Disclaimer: I own nothing that you may recognize.
AN: In this chapter I try and explain where Wizards and Witches come from and how the two universes are actually one, you will see some familiar characters, and don't hate because of Mordred being the same age as Arthur, and not his son.
I also added a war between the factions which will more commonly be known as the great war, but what stopped it instead of the death of god, was the death of all but four seraphim, and the death of the four Satans who had started the War, not the original plot but hope it is an okay substitute.
Immediately following Khan's departure the faction leaders did as he asked before going their separate ways in hopes to rebuild and recover. After a few centuries, the church that followed Khan and the Angels once more became the most dominant, as the other factions slowly became more and more distant from Midgard. About a four hundred years after the war ended, followers of Khan started to attack any who held power they claimed to be of the devil, which in fact were primarily innocents, holders of sacred gears, or magi, though occasionally devils would be killed. The mass deaths of Magi, however, caused that faction to work to defend themselves. Four such Magi, who also happened to be wielders of powered swords decided that part of this would include the creation of a school and fortress that would be able to hide magi, who had since started calling themselves witches and wizards, and to educate younger magi on how to control their powers. These four magi, whose names were Godric Gryffindor, Salazar Slytherin, Rowena Ravenclaw, and Helga Hufflepuff, called their school Hogwarts.
For the first two or so decades, Hogwarts was a place of peace and a stronghold that held back all foes of the Magi, when strife began in the school especially between Godric and Salazar. However before things escalated too far four new students of exceptional power appeared at the school and each seemed to embody the traits of a founder, these students Merlin Emrys, Arthur Pendragon, Mordred Raodragon, and Morgana La Fey were the greatest students the founders could ever hope to have and brought peace again to the castle which lasted decades after the four students had left.
This peace, however, was not to last, thirty years after the four students left the school war broke out, as the Dragons that had been residing in Arthur and Mordred decided to make their appearance and continue their fight from centuries before. This war broke the founders as they took sides, with Salazar and Rowena siding with Mordred with his red dragon and Morgana, their prize pupils, while Helga and Godric sided with Arthur with his white dragon and Merlin. After decades of fighting Azazel, the newest Lucifer, the fourth since the war against Trihexa despite the fact that Lilith was still alive she had simply chosen to give up her position after a century, Micheal came to stop the war and perhaps gain a new member of their households. However by the time of their arrival, it was too late, Merlin had taken Excalibur and thrust it into Mordred's chest as he divided Godric's power to that of a small infant, which due to his large stature caused his heart to give out. As this happened Arthur too was killed by Salazar who used the demon sword Dáinsleif to freeze his blood, as Arthur had just beheaded Rowena. Having witnessed these events the three decided that since Micheal was the oldest of them he would be the one to make an invitation.
"Greetings, magi, I am Micheal and these are my companions Vortigern Lucifer, and Azazel, and we had hoped to welcome you into our ranks as angels, devils, or fallen angels, depending on your desires, what say you?" Micheal asked calmly before being shocked as Salazar walked over to him before spitting in his face.
"Oh, that's rich, the leader of the people who have hunted down our kind for well over a century wants to welcome us into heaven, I say fuck off," Salazar said coldly as Merlin walked over to Vortigern, as the others nodded their agreement with his statement.
"Well isn't this funny, the man who believed that I was a devil child is the devil himself, I must say that despite my hatred for Salazar I agree with him, fuck off," Merlin said coldly as he raised Godric's sword, which Michael recognized as the holy sword Ascalon which Zeus had used to kill the Heavenly dragons, to attack Vortigern, only for Azazel to pull out his own sword and deflect the swing.
"Micheal, it appears we are not welcome here, it would likely be in our best interest that we depart before we start a war between the Magi and the other factions when we just barely managed to regain peace after a two hundred year war between factions," Azazel said firmly.
"Very well, perhaps we shall find other magi who are more willing to join our forces elsewhere," Michael said after Vortigern nodded his head in agreement with Azazel.
"Not if we have anything to do about it, we shall protect our own from your filth, and cause it so they can only be found if they leave the areas of our protection, or the wards are broken," Merlin said coldly before going and walking away from the battlefield as the three leaders returned to their own domains.
In the decades that followed the four remaining studied and searched until as Helga's health began to fail they managed to create a ward-scheme that would do as Merlin Promised, making all magi invisible to all the other factions, which included regular humans, unless they either sought them out or the wards were broken. Choosing the base the wards around Hogwarts already nearly impenetrable wards, with the ward being tied to the life of the basilisk that Salazar had recently hatched since basilisks were immortal beings, and to a ward stone hidden in Rowena's secret room for hidden things. To seal the wards Helga and Salazar gave their lives, which were already near their close, to ensure that the wards would be stronger than any other wards ever created, and making it so the only way the ward stone could be destroyed was with fresh basilisk venom from Salazar's basilisk, or by use of Fiendfyre.
The construction of these wards had an effect that none of the four would have imagined since every faction loved bringing Magi into their ranks. This coupled with the fact that no one would accept blame for the vanishing of an entire species lead to a war between the various factions broke out, unlike any seen since days of Satan. In this war, every faction fought against every other faction, which led to the complete extinction of a few of the smaller pantheons such as the Olmec. In time, however, the smaller factions removed themselves from the war that continued to rage between the three oldest factions, until only they remained. Then seeing there was no means of a decisive victory Azazel, Shemhazai and Baraqiel decided to pull the fallen angels' factions from the war, which continued on between the devils and angels. 400 years after the fighting began Michael and the other three archangels looked and saw that they were the sole surviving Seraphim, while the devils saw that the nearly extinct houses now were completely gone, and those houses remaining were now numbering in the tens instead of thousands, and so under new leadership, the Four Satans who had started the war having been killed, the last two factions settled into a delicate peace, to wait and watch until they could once more have Magi on their side.
In the centuries that followed, all of the main factions tried to create pseudo-Magi, with the Devils creating the Magicians, the Fallen creating the Mages, and the Angels creating the Clerics, who were soon deemed too unstable and gotten rid of, however, none of the groups was able to create a race who could focus magic that originated from within, like Chaos had all those centuries beforehand.
While these wars took place, centuries passed and the wards of the four held strong and grew as students went to Hogwarts and used magic, the excess of which feeding the wards, until the wards grew to surround the entire world, only being breached twice the first of which was 500 years after the wards had been set three brothers came across Osiris, who gave them three sacred gears in hopes to break the wards. These sacred gears in time would become known as the deathly hallows as due to the wards they did not pass by the soul but from one had to another in part due to their great power. The first of these gears was eventually called the death stick when the term the master wand would be more fitting, as it doubled the powers of the wielder, including animagus forms not that any would realize this, but this boost was lost if the wielder was bested in a fight where the gear would change loyalties to the new master. The second gear, called the resurrection stone, though summoning stone would be a better term as it could summon spirits from the Void. The final and perhaps most powerful gear was the invisibility cloak, which could completely hide the wielder from any and all beings.
The second breach happened in the late 1800s when a young Albus Dumbledore was searching the world for knowledge and came across a passage about an extinct firebird called a phoenix, and so sought to find one and in so doing was able to let a high ranking member of the Phenex clan, called Fawkes, through the wards, however, he was unable to escape back to the underworld and so chose to wait and see what this Magi would do and if he could help in bringing down these wards that had frustrated the factions since its inception.