Cosmology
There was a time that nothing existed. Nothing except Dan, the supreme being of all there is, and his children, those that later were named Overlords
And there came a time that Dan thought to create a world. And so he created the multiverse of Shadowmere: universes separated one from the other like water is always separated from oil. He then gave over the world to his children and named them Overlords; and said to them they were to reign over the multiverse and create on the universes and decide everything for them. And then he stepped down to see the wonderful work that he was certain his children would do.
And the Overlords named the universes. The first one ever created they named after their father; Dan was to be the greatest and most populated universe from all of them. After that they went on to name the rest of the universes of the creation. And they named them Sera and Hadro and Trood and Uno and Valhalla. It was not until much later that they decided to create themselves a new universe for the kingdoms' rulers from other universes to wage game wars, the one that was named ElysianField.
The next step was to make life and evolve it. After they were done, great numbers of races existed. Many were eradicated during the very first millenniums or even eons of their existence. Others prevailed or just survived; the first ones managed to even gather in societies, small at first but growing greater while time passed by, until the first kingdoms were made. After an age of great wars and massacres, strife and chaos, the overlords decided to set rules for kingdoms in the world of Shadowmere. They also decided that only certain races could congregate in kingdoms - why they chose the ones they did remains unknown ever since. Magic was too a weird realm back then; powerful, uncontrollable in some cases, enabling some to achieve unbelievable feats and leaving others unable to use it effectively at all. So the Overlords changed the magic in Shadowmere, resulting for it to be more balanced and stable.
Then they set a limit on the number of attacks allowed against a kingdom for a specific period of time, unless it has attacked first so it can be hit back that many times in retaliation always, in the same time block; military attacks, raids, assassinations, looting and spells with destructive results on the target were set to be considered attacks for that matter. Next came the rules for alliances, as many were forged soon after the first battles between kingdoms. Each alliance was allowed a place for the member kingdoms' rulers to gather and discuss important issues since, its grounds belonging to the alliance as a whole.
The Overlords finally decided that they would "reset" the kingdoms after some time elapsed from the last creation of kingdoms as they will, in periods named Ages. The kingdoms would be wiped out from existence, their land becoming part of the unknown lands again, only the capital and it's inhabitants of each kingdom surviving the "cleansing", along with the closest associates and royal guard of the ruler. Alliance grounds would also remain untouched during the Ages.
Rulers of the kingdoms would become immortals by the Overlords if they wished, not aging as ages pass by, and would be also be spared in the end of every Age of the universe. The only exceptions to the non-aging are undead rulers, as they do not age anyway. Of course the rulers can be killed normally - they just don't age anymore - gaining immortality only in age. The Overlords also forbade to rulers from actively participating in battles between their kingdoms, as some posses power that can turn the tides of battle in their favor. They are only allowed to order the attacks but not interfere with the commanders of the army on the battle field. Last but not least, they also forbade to them ruling more than one kingdom. The only universe in which they allowed rulers to own more than one kingdoms was Trood.
Mages are not allowed to cast fireballs, lightning bolts and other offensive spells in a battle between kingdoms as the Overlords decided after they changed magic during the ancient times. They can just cast defensive or enhancing spells on the kingdom and their comrades in battle to aid them in combat. They also are allowed to help in covert operations, though they have to do it by casting spells on the troops and staying in the kingdom concentrating to maintain their magics while the thieves and assassins slip into the enemy lands. All these restrictions came from Dan's children because mages in a battle can easily turn the tide with no more but a small lucky striking of a destructive spell.
The rules for the Open Market of each universe changed many times before resulting to the current ones. In contrast with the past when one could trade goods in the Open Market for other goods, the Overlords finally decided that everything should be sold for gold. The only thing that remained the same from the creation of the Open Market in ancient times is that when a kingdom purchases troops of another race, they revert to the race of the kingdom that buys them, no matter their original race. Similar changes are applied to weapons, armors and warmachines, so that they are adapted to the race of the buyers in order to be used properly.
In the universe of Dan they decided to allow the existence of Deities, powerful beings that would be worshipped and gain power from the numbers of their followers to interact with the kingdoms of the mortal world. It was much, much later that they allowed Deities in Hadro as well. Of course, deities would be confined by rules too. The temples in their name are taken down from all the kingdoms at the end of an Age, and a big new one has to be build again in the capital to allow a deity to draw mana from that kingdom in the new age. In addition, a Deity cannot cast more than three spells on a specific kingdom in a time period, equal to the one that restrains the number of attacks on a kingdom.
An important fact about each universe is that they were created with some realms existing in each one of them aside their main part, like parallel dimensions attached onto them, but part of them whatsoever. Examples are the Hell in Dan, ruled by Demon Lord and populated by demons and the Celestial Fields in Trood, home of benevolent powerful creatures referred to as Celestials. Realms with the same name and nature also exist in different universes as well, like one Hell in Dan and one in Hadro, both populated by demons. The realms Underworld and Heaven in specific exist in all the universes.
Due to the existence of magic, the creation of portals between the main universe and its realms is possible, and so is the marching of great armies via dimensional portals from both sides. That's why the Overlords forbade this kind of acts from the very first time they became a possibility.
During the recent Ages, the Overlords have been changing some of the rules for some universes, but most of them contiunue to be the same that they were. They also created the new universe of Sunki.
So far the Overlords rule the multiverse of Shadowmere with wisdom and determination, while the Great Dan is watching the glorious work of his children without interfering. And he has decided that this is how it is going to be for all eternity...
By Doom.