Imperial Worlds
Designated by function[edit]
Agri-Worlds[edit]
Agri-Worlds are planets in the Imperium of Man entirely dedicated to agriculture. A typical Agri-World is mostly covered by millions of square kilometers of farmland managed by a few million farmers and a couple of spaceport cities/transportation hubs where stuff is loaded onto starships to be sent elsewhere to feed the Imperium's teeming masses. Said ships also drop off huge loads of shit (sometimes literally) to keep things fertile. Others are Ocean Worlds with huge fish farms or Gas Giants with habitable zones and balloon bases that collect airborne plankton and mash them into Soylens Viridens. Their tithes are paid in whatever edible products they grow, which, combined with their relatively sparse population, means that they rarely have to raise regiments for the Imperial Guard. Some still do as need allows, or have a small number kept in the Sector and well supplied. Other Agri-Worlds are defended by Imperial Knight Houses, becoming Knight Worlds. The Administratum has a somewhat dickish tradition - of course - of promoting them all as rural, bucolic paradises regardless of what they are actually like (although worlds like that certainly do exist in the Imperium, it's more likely that they would be pleasure worlds, garden worlds, or simply a barbaric world that hasn't been colonised yet).
So, you're probably wondering how the Imperium makes farming grimderp? Well, it varies a lot by source. Some sources suggest that Agri-Worlds are often pushed insanely hard to produce ever more food to the point that a combination of intensive monoculture and massive pollution eventually causes the total destruction of both the soil and the planet's viability for growing food, meaning the Imperium would eventually starve to death if it weren't for the massive amounts of fertilizers. Other sources will focus on the harshness of labor and the toxicity of said fertilizers turning the planet into a hellish labor-pit where, even if the planet isn't going to die, the inhabitants have a pretty shitty life - one example of this is Nova Thulium, where the air is so thick with toxic chemicals from the fertilizers and the workers are supplied with such limited means of protecting themselves from their effects that people usually die in their early 40s. Nova Thulium has been widely rejected from canon by the fans since it's an Ultramar world, which surely shouldn't be run so inefficiently, even if that kind of mismanagement isn't out of the question for the Imperium as a large. Finally, the last way that Agri-Worlds will be grimdarkened is by focusing on the lives of the natives and making them as shitty as possible - essentially sugar cane and cotton plantation slave labor on a planet-wide scale.
Of course with some creative rewrite you can quite easily ungrimderp some aspect of Agri-Worlds. In example, let's keep Nova Thulium as chemical wastelands, uterly deadly to HUMAN life but not to the plants and animals, as the planet's ecosystem has been manufactured to be extremely fast growing, nutritious and edible, after processing, that absorbs chemical like a sponge. The ecosystem is self-sufficient except for said chemicals. The populous live on domed and sealed settlements with pleasant enough living conditions, and during the harvest seasons the workers use specialized suits to go outside and work. Now to grimdark it. Said suits are a marvel of engineering, long-lasting and easy to maintain; the suits can be used by same family for generations and even have special place within the local religious beliefs. But they are extremely hard to make, so much so that the planet's upper class are made of those that have been able to hoard these suits or have contacts with the their manufacturers. So if a family loses one of them (and possibly its user as well), it's a huge blow to their standing and if they cannot get a replacement suit, it might lead them to take huge loans or other risky actions to get one, which can lead them leaving the world, turned into servitors or debt slaves. Even just the public shame for losing one can lead to discrimination and suicides.
Even when Agri-Worlds are pleasant places, the bureaucracy of the Administratum usually gets in the way. To give one example, the Agri-World of Ceocan was capable of producing enough grain, fruit, vegetables, and fish to feed many worlds, but the entire output of the planet was tasked to only feeding the Mechanicus's operations in the system - along with rendering down the kind of food most Imperial citizens would never taste in their lives down into tasteless nutrition bars. And this decision was made because it was tiny fraction of a percentage more efficient that vat growing their own sustenance.
Cemetery Worlds[edit]
Extremely depressing worlds that are dedicated almost entirely to being huge graveyards. Cemetery Worlds see some religious overlap with Shrine Worlds, and are considered sacred and solemn places by the Imperium at large, especially the Ecclesiarchy. Most if not all of these worlds are not simply covered in row after row of grave plots, though one might assume some Cemetery Worlds are surfaced in nothing but geometrically perfect grave tessellations, broken only by small hills with singular willows to be sad under. Some have cathedrals clad entirely in human remains, or catacombs that reach many kilometers into the planet's crust. Certain Cemetery Worlds are dedicated only to the deceased of certain organizations or sub-sectors, though these are very rare.
These should not be confused with Mausoleum Worlds, which are a subcategory of either shrine worlds or, more usually, Space Marine worlds.
Forge Worlds[edit]
The Imperium's massive workshops. Forge Worlds are planets dedicated entirely to industry, are technically a sovereign world of the Mechanicum, and the property of the Adeptus Mechanicus.
Hive Worlds[edit]
Exist to cram tens of BILLIONS of people onto one planet, obviously Grimdark for underhivers. More realistically, hundreds of trillions seeing as even at a population of roughly seven billion modern Earth is barely inhabited compared to the vast wilderness. And that wouldn't take into account countless cities whose spires sometimes extend past the atmosphere or planet-cities Coruscant style.
To clarify here, if one was to cover the entire land mass of Earth with a city with the population density of Manila (currently the most population-dense city as of 2023), it'd result in a population of roughly 21 trillion. Now one has to imagine the population of something like Terra itself, which is this but turned up to 11 at the least.
Mining Worlds[edit]
"FOR KARL!"
- – A Kin from the DeepRock Kindred. Do we even need to explain.
Mine mine, mining for the glory of the Emprah! Mining Worlds is one giant open-pit mining quarry. These are one of the most important planets as they provide the Imperium the raw materials needed to craft their myriad of killy stuff. As such, Mining Worlds are often situated right next door to a Forge World and are often heavily defended as a result.
Whilst nowhere near the levels of Dead Space, Mining Worlds would have its geography drastically altered and eventually run out of minerals to mine; it would then be either reclassified as a Barren World or a Space Marine training outpost. Most Mining Worlds are lifeless rocky planets anyway, since even the ass-retarded competency of Imperial bureaucracy recognizes that it is far more logistically easier to mine on shit that would not provoke a hostile takeover. Of course, that should be true in theory, until some halfwit accidentally digs too far and activate an underground Necron complex, because surprise surprise! Shit turned out to be a Tomb World. Que expected results.
Expect the only population being filled with Servitors and Deep-Miner landships.
Shrine Worlds[edit]
Shrine Worlds are worlds completely dominated by the Ecclesiarchy. They are famously paved in cathedrals, monastaries, reliquaries and catacombs. While never truly reaching Hive World status, many of these worlds are nonetheless stuffed to the gills with pilgrims, caretakers, priests, and the officers of the Imperial Cult. They make excellent homeworlds for Orders of the Sisters of Battle. Any Guard Regiments raised will be fanatical in their service. Frequently hosts Scholae Progenia as well.
SPESS MAHREEN Worlds[edit]
These are planets claimed by a Space Marine chapter. While typically most Chapters select Death Worlds, Feral Worlds, or Feudal Worlds as a home due to the hardiness of their residents, some of these planets are more civilized or even at a better standard of living than most of the Imperium - the Realm of Ultramar is an obvious example of the latter.
Tithe Astartes planets are notable for being one of only two planet types exempt from the usual Imperial Tithe, with the only other type being Aptus Non (read: planets which have been Exterminatus'd or an unimportant place that is considered Imperial territory but has no tactical or strategic value). This does lead to a few political complications. For instance, Space Marines can technically claim a Hive World for recruiting, and some do, but because the tithe of the world is then denied for the recruiting of guardsmen it creates tension between the chapter and the Adeptus Munitorium.
Designation by development level[edit]
Feral Worlds[edit]
Feral Worlds are places where mankind has regressed to the level of the Stone Age. While they're as primitive as it gets, they are prized for the high quality of their warriors. There are numerous kinds of Feral Worlds, from stereotypical "Neanderthal worlds" (like the ones which spawned the Ogryns) where humans are brutish hunter-gatherers wearing pelts to Techno-Barbarian worlds where everything has gone Mad Max or Waterworld, much like Terra itself in the Age of Strife.
Some Feral Worlds are closer to the Neolithic Age, and have recognizable urban civilization and culture. There isn't a lot of official nomenclature for the numerous sub-variants of these worlds. Imperial Tithes from Feral Worlds tend to be either nonexistent or in manpower for the Imperial Guard. Occasionally these worlds will have some natural resource which the Imperium decides it needs, so they can be colonized by more civilized Imperium citizens or Mechanicum Servitors, who set up isolated bases of operation amidst the "barbarism". Favored for Astartes recruitment due to probably hellish life conditions. If a subsector with an Astartes chapter garrisoned has several inhabited Civilized Worlds, a Hive World for a capital, some Forge Worlds and a Feral World, you can bet your ass the Astartes will be recruiting from that last one.
Feudal Worlds[edit]
Feudal Worlds are planets abandoned by the greater human species during the Age of Strife and for one reason or another regressed back to pre-engine (steam or otherwise) technologies. They are also generally divided into small kingdoms which fight with each other but pay tribute to the Imperium; apparently the Neo-Medieval themes of 40k just weren't enough so they had to add in several actual medieval-themed worlds too. The Imperium deliberately keeps them from progressing further technologically (with only a small handful of exceptions) since the Imperium already works on a form of the feudal system anyway. More importantly, it ensures that the planet's citizens know their place in Imperial society and don't get any ideas about secession into their heads. The big reason why these planets are kept around is because they provide good light infantry for the Imperial Guard; Space Marines like to recruit from here as well due to the martial traditions offsetting the slightly softer life compared to Feral Worlds.
Knight Worlds[edit]
The Knight World is a special variant of planet, somewhere between an Agri-World and a Feudal World. These worlds are only found in planetary systems with Forge Worlds (or at least close enough to them that a short Warp jump is enough to bridge the gap), and are more within the legal vestibule of the Mechanicum than the Imperium. Since Forge Worlds rarely harbor any kind of agriculture, Knight Worlds supply Forge Worlds with the huge amount of food it needs to survive, and sometimes help fulfill their mineral quotas as well. In turn, the Forge World supplies the kingdoms of the Knight World with Knight Titans, huge war machines with which the kingdoms may defend themselves from rampaging megafauna, Chaos incursions, Xeno invaders, and the Knights of other kingdoms. When the Forge World is in need of defense, or a local Explorator is going on a quest, the Knights and their well-trained pilots (and squires, attendants, Household Retinue Troops, etc.) are called upon in whole or in part to "ascend to the stars and fight amongst the gods".
Civilized Worlds[edit]
Civilized Worlds are the 'normal' inhabited planets in the Imperium. Lacking Hives (or at least having one or two per continent at most, usually as the capital of the planet) or Forge-World-scale factories they nevertheless have a decent level of technology and a population in the same ballpark as modern Earth (5-11 billion) or at least low enough that they aren’t either covered with numerous hive cities or one giant city-planet. They can be expected to often have many times Earth’s population (especially since guesstimates about how many people Earth can sustain never accounts for arcologies or their agricultural equivalents). Due to lack of fluff, this may be the most common type of planet in the Imperium, but seriously, are you in the game for a chance to edit wikis in the 41st millenium? Many of Ciaphas Cain's novels occur during campaigns to defend civilized worlds, which actually helped to tone down a great deal of the Grimderp of 40k early editions by actually giving the imperial armies populations and places to defend which you could feel emphatic with; it's good to know even at the beginning of the 42nd millenium there are still snack vendors, cafeterias and pubs.
Pleasure Worlds[edit]
Pleasure Worlds are a subtype of civilized worlds, sporting exquisite wine estates, views Hive Worlders will never even see a picture of, and much more. Essentially tourist traps and vacation spots IN SPEEEHS and predictably restricted to the exclusive use of nobles, senior officials of the Adeptus Terra, and other big shots in the Imperium. These worlds are often hotzones for Slaaneshi cultists, because why not turn some of the Imperium's most powerful men and women to Chaos when they're on vacation? As of 8th edition, even Pleasure Worlds are supporting war by setting up hospitals, providing rare medications and other support.
Designation by status[edit]
Paradise Worlds[edit]
Different from Pleasure Worlds, Paradise Worlds are merely a joy to live on. Either lushly verdant or impressively architectural (or both!), Paradise Worlds are as far from the Imperial front lines as one can reasonably get. As war can and will find its way to Paradise Worlds, no well-known examples have remained in this world classification for very long. Many of the remaining Paradise Worlds are self-sufficient, with farming and housing and industry all balanced perfectly. Many of them are also relics, with histories that span back into the Dark Age of Technology (somehow without civilization-ending calamities). Paradise Worlds are jealously guarded and staunchly defended both politically and militarily. Some Knight Worlds are Paradise Worlds, such as Voltoris, home of House Terryn.
Dead Worlds[edit]
Exterminatus isn't the only way planets die. Ecological disaster, sudden celestial events, alien invasion, someone disengaged from the warp too close to the planet and accidentally the atmosphere... (assuming you can Warp into a star system or near a planet, the lore happily contradicts itself on this constantly because fuck consistency). Unlike Quarantine/Forbidden Worlds (see below), these aren't strictly forbidden for colonization, just that the work required to make them habitable is prohibitively expensive for the negligible gain in resources. Most would require either completely isolated arcologies, underground cities, or huge terraforming projects. Tyranids create these worlds en masse: after they nom all the life on the planet, they will then turn to draining the planet of its core, atmosphere, and any water still remaining before setting off for new real estate.
Barren Worlds[edit]
A sub-classification of Dead World; a Barren World is the Dead World's less awful little brother. It is a world which has never harbored life, nor could without substantial terraforming. Mars in M40 (and M2) is a good example of a Barren World, or would be if it wasn't already a Forge World (and a Hive World in its own right). These worlds are often colonized for mining.
Death Worlds[edit]
Death Worlds are worlds where everything is hostile to Human Life (think Australian outback on crack). Everything. The animals, the plants, plate tectonics, weather, seasons, sometimes even the very air itself is fatal to humans, while being just habitable enough to warrant colonization. Examples include Catachan and the majority of Astartes homeworlds such as Fenris. Sometimes the lethality is artificial, like Krieg's nuclear winter.
Quarantine/Forbidden Worlds[edit]
While it seems cut and dried what kind of planet this is, these tend to have a large spectrum of why they are blocked off and how it is enforced. For the most part, the reason is heresy: the planet has fallen to Xenos influence or Chaos, or simply broken off from the Imperium. Mysterious perceived danger can also be a reason; a planet being a Death World is one thing, but if the last five colonization attempts on a planet ended with the inhabitants mysteriously vanishing, the Imperium is going to block it for settling and generally tell the Inquisition to figure out what is going on. The Inquisition rarely does, and so Forbidden Worlds they remain until everyone forgot why they were forbidden, and they send another settling party down...
War Worlds[edit]
War Worlds are planets locked in eternal war. So what makes these planets different from just any old planet with a war on it? Scale and length; on a War World, generations of soldiers have lived and died. Some planets just have such warlike cultures that even without an external force, they will kill each other (not necessarily for Khorne); usually planets with scarce resources—— such as Zayth, but that's a Hive world—— result in this since the best way to deal with limited supplies is to kill someone else and take their stuff. Some of these worlds just happen to be unluckily situated in a location so strategic that two intergalactic (or merely galactic) factions refuse to acknowledge the sunk-cost fallacy and back down; occasionally even the sunk cost fallacy doesn't apply because of how important the location is.
Many Imperial groups maintain War Worlds as a means of keeping battle-trained troops at the ready. They are useful for Guard and Space Marine recruiting and act as a natural deterrent to planetary conquest or invasion in important areas.
For the most part, these are probably pretty shitty places to grow up in, even by Imperial standards.
An example of a War World was Cadia.
/tg/ worlds[edit]
Imperial Daemon Worlds[edit]
See Terranis in Love and Krieg Spinoffs.