Information on Religion and such
As you already know the Kingdom of Eldast (for the most part) primarily worship the three Gods of Humanity as they're called. The God of War, the God of Knowledge, and the God of Death. Countless other religions exist throughout the Kingdom though the majority question such beliefs as they can readily see the miracles of the three Gods of Humanity, where are the miracles of these other religions?
God of War
The God of War is said to be the first King and founder of the Kingdom, each of the seven royal families are his descendants and are considered to carry both actual Divine Power and Divine Grace for being his descendants.
It is from these seven families that the next ruler is chosen, the seven houses collectively deciding on who should next take the throne from among their youth whenever the last passes. What process they use is unknown, but it is certain that every ruler of the Kingdom has been a demigod, the Divine blood within them so strong as to bear the closest connection to the God of War.
Clergy of the God of War are incredibly war-like, every initiate being trained in some form of martial techniques during their training in case they need go to war. They oversee the Kingdoms many orphanages for the children of soldiers who die in service to Gods, Kingdom, and People. Commonly they can be found tending to the people's spiritual health, spreading the teachings of God and priest alike to those in the most dire need of support.
Two sacred grounds exist for the Church of War: the Royal Palace of the Divine City from where the current Ruler sits upon the Bloody Throne, living Demigod and voice of the order. And the Heart of War, a vast fortress monastery built upon the Bastion Mountains from which the militant arm of the Church guard the realms of the Mortal Races.
The militant arm of the Church of War is the Cult of the Burning Sword, an order of knights raised from birth to the art of warfare and bloodshed set with only two purposes: Guard the Mortal Realm from demon-kind and enforce the will of the Church of War.
Common acts of worship to the God of War include ritual sacrifice of goats and cattle, dedication of the foes they slay to the deity, and the offering of one's own blood on specific holidays.
God of Knowledge
The God of Knowledge is known as the Lord of Libraries to most for it is said that much of the knowledge that forms the basis of the Kingdom's lore is from Him. His Church claims no descendants of his bloodline exist in the mortal world, but also ask what use are such to the wonders of the Crystal Tower, the heart of Magic in the Kingdom.
Clergy of the God of Knowledge are typically scholars, scribes, and mages who dedicate a portion of their time to spreading the gift of knowledge to the masses. They fund, oversee, and support the creation of countless basic scholastic academies across the kingdom for those who can afford it and orphans to attend. Clergy of the God of Knowledge are often somewhat reclusive buried as they are in their own studies and research, though most take the time to administer the faith to the people.
The most devoted of the God of Knowledge's believers will claim every library a holy ground to the God Himself, but in truth there exists only the Crystal Tower. It is the God's greatest gift and creation, a master piece of divinity and magic that towers over even the Royal Palace of the Divine City, playing home to the heart of magical education and study in the kingdom.
The militant arm of the Church of Knowledge are the Keepers of Knowledge, an incredibly odd order of spellsword scholars set on the task of safeguarding knowledge across the Kingdom and reclaiming that which was lost. Unlike the orders of the other Gods only those who volunteer and pass a series of test are allowed into the order rather than being born into it.
Common acts of worship to the God of Knowledge include writing down prayers and scraps of knowledge before nailing them upon the doors of any place of worship for the God, the burning of incense, and gifting of books/scrolls/etc. to others.
God of Death/Lady of the Grave
The God of Death, the unrelenting existence that enforces the final peace of death throughout the land. The Lady of the Grave who tenderly watches over the graveyards where the dead are put to rest, her comforting embrace ensuring an unending and peaceful slumber for those who past as she guides them to the after-life. A God of two faces, two existences merged perfectly into one yet separate all the same. Their children are many for all those untainted pass into the After-life to be watched over by the Lady's gentle care.
Clergy of the God of Death and Lady of the Grave spend most of their time caring for graveyards, preparing funeral rites and graves, and seeing to the peace of mind of those who have lost loved ones. While they build shrines, temples, and churches to worship most clergy of the two are wandering missionaries. Setting out to administer funerals for those in need, care for the myriad graveyards, and establish new ones when need be.
Every graveyard built by the clergy is truly a sacred ground, a gate to the After-life for the souls of the dead, but most prominent of them is the Unending Mausoleum of the Divine City. It is there that the bodies of Eldast's rulers, Heroes, and the greatest of soldiers are interred before being brought to the After-life by the Lady of the Grave herself. Or so the scriptures say. To be laid to rest in the Unending Mausoleum is an accomplishment that would bring honor to a dozen generations of descendants.
The militant arm of the Church of the Death are known as the Knights of Silence, their origins are unknown and their order is shrouded in mystery. Of all the militant orders the Knights of Silence are the most feared for is it not the instinct of humanity to fear the unknown?
Information about the Land and it's Management
The entirety of the Kingdom is broken down into nine dominions. One among them is ruled over by the King or Queen directly, the Divine City the seat of power granting the dominion the title of the Divine Dominion. Each of the seven royal families hold power of their own dominions, the lands themselves being named after the royal family line that holds power there. Finally, but not the least among them, is the Bastion Dominion which is managed by the Grand Marshal of Eldast who oversees the dominion to ensure the demons never break through.
Below the rank of dominion are provinces which are each centered around one (rarely two) city which is given management of the lands that fall within it's borders. In order to classify as a city the location must have a population of at least one million Eldastian citizens, a great church to the three Gods, and an Adventurer's Guild of comparable rank to the status of city. Provinces are controlled by a council of nine, made up of the heads of notable houses and rulers of important townships most often.
Beneath the rank of province are townships which are based around one to three towns depending on the area which oversees the villages below it. In order to classify as a town the location must have a population of at least a hundred thousand Eldastian citizens, contain temples to the three Gods, and an Adventurer's Guild of comparable rank. Townships are often ruled by a single noble house though in some rare places they are led by elected members.
Even further down is the rank of district which are generally centered around several villages led by a council of elected elders from the district's villages. In order to classify as a village the location must have a population of at least a thousand, contain shrines to the three Gods, and an Adventurer's Guild of comparable rank.
Finally, below those are settlements simply termed Hamlets for anything that doesn't meet the classifications above. They could be single family farms in the depths of the wilderness to settlements with tens of thousands of workings that fail to meet the requirements of advancement.