The Immaculate Order is the state religion of the Realm, a more formal and organized outgrowth of the Immaculate Faith that originated during the Shogunate era. The Immaculate Order grew hand in hand with the Realm, providing theological legitimacy to the Scarlet Empress's rule .
The Immaculate Philosophy is a fatalist, caste-based theology. The central tenet of the faith is that everything in Creation has an assigned role ranked by its ability to control essence. Humans are superior to animals, and Dragon Blooded are superior to human, and Dragon Blooded are themselves required to husband and expand their essence-manipulation abilities to achieve greater enlightenment. An individual who lives a virtuous life is consequently reincarnated as a progressively more powerful essence wielder until they emulate the lives of the Immaculate Dragons, the five heroic Exalted who deposed the Anathema.
The Immaculate Philosophy also emphasizes the same roles and obligations for Gods. Under Immaculate teachings, mortals do not speak to Gods, intercession and priestly duties are handled by the Dragon Blooded, who as essence-wielders are better equipped to do so.
Practically, the Immaculate philosophy encourages obedience and worship exclusively of the Dragon Blooded; by following their example and obeying their orders, a faithful follower ensures that he will eventually be reincarnated as one. Immaculate followers therefore do not worship Gods or their Ancestors, and the faith itself is strongly aniconic - Immaculate art frowns upon accurate representations of living things as that smacks of idolatry.
The Immaculate Order is a monastic faith, the basic visible arm of the religion are Immaculate Monks also called "immaculates". Monks, who can be either mortal or Dragon Blooded, study, train and meditate in communal monasteries. Immaculate monks also provide spiritual and social support for the community, they run religious services, and aid the poor and ill. Immaculate monks are required for a variety of rituals - from speaking a child's name to officiating marriages.
In addition to cloistered monks, the Immaculate order sponsors traveling monks. These monks will walk circuits among multiple villages, providing spiritual comfort and officiating over ceremonies as needed. The faith also sponsors special internal agents, called Itinerants who monitor the Order for heresy and criminal activity.
Rank within the order is ill-defined in Exalted supplements. The head of the order is the Mouth of Peace, below her are monastery abbots and other senior officials, although little is said about how they are promoted or recognized.
The Immaculate Order is an arm of the state, receiving a religious stipend from the Treasury every year. In addition, the order receives tithes and donations from the faithful which serve as the bulk of its operational funding.
While an arm of the state, the order operates semi-independently, often serving as the conscience of the Dragon Blooded. Immaculate monks will side with the peasantry over abuses by their lords, and the Order has a well deserved reputation for passive resistance. However, since the monks are also the finest practitioners of Terrestrial martial arts in the Realm, they are more than capable of defending themselves when necessary.
Practically speaking, the Immaculate Order exists to address several problems that the Sidereal Exalted faced. The Order provides a spiritual hierarchy which places the Dragon Blooded at the top of the heap, therefore ensuring the stability of the realm and the Terrestrial Exalted's support for the order. In addition, the Order determines how much essence is transmitted to the Gods; Immaculate monks are more than capable of disciplining weaker Gods and can be a serious threat in large numbers - this compensates for the absence of the treaties and traditional respect held between the Celestial Exalted and the Gods when the Celestial Exalted ruled creation. Additionally, the Immaculate Philosophy ensures that the Underworld around the Realm is weak - because essence is not given up to the dead on the Blessed Isle, the Underworld of the Realm is barren and Lethe is more attractive than staying around.
Finally, the Order provides a rationale for the Wyld Hunt, which from the Sidereal Perspective is its most essential function. Territories which adhere to the Immaculate Philosophy will aid the Wyld Hunt as a matter of course.
The true masters of the Immaculate faith are the Sidereal Exalted. Chejop Kejak in his role as Secretary and Astrologer to the Mouth of Peace, ensures that his pawns are kept on a tight leash. The Sidereals don't really control the Order at this point, it is too large and independent for them to do so, but they are capable of subtly influencing how it operates and use it as their primary lever to influence the realm. Many Sidereals of the Bronze Faction adopt Resplendent Destinies as Immaculate functionaries; and the order is constructed in various subtle ways to hide them - for example, the Order uses elaborate headgear that hides Sidereal Caste Marks.