siege equipment, and specialized military hardware, but the realm is first and foremost a fortress and seat of divine military power.

Malgathar's own halls lie deep within its fortified core. Archdevils, generals, and senior servants may be summoned there when he chooses to intervene directly in the affairs of the Hells.

Malgathar is not confined to Hellfire Keep. His imprisonment binds him to Baator as a whole, and he may travel freely throughout the plane.

Dis

Dis is the second circle and the domain of Dispater.

Dark mountains, steep canyons, iron-rich ridges, and engineered roads dominate much of the landscape. Fortified bridges, checkpoints, prisons, watch posts, and settlements become increasingly common as travelers approach the center of the circle.

There stands the Iron City of Dis, the largest urban center in Baator.

The city extends across an enormous basin and surrounding highlands, with towers, walls, bridges, administrative districts, workshops, markets, warehouses, prisons, and residences built primarily from blackened iron, dark stone, and other heat-resistant materials. Some surfaces remain hot enough to injure exposed flesh.

Dis is one of the principal points of regulated contact between Baator and outsiders. Recognized merchants, diplomats, contract seekers, mercenaries, and travelers can conduct business there, provided they accept the scrutiny and restrictions imposed by Dispater's administration.

Dispater and Internal Security

Dispater is one of Malgathar's oldest Archdevils and oversees much of Baator's internal security and counterintelligence.

His agents investigate treason, espionage, corruption that threatens infernal institutions, suspicious movements, and conspiracies within the hierarchy. Important visitors to Baator may be watched from the moment they enter Avernus, with information passing through networks ultimately connected to Dis.

Dispater is famously cautious and rarely trusts any single source of information. Surveillance networks overlap, officials monitor one another, and sensitive districts frequently alter routes, checkpoints, and security procedures.

His paranoia has not made his administration ineffective. Dis remains one of the best organized circles of Baator precisely because Dispater assumes that anything left unguarded will eventually be exploited.

The Iron Tower

The Iron Tower rises above the central districts of the Iron City and serves as Dispater's principal seat.

Much of the circle's most sensitive intelligence passes through its offices, while extensive prisons and secure chambers lie beneath the surrounding districts.

High-value prisoners are commonly kept in Dis when information, leverage, or future negotiation makes execution undesirable.

Minauros

Minauros is the third circle and the domain of Mammon.

Most of the circle consists of immense marshlands filled with polluted water, deep mud, unstable ground, fumaroles, and sudden geysers. Rain, sleet, and hail fall regularly, while dark volcanic ridges and rocky uplands provide some of the few dependable routes across the mire.

Minauros is the financial center of the Nine Hells. Banks, treasuries, lending houses, procurement offices, resource exchanges, and institutions dealing with debt and ownership operate throughout its principal cities.

Mammon understands wealth as both possession and leverage. Coin, precious metals, magical objects, property, credit, debt, and access to resources can all be turned into political influence or military power.

The Sinking City

The city of Minauros stands upon ground increasingly incapable of supporting its size.

Foundations settle, streets sink, buildings tilt, and entire districts require constant reinforcement. Laborers and engineers continually raise roads, rebuild foundations, strengthen retaining structures, and recover usable material from areas already lost to the marsh.

Older levels of the city lie beneath the present streets, creating extensive buried districts filled with abandoned buildings, collapsed foundations, forgotten vaults, and infrastructure from earlier phases of construction.

Mammon refuses to abandon the city despite its condition. Too much wealth, infrastructure, and political importance have accumulated there for relocation to be considered acceptable.

Jangling Hiter

Jangling Hiter, the City of Chains, hangs above one of the deepest regions of the marsh.

Its foundations are suspended from enormous chains anchored into basalt pillars, cliff faces, and fortified towers around the surrounding basin. The arrangement allows the city to avoid the unstable ground below.

Jangling Hiter is strongly associated with custody and enforcement. Prisoners, debtors, seized property, bonded laborers, disputed assets, and valuable collateral may all be held there while infernal claims are resolved.

Chain devils are especially common within its administration and security forces.

Phlegethos

Phlegethos is the fourth circle and the shared domain of Belial and his daughter Fierna.

Volcanoes, magma rivers, ash fields, calderas, smoking fissures, and frequent earthquakes dominate the landscape. Even regions far from open lava can reach temperatures dangerous to unprotected travelers.

Phlegethos contains some of Baator's most important courts and legal institutions. Major disputes involving powerful officials, important contracts, conflicts between infernal territories, and questions of precedent may be brought before judges operating within the circle.

The layer is also known for heavily regulated entertainment and indulgence. Wealthy devils and approved outsiders travel there for theatres, gambling houses, private clubs, fighting arenas, luxury establishments, and other pleasures permitted under infernal law.

Belial and Fierna

Belial is one of Malgathar's older Archdevils and possesses extensive experience in infernal politics, law, punishment, and negotiation.

Fierna, his daughter, is particularly skilled at understanding desire and using temptation, pleasure, ambition, and emotional leverage to influence others.

They govern Phlegethos together, though their interests and supporters do not always align. Their cooperation has endured because each possesses strengths the other finds useful.

Abriymoch

Abriymoch is the principal city of Phlegethos.

The city is built within the immense interior of a volcanic caldera, with districts carved into the surrounding walls and connected by bridges, stairways, tunnels, terraces, and fortified galleries.

Courts, palaces, government chambers, prisons, wealthy residences, and entertainment districts occupy many of the upper levels. Lower districts grow progressively hotter and contain workshops, military facilities, holding cells, and passages descending toward the volcanic depths.

Some of the most serious sentences issued by infernal courts are handed down within Abriymoch before being carried out elsewhere in Baator.

Stygia

Stygia is the fifth circle and the domain of Levistus.

Much of the circle consists of a vast black ocean sealed beneath enormous sheets of ice. Rocky islands, frozen coastlines, drifting ice fields, and deep fractures break the surface, while violent storms and frequent lightning cross the dark sky.

The River Styx remains open along much of its course and provides one of the few reliable waterways through modern Stygia.

The circle was not always so completely frozen. Older records describe a much more navigable sea crossed by infernal ships and surrounded by active ports and coastal settlements. Its present condition dates to Malgathar's punishment of Levistus following a major betrayal within the infernal hierarchy.

Many old routes now lie beneath the ice. Sunken ships, abandoned ports, flooded structures, and remnants of earlier settlements remain preserved within or below the frozen sea.

Levistus

Levistus is one of Malgathar's oldest Archdevils and is particularly associated with intelligence, infiltration, manipulation, and betrayal.

Although he retains authority over Stygia, Malgathar imprisoned him within the ice as punishment for his actions. Levistus therefore rules through agents, intermediaries, servants, and extensive intelligence networks rather than acting physically across the circle himself.

His agents are especially active beyond Baator, where they gather information, cultivate informants, recover infernal property, conduct covert negotiations, and pursue matters the Hells prefer not to address openly.

Levistus has also become closely associated with bargains offered to the desperate, trapped, or condemned.

Tantlin

Tantlin is the principal city of modern Stygia.

The settlement existed before the freezing and once served as an important port along the open ocean. Much of its original waterfront now faces an immense frozen expanse, though access to the nearby Styx has allowed the city to remain a significant center of travel and trade.

Tantlin is filled with merchants, agents, informants, contract brokers, foreign representatives, and travelers moving between the Lower Planes. Information changes hands almost as frequently as goods, and many visitors assume that someone is watching them from the moment they arrive.

Cold Fire

Lightning strikes in Stygia occasionally produce pale flames known as cold fire.

These flames draw heat from their surroundings rather than radiating it, causing frost and ice to spread around whatever they touch. Cold fire usually burns only briefly but can be exceptionally dangerous in enclosed spaces or near unprotected travelers.

Malbolge

Malbolge is the sixth circle and the domain of Glasya.

The circle consists largely of steep black mountains, broken escarpments, narrow valleys, unstable slopes, and vast boulder fields. Rockfalls are common, while major avalanches can bury roads, settlements, and fortifications with little warning.

Permanent communities survive within caves, protected valleys, reinforced strongholds, and structures built directly into the mountainsides. Roads commonly pass through tunnels or beneath protective walls designed to reduce the danger of falling stone.

Malbolge serves as the principal penal region of Baator. Serious infernal offenders, dangerous prisoners, disgraced officials, and captives too valuable to destroy may be confined within its numerous fortresses and prison complexes.

Glasya

Glasya is the daughter of Asmodeus and an Archdevil in her own right.

She is known for her political ambition and exceptional ability to identify loopholes, procedural weaknesses, and assumptions within infernal law. Those same talents make her particularly effective at overseeing those who attempt to evade punishment through technicalities.

Glasya was not the first ruler of Malbolge. The circle was previously governed by Moloch, one of Malgathar's early Archdevils, before control eventually passed to her.

Osseia

Osseia is Glasya's principal fortress and seat of power.

The complex is built directly into one of Malbolge's great mountain formations, with towers, terraces, buttresses, and defensive walls extending across the surrounding slopes.

Extensive prisons reach deep beneath the visible fortress. Secure cells, vaults, holding chambers, interrogation rooms, administrative offices, and heavily warded sections allow prisoners of very different kinds to be kept safely within the same complex.

The upper sections of Osseia are considerably more comfortable, containing Glasya's court, residences, galleries, gardens, and chambers used for political business.

Maladomini

Maladomini is the seventh circle and the domain of Baalzebul.

The landscape is covered by the remains of abandoned construction. Ruined cities, exhausted quarries, empty mines, unfinished roads, broken aqueducts, abandoned fortresses, polluted waterways, and discarded infrastructure stretch across enormous regions.

Much of this destruction is the result of repeated redevelopment rather than war.

Baalzebul is obsessed with improvement and frequently orders successful projects replaced because he believes a better version can be built. Over centuries, this has left Maladomini covered in the remains of cities, roads, government buildings, and public works that were completed, judged inadequate, and abandoned.

The process has gradually depleted local resources. Stone and metal are stripped from older ruins, materials must increasingly be imported from other circles, and some projects remain unfinished while plans are revised yet again.

Baalzebul

Baalzebul is a true devil who rose through the infernal hierarchy rather than being created as one of Malgathar's children.

His exceptional ability as an administrator, planner, and political operator eventually earned him Archdevil status and control of Maladomini.

Baalzebul is highly competent, but rarely satisfied. A functioning system can still be unacceptable to him if he believes it could operate more efficiently.

His rise has also made him one of Asmodeus's most significant political rivals. Baalzebul covets the position of highest authority beneath Malgathar and believes his advancement through the hierarchy proves that his ability is equal to those born into greater power.

Flies are strongly associated with Baalzebul and are common throughout the polluted and abandoned districts of his circle.

Malagard

Malagard is the largest functioning city of Maladomini and the current center of Baalzebul's administration.

Broad avenues, monumental government buildings, towers, bridges, archives, civic districts, and carefully planned infrastructure distinguish it from many of the abandoned cities surrounding it.

The city is never truly finished. Districts are routinely redesigned, buildings replaced, roads altered, and public works reconstructed as new plans supersede old ones.

Despite this constant redevelopment, Malagard remains one of the most administratively important cities in Baator.

The Infernal Archives

Maladomini contains extensive repositories of official records gathered from across the Nine Hells.

These archives preserve decrees, appointments, property records, tax records, infrastructure plans, registered contracts, military requisitions, administrative correspondence, treaties, regulations, and centuries of institutional history.

The records are carefully organized, but the classification systems used by infernal administrators can be difficult for outsiders to navigate without trained assistance.

Grenpoli

Grenpoli is one of Baator's principal centers of formal diplomacy.

Foreign representatives, planar powers, recognized mercantile interests, and other groups permitted to negotiate openly with the Hells may maintain compounds or send delegations there.

Violence and weapons are tightly restricted within the principal diplomatic districts. Agreements reached in Grenpoli remain subject to infernal law, and security is deliberately strict to prevent negotiations from becoming another arena for open warfare.

Cania

Cania is the eighth circle and the domain of Mephistopheles.

Frozen mountains, immense glaciers, deep valleys, violent ice storms, and severe cold dominate the landscape. The glaciers move far more quickly than ordinary ice and can alter established routes, crush structures, and seal entire valleys over relatively short periods.

Despite its hostile climate, Cania is far from empty.

Fortified settlements, arcane towers, research complexes, artificer workshops, libraries, observatories, testing grounds, and defensive strongholds rise from cliffs, glaciers, and sheltered valleys. Magical barriers and heated interiors allow substantial communities to survive within an environment lethal to unprotected outsiders.

Cania has become Baator's principal center for advanced arcane research and magical development.

Mephistopheles

Mephistopheles is one of Malgathar's older children and among the most powerful Archdevils in Baator.

His relentless interest in arcane advancement made him increasingly valuable as the Nine Hells expanded. Malgathar eventually granted him Cania, where research too dangerous, secret, or demanding for other circles could be pursued on a far greater scale.

Mephistopheles sponsors work involving planar magic, magical warfare, containment, defensive wards, infernal enchantment, siege magic, communications, artificer engineering, and other advanced fields.

He is also one of Malgathar's most important advisers and a longstanding rival of Asmodeus.

Hellfire

Infernal hellfire existed before the rise of Cania's research institutions, but Mephistopheles and his servants developed increasingly sophisticated methods for controlling and weaponizing it.

Canian artificers use these techniques in hellfire engines, specialized artillery, enchanted weapons, siege equipment, and other military technologies.

Many of these designs eventually reach Avernus, where they are tested and deployed by the infernal armies.

Mephistar

Mephistar is the principal city and stronghold of Mephistopheles.

The city stands upon Nargus, an enormous glacier whose movement Mephistopheles can influence. This allows the stronghold to shift slowly across Cania without sharing the mobility of Zariel's High Redoubt.

Mephistar contains laboratories, artificer halls, libraries, workshops, administrative chambers, fortified residences, magical markets, and research institutions. Its interior is heated and carefully maintained despite the deadly cold outside.

Remote facilities scattered across Cania conduct research considered too hazardous to perform near the city.

Buried Ruins

The glaciers of Cania preserve numerous structures that predate Malgathar's conquest of Baator.

Some are settlements, roads, fortifications, or other constructions left from the earlier history of the plane. Others have origins that remain uncertain.

Canian scholars and artificers regularly excavate newly exposed ruins in search of records, magical techniques, artifacts, and information concerning Baator before the Nine Hells existed.

Nessus

Nessus is the ninth and deepest circle of Baator and the domain of Asmodeus.

The landscape is fractured by enormous chasms, trenches, cliffs, and rifts descending extraordinary distances into the plane. Fortresses, cities, roads, bridges, and defensive works have been constructed along their walls, floors, and upper reaches.

Conditions vary with elevation. High plateaus and exposed ridges can be bitterly cold and windswept, while volcanic vents and geothermal activity make some of the deepest regions considerably warmer.

The geography of Nessus has been heavily fortified. Roads descend through guarded switchbacks and tunnels, bridges cross major rifts, and strongholds control the principal approaches from Cania.

Anyone attempting to reach Nessus through the normal infernal routes must first pass through the eight circles above it.

Asmodeus

Asmodeus is Malgathar's first and greatest Archdevil and the highest authority in Baator beneath the Destroyer himself.

Where many Archdevils specialize in particular aspects of infernal rule, Asmodeus possesses unusually broad abilities. He is an accomplished administrator, strategist, commander, negotiator, political operator, and long-term planner.

Malgathar relies upon him to coordinate the rulers and institutions of the Nine Hells when direct divine intervention is unnecessary.

Asmodeus is usually controlled and courteous in his dealings with others. His authority depends less upon displays of rage than upon his ability to understand competing interests and arrange circumstances to his advantage.

Malsheem

Malsheem is the greatest fortress in Nessus and the working capital of the Nine Hells.

The vast complex rises within and around one of the largest central chasms, with towers, walls, bridges, chambers, military installations, residences, prisons, and administrative districts occupying multiple levels.

Representatives of the other circles maintain offices or permanent delegations there, allowing Asmodeus to coordinate matters affecting Baator as a whole.

Malsheem also contains strategic reserves and elite forces assigned directly to Asmodeus. These troops are deliberately kept deep within the Hells rather than stationed along the exposed frontier of Avernus.

The Senior Counselors

Among the rulers of Baator, Asmodeus, Baalzebul, and Mephistopheles are particularly influential in Malgathar's councils.

Asmodeus possesses the broadest authority and coordinates the infernal state. Baalzebul is one of Baator's most capable administrators and planners, while Mephistopheles provides expertise in arcane development and magical strategy.

Their usefulness has also made them persistent rivals. Baalzebul and Mephistopheles both possess reasons to believe they could occupy Asmodeus's position, while Asmodeus must continually demonstrate why Malgathar continues to trust him above the others.

Their competition is tolerated so long as it strengthens rather than destabilizes the Nine Hells.

Inhabitants

Devils form the dominant civilization of Baator and occupy nearly every level of its military, political, administrative, magical, and commercial systems.

Lesser devils serve as laborers, soldiers, guards, messengers, scribes, attendants, and scouts, while more powerful forms occupy increasingly specialized positions. Infernal society includes generals, magistrates, administrators, spies, artificers, merchants, diplomats, jailers, researchers, craftsmen, engineers, and countless other professions.

Imps are among the devils most frequently encountered outside Baator and commonly serve as messengers, familiars, observers, and minor agents.

Hell hounds, nightmares, and numerous other infernal creatures inhabit the Hells alongside devil society. Some are domesticated or used by infernal forces, while others remain wild.

Outsiders are also found throughout Baator. Gloomfiends may arrive as mercenaries or merchants, Merrenoloths travel along the Styx, night hags conduct business in some settlements, and mortal travelers occasionally enter the Hells through planar routes or deliberate summoning.

Such visitors remain subject to local authority while within Baator.

Natural Hazards

Baator possesses no single climate or environmental danger.

Avernus contains volcanic terrain, unstable ground, smoke, fire, and military hazards. Dis combines extreme heat within the Iron City with dangerous mountain routes and heavily controlled territory. Minauros presents deep mud, polluted water, unstable foundations, and severe storms.

Phlegethos is dominated by extreme heat, volcanic activity, earthquakes, and magma. Stygia combines lethal cold, unstable ice, storms, cold fire, and dangerous waters beneath the frozen surface. Malbolge is plagued by rockfalls, avalanches, steep terrain, and difficult mountain routes.

Maladomini contains polluted waterways, unstable ruins, abandoned infrastructure, and hazardous construction zones. Cania presents some of the most severe cold in Baator, along with moving glaciers and violent ice storms. Nessus combines dangerous vertical terrain with heavily fortified routes and long descents through its great chasms.

Travel

Travel within Baator is possible but heavily regulated.

Roads, bridges, tunnels, ferry routes, planar crossings, and gates are frequently controlled by infernal authorities. Travelers may require documents, contracts, escorts, fees, or permission to enter particular districts or move between circles.

Major cities contain accommodations and services for approved outsiders, though these are rarely provided freely.

The most reliable travelers make extensive preparations before descending beyond Avernus and obtain local information before entering each circle. Conditions change considerably from one layer to the next, and protections useful in one circle may be nearly worthless in another.

Survival

Surviving Baator requires more than resistance to fire.

Travelers moving through several circles must prepare for extreme heat, severe cold, acid, polluted water, unstable terrain, volcanic hazards, avalanches, long-distance travel, and environments where safe food or water may be difficult to obtain.

Infernal authority can be as dangerous as the landscape. Entering restricted territory, violating local regulations, interfering with recognized property, or accepting an agreement without understanding its terms can create problems that ordinary equipment cannot solve.

Visitors should remember that Baator is not a wilderness loosely inhabited by monsters. It is an organized plane governed by institutions that have existed for centuries.

A traveler who survives the environment can still be arrested, indebted, recruited, deceived, imprisoned, or bound by an agreement they did not fully understand.