- – One of many possible hymns of the Imperial Cult, reeking of Humanity Fuck Yeah and awesome, as quoted from "We Are One" by Triarii, is also the season 2 intro of TTS
"As long as there will be rascals and imbeciles, there will be religions. Ours is without contradict the most ridiculous, the most absurd, and the most bloodthirsty one to ever infect the world."
- – Voltaire
In a broad sense, an Imperial Cult is any religion in which a head of state is worshipped as (a) God. Examples of real (historical) civilizations with an Imperial Cult include Ancient Egypt and the Japanese Empire. On /tg/, it almost always refers specifically to the state religion of Warhammer 40,000's Imperium of Man, and basically
Catholic Juche in Space HERESY!*BLAM*There is no filioque in the Imperial creed!
"Rejoice, for I bring you glorious news. God walks among us."
- – The first lines of the Lectitio Divinatus
It got its start from the Lectitio Divinatus, a spess bible written by Lorgar, Primarch of the Word Bearers, on the worlds conquered by his Legion during the Great Crusade and further perpetuated by believers amongst the crusade fleets. The Emperor, an advocate of atheism, did not approve, and betrayed, attacked, and humiliated Lorgar for it, which pushed his son into the worship of Chaos instead, which in turn ended up setting the Horus Heresy into motion. Afterwards, the Imperium worshiped the atheist even more than ever before. Just as planned.
After the Heresy, the Emperor was entombed in the Golden Throne and was not exactly in a condition to stop people from portraying him as a god, and it was soon discovered that humanity could be united by using this religion to control them far more effectively than the old Imperial Truth ever could. It's unclear if He ever approved of the whole mess, but strange 'miraculous' things keep happening all around the galaxy wherever acts of profound devotion are performed in his name (Living Saints, for instance), and faith in the Emperor has been shown to be a powerful weapon against Daemons. There is something to this whole worship thing after all...
The Imperial Creed
Though the substance of the Imperial Creed can vary from world to world as the Imperium is extremely vast, the Creed itself is deceptively simple. This makes life easier for missionaries who are attempting to bring new planets into the fold as the original superstitions of each planet might be fundamentally incompatible with a convoluted religion with too many doctrines.
Regardless of any other deviations in belief, the basic tenets are as follows:
- Worship the God-Emperor of Mankind as the One-True-God, your Lord and Savior.
- Humanity is perfect and are the dominant form of life in the galaxy, everything else needs to be crushed or subjugated.
So at its simplest, a world can believe whatever it likes, so long as the Emperor is God or at the very least the head God, so on some worlds he might be a god of thunder and lightning, on others he might be the judge of the dead, on others he might just be an almighty paymaster, whilst on others he might be seen as a god of destruction who must be appeased with death... essentially each planet can have its own view of the Emperor. This makes the Imperial Cult an extremely tolerant religion when it comes to expressions of faith, which is ironically at odds with most observers' opinions on what the Imperial Creed is actually about. In addition, the Imperium is so vast and its history so expansive that just about any belief can be matched with something that already exists within the Imperium. Protector god? Space Marines. God of plenty? Agricultural world. God of fire? Salamanders. God of frost? Some world close to its star. God of light? World with weak atmosphere where they live underground. God of machines? Adeptus Mechanicus. The big guy who the plebs think is a god? Adeptus Custodes. And so on. On top of that, the Imperial Cult is perfectly willing to spend centuries or even millennia very slowly shifting a new world’s beliefs to fit closely enough to be accepted.
The Imperial Cult and the Imperium
Where people get confused is with the distinction between the Imperial Cult and the Ecclesiarchy, which are distinct from one another; just as the worship of the pagan Roman Emperor was to the specific rites carried out in Rome. Comparisons are often drawn to the Roman Catholic Church, but a more accurate comparison would be to pagan Rome, which tolerated or ignored the various beliefs of its subject peoples, as long as they acknowledged the Emperor as the high priest of their pantheons in his role as Pontifex Maximus.
The "Imperial Cult" is just a blanket term which covers a multitude of belief systems which are compatible with the Imperial Creed and are tolerated by the Imperium, such as the Cult of the Redemption, Cult of Pure Form, a large variety of Death Cults (but not some of the more extreme ones), as well as a wide variety of Feral or Death world belief systems that have been modified by missionaries to incorporate the Emperor in some form.
The Ecclesiarchy is just the state church, which attempts to bring a level of standardization to how people worship the Emperor and to make relations between worlds relatively frictionless. Unfortunately, even this is a difficult task. The sheer size of the Imperium ensures that various sectors can still have their own variations on how the creed is interpreted, and may have different doctrines or venerate different canonised saints because no one system can control every form of belief that pops up across the Imperium. Needless to say, this translates into a lot of people calling each other heretics even when their interpretations of the Imperial Cult are equally valid as far as the Ecclesiarchy is concerned. Actual violence (outside of planetary affairs) is rare as the Imperium is willing to tolerate infighting between planets only as much as necessary and sectarian divisions are pretty bad for general stability.
Because of this, the issue of Heresy can occasionally come about where different factions disagree with each other on what constitutes acceptable worship of the Emperor, though as per the original tenets of the Creed it takes a considerable level of deviation to truly count as abominable. Typically, this is determined either by the adoption of tolerance (or worse, outright subservience) towards xenos or the outright worship of other deities that are obviously not the Emperor, especially the Chaos Gods. The accusation of heresy still does a pretty good job of silencing debates or threatening people whose views are considered to be too far from the norm, even if they wouldn't actually be viewed as heretics, as it basically means "You are straying too far from the planetary/sector government policy and you need to shut up before we kill you.".
However, it can and does go a bit further than this in day to day life. As the state religion, it does its best to cement itself as the only acceptable way to behave. So whereas the Emperor is the only true god, the High Lords of Terra are the Emperor's living agents, and the Ecclesiarchal priests are the speakers of His word --all of them are to be obeyed without question, no matter how suicidal or pointless their commands may be. Which basically translates as "Do as you are told by your superiors, or else". This generally involves: Working in horrible conditions until you die. If you don't want to do so and are stupid enough to express your views along those lines, you will quickly find out the hard way that the Imperium considers treason to be the same as heresy, since both of those involve refusing to acknowledge the supremacy of the Adeptus Terra.
The only major deviation allowed in the Imperium is the Cult Mechanicus of the Adeptus Mechanicus (and Squats), thanks to the original Treaty of Mars allowing them to practice their own faith. Even so, this hasn't stopped tensions from popping up between the Mechanicus and the Ecclesiarchy. The commonly accepted compromise is that the Emperor represents the Machine God's physical avatar, the Omnissiah. While this compromise satisfies neither side, everyone goes along with it to keep the Imperium functioning as everyone ranked high enough (that is, not a lot) to be able to do something about it being at least somewhat aware of the intimidatingly insane shit they need to stand together to face (there is also the fact that the Emperor intentionally manipulated things so that the Cult Mechanicum was established at the very end of the Dark Age of Technology after the Men of Iron rebellion and before the Age of Strife, and he was probably aware of how exactly he could keep things stable and pre-arranged that as well). Even pious humans outside of the Adeptus Mechanicus, particularly Guardsmen, take the Machine Cult's beliefs seriously as their lives depend upon the technology they use. Squats on the other hand are completely exempted and they do ancestor worship, though the Emperor is considered the greatest and oldest ancestor, which he technically is.
Specific variants of the Imperial Cult
At mentioned there is a huge variation of the sects and subsects of the Imperial Cult, many of which are officially sanctioned, others less so, and just because an expression of faith is considered heretical or unofficial does make them any less of a faithful servant of the Emperor than the next belief structure. Though some of the bloodier cults are more susceptible to corruption than others.
- Confederation of Light: aka the "Ecclesiarchy proper" from M36 onwards. The Emperor sacrificed himself for you and that you should feel bad about it and follow the penitent principles of poverty, generosity and humility. Also heavily linked to the principles of Thorianism: that the
Holy GhostEmperor can work through inspired individuals and give rise to the Living Saints. What the average Imperial who has regular contact with the Adeptus Terra will be believing in as the vast majority of humans never leave their home planet (also home sub-sector or sector if they are temporarily conscripted) and worship one of the many variations.
- Temple of the Saviour Emperor: The old Ecclesiarchy from M32-M36. If the Emperor is a god, and the Ministorum are his divinely appointed agents, then the Ministorum should get all the power and wealth. This belief was directly responsible for causing the barrel of laughs that was the Age of Apostasy. Some still believe in this doctrine, though they keep their mouths shut very tightly if they don't want a trip to the gallows.
- Cult of the Redemption: The Emperor sacrificed himself for your sins, therefore mankind needs saving from its sinfulness; PURGE IT WITH FIRE! Considered too extreme and fanatical for mainstream doctrine, though tolerated as they are willing to go to insane lenghts no normal can handle to squash heretics and aliens.
- Death Cults: There is no single "Death Cult", though most share the common belief that since the Emperor sacrificed himself for your sins, that debt needs to be repaid with sacrifices of Death, Blood or Pain, often in combination. This means their adherents are almost universally incredibly deadly since even the lowest layperson is likely to be able to gut you in any number of imaginative ways. Regularly found engaging heretics in a crusade. The cults who take it too far are susceptible to Chaos corruption.
- Cult of the Pure Form: Takes the doctrine of human purity very seriously. They believe that any tampering with the human body is a corruption and therefore oppose the Adeptus Mechanicus and reject any form of mechanical augmentation to the point that they will even rip it out of themselves after converting to the faith and causing themselves severe physical trauma. Considering even the most fanatical Sister of Battle can have bionics, this is pretty stupid.
- Cult of the Emperor Revenant: almost indistinguishable from the mainstream Imperial Cult aside from its focus how the Emperor gained immortality/divinity through his martyrdom. Most servants of the Ministorum can't see a difference between this and "proper" doctrines, although this belief serves as the basis for several Death Cults and Funerary Sects.
- Night Cult also called the Temple of the True Resurrection in different locations. Believes that you can also gain immortality in death just like the Emperor, but attempts various methods to make it actually happen, including raising the dead through sorcerous or technological means. Understandably, the Inquisition and Ecclesiarchy take dim views on this matter.
- Cult of the Dead Emperor. Main antagonist in the Horusian War first book, they believe that for the Emperor to truly ascend to his divine form, he should die and get freed from his limbo-like-cage. Yeeeeeaaahh... considering what would happen to Terra if this ever happen, you can understand that they are usually spited by the Inquisition or almost any other cult, many times be labelled as heretics.
- Space Marine Chapter Cults: Most Space Marine Chapters reject the Imperial Cult (often with with extreme prejudice and gratuitous violence) and do not consider the Emperor to be a God, holding instead to local forms of the Imperial Truth doctrine. Therefore they are not actually compatible with the Imperial Creed, though individual Chapters occasionally have "He wasn't a god then but is now." as a sort of midpoint. Their specific chapter cults often spread to their respective homeworlds, with the natives crudely mimicking their masters veneration for their creator.