Here’s the background of the map which is in the following post. TL;DR at the end.
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Interdimensional travel has been discovered in tens of thousands... no, hundreds of thousands... no, millions of universes. And they all think they’re the first.
And they always screw up their first trip.
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In the Year of Our Lord 2030, the United Kingdom of England and Pictland was in a tough situation. At war with the Khalifate of All Ottomania, who had occupied the UK’s allies Castilla and Portucal, its economy was strained, and its military had seen heavy losses. In November, the Ottomans began an invasion of the United Kingdom’s very own territory.
It was pointless to try and fight back. The Ottoman menace had destroyed all Christian nations in the Old World. Their army, consisting of soldiers recruited all throughout the Islamic world, from places like Granada to places like Khandesh, was unstoppable. Their airships were deadly and efficient war-machines, and their navy was an unstoppable wood-and-iron wall.
But the United Kingdom still had hope.
On the 14th of November, Constantine Churchill, General of the 1st Army, and 80,000 soldiers prepared to enter the Portal, an experimental device to travel through time and space--essentially, a time machine. The United Kingdom planned to destroy the Ottoman Khalifate back when it was a small Beylik in northwestern Anatolia.
“Time target set,” announced a voice. The announcer was the inventor of the machine.
“Portal to open in five...”
“...four...”
“...three...”
“...two...”
“...one...”
The Portal created a fierce, fiery-looking orb whose appearance could only be described as the eye of Hell. But it was actually cold, and perfectly safe to go through.
The troops and General Churchill had been educated about the Portal and they knew that this was a safe thing to do. So they walked calmly into the maelstrom.
It took about 20 minutes for all of the soldiers to make it through the Portal. Once the last man stepped through, the Portal simply disappeared.
Were they stranded?
No, it seemed, as a few minutes after its disappearance, it reappeared. The King, John XVI von Habsburg, the entirety of Parliament, the Prime Minister George Washington, and about 500 ordinary civilians exited from the wormhole, the civilians running frantically and tripping over each other. As the 500th civilian passed through the Portal, the Portal abrupty closed and ripped him in half.
After a few minutes had passed and everyone had calmed down, the Prime Minister walked up to the General.
“I have news to share with you,” said the Prime Minister to the General, but directed toward everyone, “And it’s bad news. We will never get back to England.”
He continued, “Two days after you travelled back in time, the Ottomans announced to us that they had created ‘a weapon more powerful than any ever before’. An atomic bomb. They launched one first at Devon. Then at Oxford. Then finally our radar detected a gigantic bomber airship over Norfolk. It was almost certainly the carrier of an atomic bomb. So Parliament, the King, and I set the Portal to about half an hour after the date you were all sent to, and we entered it to escape to safety. And some civilians tagged along,” said the Prime Minister, pointing at the crowd.
“The reason that poor man was ripped apart by the Portal is because Norfolk was nuked and destroyed right that second. And the United Kingdom is being invaded by the Ottomans. And... we’re never getting back.”
But the English had not just travelled back in time. They had travelled to an alternate universe. A universe that was recipient to dozens of accidental interdimensional transfers. The planet Earth in particular had also received, and would continue to receive, a multitude of visits from alien beings
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By 97 A.P. (After Portal), the English had conquered a large chunk of the Balkans and Anatolia. In 85, King John VIII of England-in-exile declared himself Emperor John I of the Anglo-Byzantiumite Empire.
The Anglo-Byzantiumite Empire was already a very multiethnic one. In the east were the Turks. In Greece and the very coast of Anatolia were... well, Greeks, except for in Peloponnesus. There lived Jewish Spaniards who had immigrated to the Empire seeking freedom--which they did get, by serving as mercenaries for the Imperial army. In the far northwest were Croats, and in the milder northwest, north of Greece, lived Serbs. Semi-Slavic Greeks who called themselves Mackedonians lived in the area called Mackedonia, and Bulgarians lived to the northeast of them and north of the capital. In the northernmost reaches of the Empire lived Wallo-Bulgs, Bulgarians who spoke a Romance language. Lastly, English people lived in the center of the empire and all throughout as administrators. As time passed, English spread outward from the capital and spread down the social classes. Eventually the ethnic groups called the Anglo-Bulgarians, Anglo-Byzantiumites, Anglo-Romans, and Anglo-Turks would appear, all speaking English, all practicing some aspects of English culture, and all having some English ancestry; however, they kept regional peculiarities that differentiated them.
Starting 100 A.P., a series of... ‘visits’ (strandings, really) would occur, which would vastly increase the amount of ethnicities in and around the Empire... non-human ethnicities. Some of which lived underwater around the Empire.
The first ‘visit’ was that of the Jupitorians. Jupitorians are insectoid alien beings: tall and skinny, they have four legs positioned nearly-upright but facing slightly outward from their body, two arms, large multi-lensed eyes, and large mandibles. In 54 B.P. (Before Portal), the great King Zz’klvang of the Jupitorian Empire, which possessed four systems on the other side of the galaxy and had its capital at the city of Jupitoria Ga-Ztzt on the planet Juptioria, commissioned an expedition to the Far Side--our side. 154 years later, the members of that expedition woke up from their cryogenic sleep to discover that the back half of their ship had been completely destroyed in a massive explosion that, if the airlocks in the ship’s middle and front had not contained it, might have destroyed the rest of the ship as well. Their vessel was in the proximity of a blue planet and tumbled down, with most of the thrusters gone. It crashed into the area called Serbia in 100 A.P, killing and displacing many Serbs to the south, who eventually adopted some Greek customs.
The second ‘visit’ was done by the Martians. In an alternate universe, Mars was colonized by humanity in the 2300s. Mars was ‘halfway terraformed’ as many called it, in the process of being shaped like Earth since the 2060s, with air that was breathable for several hours (after which you’d have to go back into base and receive regular air), many lakes, grass, some trees, many research bases and terraforming bases, and a large completely-terraformed dome called New America with a full ecosystem and a city called New Washington. In all, the population of Mars was 10,000, with most of them residing in New Washington. In 2385, however, an amphibious alien race who the humans called the ‘Ghosts’ invaded the solar system... or, well, they tried. A gigantic weapon, called Goliath, that orbited the Earth and had previously protected it from an asteroid impact in 2130, destroyed their ship. But within the Ghosts’ ship was a core that contained a light speed core, interdimensional core, a hyperintelligent AI that controlled the ship, and the high-ranking military officers who commanded the ship before its destruction. The core survived. Too small to be targeted by the Goliath superweapon, it rocketed towards the planet Mars and crashed into New America, breaking it. Simultaneously, the cracked New America dome as well as half of Mars was transported to the alternate universe of the Anglo-Byzantiumites.
This had rather dangerous consequences for the citizens of New America, and not just the fact that the Ghosts’ ship’s core crashed into the city. Half of the planet Mars was transported along with the remnants of the dome, but the rest of Mars was completely barren and... Martian. The atmosphere was rapidly equalizing. Therefore the Martians used the spacecraft that remained to escape to Earth. Unfortunately, only 1,000 Martians could be accommodated, even stuffing each spacecraft to the absolute limit. The 9,000 Martians remaining on Mars dug underground tunnels and tried to bring whatever they could salvage from the surface underground. A new, much smaller, dome was built to keep the air in, and the oxygen scrubbers and atmospheric generators sustained said air. Perhaps 8,000 Martians died, but it is thought that Martians still survive today, restricted to their small dome. Meanwhile the 1,000 Martians who headed towards Earth were granted a surprise. The Ghosts, in the frantic retreat underground, made themselves hidden somewhere, perhaps in a Martian lake. After the last of the Martian spacecrafts had exited the atmosphere of Mars, the Ghosts’ ship’s core launched into space and followed the fleet of refugees. When the Martian ships were in close proximity to Earth, the core shot most of them down. The largest of the ones that were not shot down made a strategic shot at the core disabling it and sending it tumbling down to Earth. In 104 A.P., the Ghosts crashed into the Adriatic and most of the Martians crashed in southern Hungary and northern Bosnia. The Ghosts made their home under the sea and built up quite a reputation for fierceness. The Martians became loyal subjects of the Anglo-Byzantiumites and intermingled with the Bulgars and Croats. A new hybrid people emerged, called the Martio-Bulgars, and they soon became the Jupo-Martio-Bulgars after adopting the language of the Jupitorians.
The third ‘visit’ was by the Galactanteans, a culture composed of the Atlantean, Galactan, Norisian, and Vultraxian alien races, as well as the enslaved Plutonians. Each of the peoples mentioned evolved on the same world, Galactantis, except for the Plutonians, who derived from Galactantia’s moon Ux. All of the peoples mentioned also dwelled underwater. In 80 A.P., President Yb Ougivdzk of the Galactantean Empire deported a group of political opponents, as well as slaves that had participated in a revolt, into space, course set for the Galactantean system’s sun. This band of misfits, however, managed to gain control of their ship and save themselves. Returning to Galactantis was obviously not an option, so they voyaged into deep space in hope of finding a watery world to settle. They arrived upon Earth--or Water, as they called it. As Galactanteans preferred to live in bodies of water between landmasses, they chose the Mediterranean to settle. And they prospered in their united ‘underwater empire’. Well, not completely united, for a small group of Vultraxians headed south and split ties with the Galactanteans, and the Plutonian slaves all escaped to the east. By 120 A.P., the various Galactantean peoples had spread to the areas they now live in.
The fourth ‘visit’ was by the Automatons. In one alternate universe, the human race became gradually more and more addicted to cybernetic augmentation--by 2140, the average human was 95% artificial.
In the universe of the Automatons, interdimensional travel was invented in 2150. A group of ten automatons tested it for the first time in November that year. However, in a situation similar to that of the Anglo-Byzantiumites, their world fell to nuclear war soon after their travel through time, space, and universe. As a result they never made their way back, but formed a sphere of influence in western Anatolia and became the subjects of the Anglo-Byzantiumites.
The last ‘visit’ was by the Neptunian Fish-Race. Since time immemorial, there has been an interdimensional gate under the Black Sea. Until 130 A.P., it had not been activated since the extinction of the dinosaurs. And starting late 130 A.P. and ending 132 A.P., it, activated, emitting strange finned creatures from their dimension’s version of the planet Neptune. Since the closing of the Portal, the Fish-Race, split into the Neptomarians and Neptopiscians, Neptunian ethnicities differing slightly in appearance and majorly in culture and religion, has been infighting with itself so much that it has not set foot on... or, rather, placed fin into the waters of, any body of water other than the Black Sea.
Now it is 300 A.P. The Anglo-Byzantiumite Empire is more backwards than you’d expect for an empire founded by interdimensional travellers and populated half by peoples and aliens from space. Of course, all of said travellers and all of said aliens were small in number when first arriving. And time leads to the forgetting of old ways.
TL;DR
Alternate UK was being invaded by an alternate Ottoman Empire in a world similar to World War Two, but with the Ottomans instead of the Nazis conquering Europe. The Brits sent people back in time to destroy the Ottoman Empire when it was still tiny, but they actually sent them to an alternate universe--an alternate universe that almost all interdimensional travellers from any universe end up in. The Brits form an Anglo-Byzantiumite Empire and soon receive a multitude of alien visits.
The Martians are human colonists from an alternate universe’s Mars who arrived along with the Ghosts. The Galactanteans and their sub-ethnicities (which includes the Plutonians) are from a faraway planet.
The Jupo-Martio-Bulgars are actually genetically just Martio-Bulgars.
The Automatons are technically cyborgs.
The Fish-Race of Neptune are self-explanatory. They are fishlike beings from an alternate universe’s Neptune.