These planets are the grotesque pinnacles of human population density, encased in steel, ferrocrete, and misery. The natural surface is obliterated, buried beneath layers of sprawling city-continents known as hives. Spires pierce the toxic atmosphere, housing the nobility in opulence above the cloud layer, whilst billions of common citizens toil in the lower manufacturing districts. The air is recycled and stale, often smelling of ozone and unwashed bodies. Down in the sunless Underhive, law collapses into gang warfare and mutant scavenging. Resources are non-existent; water is reclaimed from waste, and food is processed from corpse-starch. The planet is a consuming engine that inhales raw materials and exhales armaments, sustained only by constant off-world imports.
Devoted entirely to the worship of the God-Emperor, these worlds are owned directly by the Ecclesiarchy. The planetary crust is a geoscape of mausoleums, cathedrals, and processional avenues. Skies are choked with incense smoke rather than industrial smog, and the ambient noise is the low, constant thrum of billions chanting in unison. There is no industry here save for the maintenance of relics and the housing of pilgrims who flock in the trillions. Statues the size of mountains loom over vast graveyards, and the planetary governance is a rigid theocracy where heresy is the only crime and prayer is the only currency.
Contrary to the pastoral ideal, an Agri World is a relentless industrial machine of biological extraction. Entire continents are flattened into monoculture fields, hydroponic lakes, or livestock pens. The air is thick with chemical fertilisers and pesticides aggressive enough to strip the paint from shuttles. There are no forests or wild animals; the ecosystem has been utterly purged to maximise yield. The population is sparse compared to a Hive World, consisting mostly of indentured labourers and servitors piloting building-sized harvesters. These worlds are the breadbaskets of the Imperium, yet the workers often starve, as every grain is tithed to feed the insatiable hunger of nearby Hive Worlds or Crusade fleets.
On these worlds, humanity has regressed to a pre-industrial state, governed by hereditary monarchies and warrior aristocracies. The populace tills the soil with wooden ploughs and fights with swords, black powder, or primitive plate armour. High technology is viewed as magic or divine providence, often controlled exclusively by the ruling class or off-world visitors. The Imperium maintains a distant presence, often represented by a single Governor living in an orbital station. Tithes are paid in raw resources or regiments of rough-riders and shock troops, valued for their superstition, loyalty, and familiarity with hardship.
Feral Worlds are savage, untamed frontiers where humanity exists in hunter-gatherer tribes or Iron Age societies. The environment is usually hostile, dominated by mega-fauna, carnivorous flora, or extreme tectonic activity. The people are hardened survivors, engaged in constant warfare for territory and resources. Language is often degraded into dialects of Low Gothic. The Imperium leaves these worlds largely untouched, monitoring them to ensure genetic purity or to harvest recruits for the Adeptus Astartes, who prize the brutal resilience naturally cultivated by such harsh living conditions.
These planets are dedicated manufacturing hubs, distinct from Forge Worlds by their lack of Adeptus Mechanicus sovereignty. They are dominated by surface-level factories, refineries, and processing plants that churn out consumer goods and low-grade military equipment. The atmosphere is a toxic haze of soot. The workforce lives in hab-blocks adjacent to the factories, their lives dictated by shift whistles and production quotas. Unlike the religious precision of a Forge World, an Industrial World is gritty, dirty, and utilitarian, driven by commerce and the demands of the sector rather than the cult of the machine.
A Mining World is a hollowed-out shell, its surface scarred by strip mines and its crust riddled with deep-core shafts. The air is often unbreathable due to dust or released subterranean gases, requiring sealed enviro-suits for all surface activity. Settlements are usually subterranean or fortified against the harsh environment. The population consists largely of penal labourers or indentured clans, living short lives of back-breaking work in claustrophobic darkness. These worlds provide the raw ore, promethium, and crystals that fuel the Imperium’s forges.
Sovereign domains of the Adeptus Mechanicus, Forge Worlds are planets terraformed into factories for the machine cult. The surface is a geometric puzzle of metal, piping, and vents expelling heat from the planet’s core. Magma is often tapped for geothermal power. The population consists of Tech-Priests, Enginseers, and cybernetic Skitarii legions, alongside millions of lobotomised servitors. The atmosphere is dry and hot, filled with binary cant and the screech of metal. Here, technology is not invented but rediscovered and ritually constructed; every bolt and gear is consecrated to the Omnissiah.
These worlds closely resemble the template of ancient Earth (Terra) before its urbanisation. They possess a balance of self-sustaining agriculture and urban centres. Cities are large but not planet-covering, and wild areas still exist. The population enjoys a standard of living relatively higher than the hive masses, with functioning infrastructure, police forces, and public transport. However, the Imperial presence is felt through monolithic administrative buildings and the watchful eye of the Arbites. They are generalists, paying tithes in a mix of resources and manpower, serving as the stable, bureaucratic backbone of the Imperium.
A logistical nexus for the Departmento Munitorum, these worlds are vast warehouses on a planetary scale. The surface is covered in fortified depots, hangars, and sorting yards. There is no production here, only storage and distribution. Mountains of lasguns, oceans of promethium fuel, and continents of rations are catalogued and shipped out to war zones. The population is an army of scribes, clerks, and loaders, obsessed with inventory and protocol. The bureaucracy is so dense that supplies can be lost for centuries, and the theft of a single crate is punishable by death.
Located at the junction of stable Warp routes, Port Worlds are the commercial hubs of the void. They are heavily urbanised but transient, their economies driven by trade, fuelling, and repair services for merchant fleets. The culture is a melting pot of void-born superstition and sector-wide commerce. Huge orbital elevators or gravity wells ferry cargo between the surface and the void ships anchored above. These worlds are often rife with smuggling and cold trade in minor xenos artefacts, tolerating a level of criminality to keep the spice and plasteel flowing between systems.
These are artificial habitats floating in the deep vacuum of space, ranging from hollowed-out asteroids to cathedral-like orbital constructs. Life here is entirely dependent on life-support systems; a failure in the scrubbers or a hull breach means death. The inhabitants, often void-born, have pale skin and a slightly different physiology due to low gravity. Claustrophobia is a constant companion, and society is strictly hierarchical. These stations serve as listening posts, research facilities, or lonely outposts watching over silent systems.
Fortresses in the void, Naval Stations are the drydocks and headquarters for the Imperial Navy’s Battlefleets. They are massive, armed to the teeth with lance batteries and void shields, capable of withstanding fleet bombardments. The station revolves around the maintenance and berthing of cruisers and battleships. The population is strictly military: naval officers, armsmen, and gangs of ratings pressed into service. Discipline is brutal and absolute. The station echoes with the bosun's whistle and the clang of repairs, serving as a projection of Imperial might.
The seat of Imperial power for an entire sector, this world is a hub of politics, administration, and intrigue. It is typically a Civilised or Hive World, but adorned with the grandeur of high office. The Governor here holds the rank of Sector Commander, ruling over dozens of star systems. The architecture is monumental, designed to intimidate and impress, housing the sub-sector courts of the Adeptus Terra and the Astropathic choirs. It is a magnet for nobility, petitioners, and spies. Wealth flows freely here, alongside corruption, as governors jostle for favour and influence.
A planet currently consumed by active conflict, a War World is a landscape of trenches, craters, and ruin. The original classification matters little; it has been converted into a meat grinder. The atmosphere is choked with smoke and dust. The only industry is the recovery of the dead and the repair of warmachines. Civilians are refugees, conscripts, or collateral damage. The ground shakes with constant artillery barrages, and the soil is poisoned by chemical weapons. It is a place of mud, blood, and heroism, where the Imperial Guard fights to hold the line.
Death Worlds are planets where the biosphere itself is actively hostile to human life. This category includes jungle worlds with carnivorous plants, ice worlds with freezing temperatures, or volcanic worlds with unpredictable tectonic annihilations. The flora and fauna are hyper-evolved predators; everything bites, stings, burns, or poisons. Human settlements are fortresses, constantly besieged by nature. The inhabitants are renowned for their physical prowess and survival instincts.