Disclaimer: Everything I said in the first chapter applies to this as well.
A brief review of the history of the realms- 00
Long ago, long long ago, before the House of Dowe had any influence over Earthrealm, or any of the other realms for that matter, long long long long ago, there was a great war. Well, not so much of a war as a great battle. And there were no soldiers or armies or sides, even the divisions of good and evil were very vague. But there was a great battle that was to decide the fate of the whole universe. The beautiful prophet Delia had foreseen the event, and her husband Argus, a powerful god and protector of the realm of Edenia, had sacrificed his sons to a great quest that would save us all.
The quest had failed, horribly, and as the very fabrics that kept the universe stable began to weaken, the Elder Gods finally intervened. A seemingly unthinkable kombatant from earthrealm was chosen as the herald of the gods. Oddly enough, his own vanity and arrogance over the years was what shielded him from the taint of hatred, deception, and chaos that had left a stain on all his comrades. His being chosen amongst other worthy candidates is still debated amongst philosophers and monks. But how the message is delivered is of little importance, the actual message itself was what brought the aftermath of armageddon to a swift end.
It is said that years after the battle with Blaze, when Taven, son of Argus, failed to subdue the kombatants, John the Herald sent out a call that echoed throughout all the realms and the people came in fear and love and awe and terror towards the voice that spoke through the mortal. He damned those people, for it was through their own pride and ignorance and greed and lust that they had brought armageddon upon themselves. New rules and divisions were given throughout the realms, and new punishments would be put into affect for those who dare to question or violate the orders of the Elder Gods. No longer would they stand idly by and let the fate of all existence be left in the hands of fools. The war between the forces of dark and light had come to a stalemate with a stern warning from the heavens "You are being watched."
Not all present were pleased with the message. Shinnok, the disgraced former Elder God, was the first to question the orders given by John the Herald. Keeping to their word, the Elder Gods brought down their wrath in all its power upon Shinnok. Before the eyes of those around him Shinnok was struck down with a dark force that sent his whole being into a state of non-existence. No longer would the Elder Gods be merciful in their punishment, no longer would those who defile the ordinance of the Gods be stripped of their powers or banished to the lowest of realms. The Elder Gods had learned from their past mistakes and they were now determined never to let them be repeated. Too much was at stake to risk a repeat of the events of armageddon, and everyone present seemed to learn their lesson.
And so as shady alliances ended, bridges were built or burnt, forgiveness given where due, and even lives restored through one means or another, life returned to as it was and as it always will be. The realms of Chaos and Order will always feud. Outworld will always strive for control over the other realms, though strict sanctions had been placed on their ability to possess sovereignty over realms as well as the realms ability to regain their independence, and Shao Khan was in no position to question the decisions of the Elder Gods after they graciously reinstated him as ruler of Outworld.
In the years since John the Herald came with his message and left, and before events that brought the existence of Caelestis to the known realms, there have been three Mortal Kombat tournaments, one through which Hotaru had lost control of the walled city of Lie Chen, he returned to Seido seemingly unfazed by the loss. Another saw the final liberation of Edenia from Shao Khan's control.
But there was one thing that worried the Elder Gods more than anything. The barriers between the realms had been weakened greatly. If left unchecked, gateways could open between dimensions in places where they should not be. This problem of course could only be healed in time, and the chances of a portal opening to a realm unknown by the Elder Gods themselves would be improbable, and that what would most likely happen would be that a portal linking one of the six realms to another would occur, this would still be an event that the Elder Gods would have liked to avoid and resolve as soon as possible if need be.
And so, as decreed by John the Herald, after the divine intervention of the Elder Gods brought peace to the realms, an order to the guardians of all respected realms that if they were to discover a gateway, destroy it. It would take a millennia before the universe would heal itself on its own, and it was up to the very people who caused it's near destruction in the first place to make sure the status quo was maintained at any cost. This concludes your brief review of the history of the realms.