The realm can have Pretender Emperors, of which there can be four, all having a claim on the actual emperor's title. Each gets an Emperor title. The four emperors, being Eastern, Western, Northern and Southern, can create the Pretender Emperor title depending on their culture. The Pretender Emperors get a CB on each other and the real Emperor.
Most of the gods in the mod won't be real or won't ever show up, although there will be some that will.
The realm itself has only been in chaos for roughly 30 years, although it has been in decline for the last hundred odd. For the however long before that it was ruled by the Amarians, who practise the Imperial Faith, that tiny little red thing in the top left hand corner. The Imperial Faith worships eight dead emperors (most didn't last for long) and allows Divine Marriage. The head of the religion is the ruling emperor, although he doesn't get any extra CBs or anything for it. The religion only allows men to hold positions, and so all realms with the religion will be stuck on Agnatic succession. Descendants of the Emperor will get a Sayyid-like trait and the Emperor will get a better version of it. The starting Emperor is going to be an Inbred, Hedonist, Greedy, Gluttonous, Cruel, Arbitrary idiot (Pretty much the sole reason the Empire collapsed).
The other Imperialists are a sort of watered-down version of the Imperial Faith, created when the Emperors tried to convert people to their religion. They only worship the first Emperor, don't allow Divine Marriage and have no religious head. The only positions they allow women to hold are army flanks and the Spymaster equivalent. Those of the Five worship five of the dead emperors, instead of the eight of the Imperial Faith but are otherwise the same as the other Imperialists. Each of the Imperialist factions will have small differences and the ability to reform the faith into one Imperialist one. Northern Imperialists get have a Pretender Emperor.
The Ducaritans have a religious head with a kingdom title. The central Ducaritans are ruled by a pretender emperor and the religious head is a vassal of him. The North and South Ducaritans are heresies of the Central Ducaritans. They have no religious head. All Ducaritans can have Absolute Cognatic succession and are a militaristic society, with the ability to raid and declare wars of conquest on single counties. North, South and regular Ducaritans are all tied to a culture each.
The Red Warriors get the ability to raid but not wars of conquest. They have Agnatic-Cognatic succession and no religious head. They can have a festival for summer and can hunt some sort of giant desert creature for prestige. The Red Warriors will be like the Norse, in that most people will be of one culture. If possible I'll have it so that about one in every 50 Red Warrior children will have a trait that gives them a lot more Diplomacy and Learning skill, with a minus from Martial.
The Cult of Fire is going to be really awesome. They will have the ability to raid and a 30% more damage modifier. They will not be able to declare wars of conquest and will not be confined to one culture, instead being spread across all of them. Members of the Cult of Fire will get a Fire Cultist trait, giving them +Martial and Intrigue. The main aim of playing as a Fire Cultist is to capture enough people and throw them in the volcano, with the Melt decision. Melting prisoners will give a piety and prestige bonus. Melting enough people will allow the Fire Cultists to bring back their evil immortal skeletal volcano god master, Harnathor (good name?). He will have the Immortal trait and probably at least 60 in every stat, being an evil volcano god and will become the head of the religion. Fire Cultists can be of any gender and any culture. Villainy is very inclusive.
The Communion of Naling follow the Prophet Naling, who taught that the Amarians were evil oppressors. Due to this the Communion has a relations malus and Holy War CB toward any Imperialists. Their head of religion is a secular leader and they have any sort of succession rules. They will have a Communion Authority bar, can hold temples and can celebrate every Spring and Autumn.
The Taelran worship animalistic nature spirits. They will be able to hold temples due to seeing them as pointless and just another building. About half of the Taelran will be Merchant Republics and they can all sail up rivers and conquer any county, although they cannot raid. There will be no head of the religion and women can serve as priests. The Taelran can take concubines and are limited to Agnatic Ultimogeniture.
Clurenchiacs have a strong, pope-like leader. They will have full cognatic succession and be limited to Gavelkind. Clurenchiacs will be able to hold gatherings where they eat a certain type of food. A large species of man-eating spider will be a creature that could be hunted by them as a coming of age ceremony. A child would need a good martial skill to kill it and would get a trait for doing it. Only 1/5 will be able to kill the creature, another fifth get killed and the rest don't have anything happen. One of their heads is a Pretender Emperor.
Hidithosians are very similar to Clurenchiacs, like Sunni and Shia or Catholic and Orthodox. Hidithosians can holy war Clurenchiacs and vice-versa. While Clurenchiacs hunt giant spiders Hidithosians hunt normal bears.
Ragricists have a vassalised duke-level religious head. They have military religious orders but no religious head. Ragricists have the ability to cut an arm off of their prisoners, giving them the Maimed trait. They are a river-obsessed religion and can hold a celebration of the river every spring. Ragricists have a lot of children, represented by a fertility bonus and can use the Ultimogeniture succession system.
The Syathosians get a bonus to diplomacy and divine incest. The main feature of the Syathosians is that most of their realm is made of one-holding provinces, with all the holdings concentrated in one area. The Syathosians do not have a religious head and women can hold any position.
The Mercolians get the Autocephalous Patriarchs thing and the ability to subjugate other Mercolians. Their religious head is a Pretender Emperor who holds the title. The Mercolians can hold military parades and gladiator games. They start with higher Legalism tech.
The Culinthians have the ability to study for years and get a trait about knowing everything about the religion, taking about four or five off every stat for three years in return for a pretty good trait. Their land is divided into independent counts and they do not have a religious head or the ability to proselytise.
The Hammerers are a fanatical religion. All members get a +Martial and can go on a pilgrimage to their capital city. They can hold massive hunts, like how Christians in vanilla can hold a Grand Tournament. Their head of religion has a king-level title and is independent. They can call crusades or whatever the equivalent is. The Hammerers are named as such due to the few of them that carry around hammers wherever they go, for use on heretics. The religion is fine with whatever succession method.
Phew, that took a while.