Types of Planets
Just as the people of the Imperium live in hugely varied environments, so too do their cultures vary immensely.
The Imperium’s most populous worlds are its hive worlds. The populations of these planets are so high that the people live in huge cities, truly immense many-layered structures that reach high into the sky, each housing billions of individuals. Hive worlds often provide much-needed labour, their manufactoria producing mountains of war material and other goods to meet the Imperial tithe demands. Most hive worlds started out as relatively hospitable places but have become severely polluted, the areas outside the hives reduced to ash wastes or radioactive desert by the never-ceasing industry of the great cities. Equally dangerous can be the hives themselves. The crime-ridden, poverty-stricken areas, almost always found in the most polluted and decrepit lower levels of the underhive, are home to violent gangs, criminals and assorted scum as well as mutants and heretical cults who hide there from the authorities.
These farming planets, in their own way, are as vital to the Imperium as its hives. These planets are given over entirely to the production of food, which hive worlds cannot produce in sufficient quantities to keep their huge populations from starving. Many a world has whole continents given over to livestock or fields of crops. Some agri-worlds are covered in oceans teeming with fish and a few are far stranger - worlds covered in edible fungus, scoured by swarms of nutritious insects or gas giants home to flocks of flying creatures. A few planets are used solely to provide clean water to nearby hive worlds. Agri-worlds are sometimes ruled directly by the Administratum, to help ensure that their produce is grown and harvested with maximum efficiency.
Much of a forge world is like an immense factory, with industrial complexes soaring into the sky and mine workings burrowing deep into the crust. Forge worlds build great numbers of complex machines, like tanks or spacecraft parts. They are ruled by the Adeptus Mechanicus, whose training and research facilities are located there, along with the grand cathedrals to their deity, the Omnissiah, in which the Archmagi of the Tech-Priests enact the grandest, most complex rituals to honour the Machine God. The Adeptus Mechanicus’ fleets, its tech-guard armies and, most formidably of all, the Titan Legions, are also all based on forge worlds. The forge worlds are sovereign ground and the Adeptus Mechanicus is loath to allow anyone on their surface other than Tech-Priests and the legions of menials who serve them.
These worlds are rich in one or more of the raw materials required by the Imperium's manufactoria and forge worlds. The people here are likely to be slaves or penal workers who live out their lives mining and transporting massive quantities of metallic ore, rock, minerals, frozen gases or some other useful or precious substance. Mining worlds tend to be rather inhospitable places, and many do not even possess a breathable atmosphere, though a few may support a greater variety of life and support developed cities and even hives.
These worlds are split into geographical areas with widely varying levels of advancement and culture. Depending on the prevailing governments, these might be countries, states, power blocks or tribal homelands. It may be the case that higher levels of technology and wealth are concentrated around original colonisation sites. Other planets might exhibit gross variations in culture due to environment, with areas weak in natural resources being similarly weak in terms of military power, economic muscle and so on. Some planets preserve a great divide due to ancient tribal taboos, religious notions or plain old-fashioned habit. A great many worlds of the Imperium fit into this broad category, but no two are alike in the way they realise these divides.
These planets are populated by folk who have lost access to all but the most basic of technologies. Farming, simple machines such as pulleys, windmills and the like are known, but propelled flight, automatic weaponry and even powered vehicles are likely to be rare or non-existent. These worlds are often said to be the most politically harmonious of all the planets of the Imperium, because their peoples know their place.
These worlds are populated by tribal peoples largely living without the assistance of maintained technology. This may be due to a failed colonisation project, religious preferences, cultural choice, environment or some other reason. They may be aware of the Imperium in some fashion but are unlikely to know much more than something about a large group of distant people living in the stars. These planets are frequently unsuitable for later colonisation, either due to the circumstances which drove the natives feral or because the natives themselves actively resist new people settling on their lands. People of feral worlds can range widely in culture, from Grox-hunting tribes of ancestor worshippers to wild-eyed, post-apocalyptic road warriors, fighting endlessly amongst the toxic, sand-strewn ruins of their civilisation.
These worlds are dominated by religion and acts of devotion. It may be that these places saw the birth of a famous saint or formed the battleground for a particularly important war. Often studded with temples and shrines, these worlds are frequently controlled by the Ecclesiarchy and may form training grounds for members of their Adepta.There are also the dark mirrors to these places of Imperial devotion - fallen worlds where the inhabitants offer up ceaseless prayer to the Dark Gods. These places of obscene sacrifices and bloody rites are not suffered continued existence for long.
Somewhat akin to shrine worlds are the cemetery worlds, were large areas of the planet are given over to care for the dead. Cemetery worlds may mark the site of a huge battle, or they may be covered in gigantic mausoleums each dedicated to a particular Imperial noble. In contrast rare cemetery worlds may be covered in fields of endless modest plots containing the remains of the inhabitants of a nearby hive world.
Otherwise known as paradise worlds and sometimes as garden worlds. These holiday worlds are the playground of the Imperial nobility. They tend to be of outstanding natural beauty and the population of such worlds are dedicated to pampering the important visitors they receive. Pleasure worlds are often very cultured places, and many have sections of their populace dedicated solely to producing works of art or music. Casino complexes, opulent restaurants and huge ballrooms are often found on such worlds. There is a darker side to pleasure worlds, particularly those who cater to the tastes of the more depraved guests they receive. Some pleasure worlds contain large developing cities and other major settlements.
The existence of these planets is rarely made obvious but there are many of them throughout the Imperium. Travel to these worlds is forbidden except for the most well-informed and heavily armed expeditions, and even then only with a very good reason. Death worlds, alien empires or planets where the creatures of the warp have broken through into realspace are all examples of quarantined worlds, as are planets wracked with plague. Some worlds are quarantined because no one can fathom the origins of what has been found there, be it mysterious artefacts or ancient cities - it is thought better to live in ignorance of what lies on such worlds than risk it becoming a threat. Other worlds are quarantined because every expeditionary mission there has failed to return. Planets are often quarantined by the pronouncements of Inquisitors, especially if they have uncovered some warp taint or xenos infestation that cannot be cleansed. Many quarantined worlds possess great resources that would be extremely valuable to the Imperium if they were properly explored and exploited, but there are enough tales of ancient horrors awoken on sinister alien worlds that few adepts would try to defy a planetary quarantine.
There are a great many worlds in the Imperium that can be classed as war zones. The Imperium is constantly at war and in those wars whole planets can burn. Massive campaigns can envelop dozens of systems and hundreds of worlds, many of which are utterly devastated by orbital bombardments and artillery in planet-spanning battles that last decades. Long-term war zones are hellish places where death comes quickly. The Imperium can field truly immense armies of millions of men, grinding their way across a devastated planet and reducing cities to rubble. Mercenaries flock to such places, hoping to leave soon after with their ships loaded with pay. Deserters and escaped prisoners form bands of pirates, preying on any ships unable to defend themselves or roam the war-torn planets in feral packs stealing and killing. The Administratum sends colonists from overcrowded worlds to populate war-torn worlds after the fighting has ended but the wheels of the Imperium grind slowly and a world can lie devastated for centuries before any effort is made to resettle it. These places can be some of the most ghastly in the Imperium, with ravaged environments, cracked planetary crusts, burnt-out cities and plains covered in the bones of the fallen.
These worlds have minimal, even non-existent, life traces. This results from ecological catastrophe, devastating internecine war, Imperial or alien intervention or no attributable cause.
Planets which are too dangerous to support widespread human settlement. Types vary from world-wide jungles that harbour carnivorous plants and animals to barren rockscapes strewn with volcanoes and wracked by ion storms. These worlds are near-impossible to colonise but must be properly explored which necessitates the provision of outposts and other facilities. Some harbour rich mineral, vegetable, animal or gaseous resources.
These worlds have only recently been discovered by the Imperium and are home to a relatively small number of colonists. The Administratum may not have even had sufficient time to fully explore the world and set up government. Frontier worlds can be a refuge for those who want to escape from the repressive Imperial regime (for a time at least), though they can also be a destination for those who want to escape its justice too, and have a reputation for lawlessness as a result.