This is mostly focused on the main continent of Khovaire. You don’t have to read it, just wanted to include it.
Time of the Dragons: The three creator dragons created the thirteen planes with the material plane intended to be their final work. But Khyber sought to dominate everything and tore apart her sibling Siberys. Eberron fought Khyber but couldn’t defeat her and so bound her in her coils and became a living prison. Siberys became a ring of golden dragonshards around the planet and the source of magic known as the dragon above. Eberron became the source of all natural life and Khyber became the underdark and spawned all lesser and archfiends known as the Overlords.
Dragons (and Coautls) vs Fiends
The Archfiends and their rhakshasa lieutenants conquered much of Eberron enslaving many races. The dragons fled in the beginning but uncovered the draconic prophecy. With its help and the help of the coautls they managed to beat the fiends and the coautls sacrificed themselves to bind the archfiends in Khyber with the Silver Flame. Some say that instead of dragons and coautls the gods known as the Sovereign Host defeated the fiends.
The Dhakaani Empire
The goblins (hobgoblins, goblins and bugbears) conquered most of Khovaire (the largest continent) and unified it under the empire of Dhakaan. The empire was militaristic with great craftsmanship. However the daelkyr, beings from the plane of madness Xoirat opened gates and sent their minions. The goblins fought them and in the end managed close the gates and bind them in Khyber with the help of the orcish druids known as the Gatekeepers. However the war took a toll on the empire and it fell apart.
Galifar and the civil war
After the end of the goblins, humans came and began to settle Khovaire. The kingdom of Galifar conquered most of Khovaire and was made up of the five nations: Breland, Aundair, Cyre, Karrnath and Thrane. These rulers of these five nations descend all from the royal bloodline of Galifar the Wynarns. This kingdom lasted for hundreds of years until the death of king Jarot in 894 YK who wished his eldest daughter princess Mishann of Cyre to succeed however her siblings, who ruled the other territories disagreed and a war over succession broke out.
The war way a bitter struggle of shifting alliances and gruelling conflicts that tore the land apart and deeply scared the countryside. Everyone lost. In 994 YK the nation of Cyre was consumed in an event known as the Mourning. Almost all inhabitants died and now a dangerous fog hangs over the land. The shock and fear brought the nations to the negotiating table and in 996 YK the Treaty of Thronehold was signed. There were twelve new nations now and Galifar was no more.
The situation now:
It’s been four years since the war and two since the peace treaty has been signed. Some believe that peace will last, others that war will soon break out again. The nations are in a state of cold war, seeking advantages over each other for the conflicts that could lie ahead.
The dragonmarked houses have stayed neutral but sold their services to the highest bidder. They emerged stronger than ever, amassing political power. Now no ruler can afford to break with the dragonmarked houses or face the consequences.
The New Nations
Aundair: A fertile nation that is built on and with magic and used its arcanists in the war
Known for: Fertile farmlands, aristocrats, magic university of Arcanix, lots of magic, fancy wine and cheese
Ruled by: Queen Aurala ir’Wynarn
Breland: Southern nation known for its industry that built large flying fortresses
Known for: Heavy magic-industry, innovative, pragmatic, subterfuge, shady
Ruled by: King Boranel ir’Wynarn
Cyre, now Mournland: Seat of wealthy now a glassed, cursed wasteland
Known for: Formerly art, commerce, culture, Now: Ruins, mist, Lord of Blades, monsters
Karrnath: Martial nation, that used undead as soldiers after multiple famines
Known for: Ale, dairy, lumber, textiles, undead, martial discipline, Blood of Vol
Ruled by: King Kaius ir’Wynarn III
Thrane: Theocracy ruled by the church of the silver flame and used it’s clerics in the war
Known for: Silver flame, divine magic, fine crafts, fruit textiles
Ruled by: Speaker of the Flame Jaela Darn and Council of Cardinals
Darguun: A new nation formed by goblin mercenaries under a warlord during the war
Known for: goblin mercenaries, ancient ruins, warlords
Ruled by: Lhesh Haruuc Shaarat’kor
Droaam: A new fledgling nation of monsters ruled by three hags
Known for: monstrous mercenaries Besesh’k ore, strange magic
Ruled by: Daughters of Sora Kell
Eldeen Reaches: Woods of western Aundair that became independent during the war
Known for: Agriculture, animal husbandry, druidic magic, stone circles, shifters, fey
Ruled by: Different druid circles overseen by high druid Oalian a tree
Lhazaar Principalities: Loose confederacy of pirate lords, merchant princes and sea barons
Known for: Fish, mercenaries, pirates, ships, trade, independence
Ruled by: Each principality rules itself.
Mror Holds: Ancient holds of the dwarves, that became independent during the last war, brimming with gold and artifacts
Known for: Banking, dwarves, metalwork, jewels, ancient daelkyr artifacts
Ruled by: Loose confederacy with an Iron Council
Q’Barra : young frontier jungle nation sitting next to ancient empires of the lizardfolk and dragonborn
Known for: Eberron dragonshards, rare herbs and woods, lizardfolk, dragonborn, frontier living, ruins
Ruled by: King Sebastes ir’Kesslan, Cold Sun Federation and Poison Dusk (lizardfolk) Ka’rashan (dragonborn)
Talenta Plains: Home of dinosaur riding nomadic halfling clans
Known for: Dinoaurs, halflings, livestock, fey, spirits of the land, tribes, ancient ruins
Ruled by: None
Valenar: Steppe land taken over by Tairnadal elvish mercenaries and their ancestor worship during the last war
Known for: Elves, horses, mercenaries, cavalry, raiders, ancestor spirits, double-bladed scimitar
Ruled by: High King Sharas Vadalia
Zilargo: Homeland of the gnomes full of knowledge, library and conspiracies
Known for: Alchemy, Education, elemental binding, entertainment, newspapers, gnomes, espionage
Ruled by: The triumvirate
Demon Wastes; Wasteland of lava, fiends and primordial ruins
Known for: Fiends, Pestilence, orcs, tieflings
Inhabited by: Carrion Tribes, who are a savage people worshipping the archfiends,
The Ghaash’Kala: A tribe of orcs and half-orcs devoted to containing the evils of the demon wastes
Shadow Marches: Fetid swamp filled with the remnants of the daelkyr conflict
Known for: Eberron dragonshards, rare herbs, Gatekeeper druids, daelkyr influence
Aerenal: Massive island populated by the high elves. Good undead walk the streets and the elves wish to become great enough to live on after death as an undead as part of the Undying Court.
Argonnessen: Home of the ancient dragons and barbarian tribes, hardly anyone that visits returns to tell the tale.
Sarlona: Continent and ancient home of the humans. Now ruled by the Empire of Riedra which is opposed by the mountain refuge of Adar of the Kalashtar. Outsiders normally aren’t welcome
Xen’drik: Ancient home of the now destroyed giant empire. Warped by magic and unpredictable
Faiths of Eberron
Sovereign Host: Biggest religion in Khovaire, believed to be the embodiment of all that is good in the world, very diverse deities that can have different names, all can be worshiped or only one, don’t have a hierarchical structure
They are: Arawai – Light and Love, Aureon – Knowledge and Law, Balinor - Horn and Hunt, Boldrei – Hall and Hearth, Dol Arrah – Sun and Wisdom in War; Dol Dorn – Strength and War; Kol Korran – World and Wealth; Ollandra – Feast and Fortune; Onatar – Fire and Forge;
Dark Six: Shadows of the Sovereign Host, opposite side of the same coin, worshipped but mostly in secret, often devoted to a single member of Dark Six. It is believed that they are kin to the Sovereign Host but turned or got banished for their actions.
The Devourer – Destructive Nature and Savagery in Beasts; The Keeper – Greed and Undead; The Fury – Passion, Revenge and Despair; The Mockery – Treachery and Terror; The Shadow – Dark Knowledge and Ambition; The Traveler – Chaos and Change
Church of the Silver Flame: Religion built around the Silver Flame and the legend of Tara Miron. Less a god and more a source of power. Big on fighting evil such as undead, lycanthropes, defined structure with military might in the form of templars, sometimes overzealous. There are other faiths based on the silver flame.
Blood of Vol: Believing that death is the end, the gods are not good, all we have is each other and that true divinity lies within, founded in Aerenal and was popular in Karrnath during the war. Using undead as tools is alright with them and they wish to reach divinity, some become undead to guide others.
Cults of the Dragon Below: Describes various cults that worship the archfiends and/or the daelkyr and wish to free them. Often based on madness and power hungry, Believe that when these powers are freed they will be spared and granted power. Secret cults often hunted down
Spirits of the Past: The Tairnadal elves of Valenar believe that the spirits of champions are your ancestors can live on through the living and one of them lives on in you. You must emulate the deeds of this ancestor and achieve great deeds of your own
Undying Court: The wisest and greatest members of the high elves are preserved after death becoming good undead fuelled by positive energy and the devotion of the living elves. This Undying Court has power and the living elves honour the past and wish to become eternal through their deeds. They hunt down evil undead.
Dragonmarks and dragonmarked houses
Dragonmarks are mystic symbols on the bodies of certain people granting them special arcane powers in certain fields. Many believe that they are tied to the mystical draconic prophecy. It is impossible to buy or develop one consciously. They run in specific bloodlines, so called dragonmarked houses. Those who possess a dragonmark are a part of the house and trained by them and symbolized by the prefix d’ Infront of a name for example Cadan d’Orien.
Due their power they have become titans of industry similar to megacorporations. In the past the united power of the Kingdom of Galifar held them in check but after the war they no nation dares to cross them. They are ubiquitous, you don’t go to a temple for healing, you go to a Jorasco healing house and many taverns are led by house Ghallanda.
The twelve dragonmarked houses are:
Mark of Detection: House Medani
Gives powers of perception and investigation. Often working as bodyguards and inquisitives
Mark of Finding: House Tharashk
Gives powers of perception and finding. Often working as bounty hunters, inquisitives and prospectors
Mark of Handling: House Vadalis
Grants power over beasts. Often working in animal farming and animal breeding
Mark of Hospitality: House Ghallanda
Gives powers that help provide good service. Often working as shop and tavern owners.
Mark of Healing: House Jorasco
Gives power of healing both magical and mundane. Often working as healers
Mark of Making: House Cannith
Gives powers over making and creation. Often working as engineers, architects, factories.
Mark of Passage: House Orien
Grants power over transportation. Often working in the postal service, lightning train, carriages
Mark of Scribing: House Sivis
Gives power over communication both written and spoken. Working with long distance-communication, notaries, interpreters, lawyers
Mark of Sentinel: House Deneith
Gives powers of protection. Working as mercenaries, bodyguards, law enforcement
Mark of Shadow: House Phiralan and Thuranni
Grants power over illusions and shadow. Works officially as entertainment, unofficially as espionage (Phiralan) or assassination (Thuranni)
Mark of Storm: House Lyrandar
Grants power over the weather. Works for weather control, airships, ships
Mark of Warding: House Kundarak
Grants power over warding. Working as locksmiths, security specialists, banks, sometimes prisons.