AN: I've done a little rewriting and editing so that's why things will seem different.
When the universe was young, two worlds formed side by side by the names of Gaia and Gehenna, more commonly known today as the Earth and the Ghost Zone. While it has long been widely accepted that the Earth has a sentience and caring personality, often lovingly referred to as Mother Nature, very few have realized that the Ghost Zone is just as alive and caring.
Gaia's realm was a physical place composed mostly of soil and water, being a rich place that would easily host a vast and diverse ecosystem for all sorts of life. Gahanna's realm in contrast was more metaphysical, consisting of very few random floating formations but rich in ectoplasmic energy that would be shaped by things like thoughts and emotions into many unique and wonderous beings.
Gaia was the first to have true creatures and planets grow within her realm and roam across her surface, being the mother of all life. But as with all living things, their time comes to an end and their body dies and their souls pass on to what comes after. Some of those that had passed found their way into Gehenna's realm and began a second life, an afterlife if you will. Gehenna watched over the beginnings of her realm with these first spirits though they were few and rudimentary as they came from simple animals. The few human souls that found their way into her realm were welcomed by Gehenna with open arms and she took care of them as if they were her children.
Soon though Gehenna was overjoyed as beings unique to her own realm began to form as well, formed from the growing thoughts and emotions flowing from the links between the realms. These were the first of her children and they had lots of potential and power, eventually known as the Ancients to her other children as newer generations continued to appear.
Gaia and Gehenna continued to grow side by side, their realms often intertwining and supporting each other. Lost souls of Gaia's departed children who weren't ready to truly rest would wander into Gehenna's care and would be given a second chance, a way to overcome their regrets and fix their mistakes before passing to what lay beyond. As civilizations and cultures grew on Earth, so too did they grow in the Ghost Zone. Mass dreams and myths from the growing human race took form and Gehenna breathed life into them. Their great power was used to benefit both worlds.
Gaia's and Gehenna's control over their realms was absolute, yet they did not use the great power they possessed to rule over and dictate their children's lives. Instead, they would let their children grow and learn on their own, giving gentle guidance and inspiration as needed. On rare occasions, Gaia and Gehenna would take on a more physical form to walk among their children. Many did not realize who they were for only those who truly believed were in tune enough to recognize just who was in their midst. And those whose disbelief was too great would not even see them and would scoff at their claims even if they could. Still, Gaia and Gehenna loved all their children and only would act in their best interests, whether or not they realized it.
All was not perfect though, for both humans and ghosts are flawed. There were those who cared only for their own selfish desires or became corrupted by the power they had. There were tensions and conflicts, loss and sorrow, as all sorts of tragedies that befell upon both worlds. And yet, there was still happiness, kindness, and growth. The two worlds grew stronger and close together with children from both sides intermingling and creating lasting bonds that easily crossed the veil between worlds. Still, Gaia and Gehenna did not interfere whether during times of great joy or great sorrow, but watched over it all, subtly guiding their children to a better future.
But then a wicked King by the name of Pariah Dark rose to power within Gehenna's realm. He was merciless and desired to conquer both worlds, having the power necessary to do so. He wreaked havoc all across Gehenna's realm, turning large portions of the beautiful realm back to the barren wasteland it once was. Gehenna watched it happen with great sorrow and knew it would not be long before the destruction would spill over into her sister's realm. Gaia and Gehenna could not allow that to happen, so with great sorrow and a tearful goodbye, they sealed the links between the worlds and severed the strong connection the worlds shared, leaving only enough ties that both worlds remained stable. Despaired for the loss of her sister, Gehenna focused on a way to end Pariah Dark's cruel reign. She reached out to her first children, the Ancients, and gave them the strength they needed to seal Pariah Dark away, though she knew it would not be forever.
Years passed and Gehenna's realm began to recover and heal from all the destruction and life began to flourish once more, her children coming out of hiding to rebuild and their civilizations prospering. Gehenna continued to guide her children and provided strength and comfort to them, giving them hope that the future would be better. When her realm was finally stable and growing, Gehenna reached out to Gaia and began to carefully build the connections between them that had been severed for so long.
Even more years had passed and the bridge between the two worlds was a lot stronger though still far from being complete, the process needing to take time so as not to overwhelm the balance between realms. Unfortunately, a new problem had arisen that had called Gehenna's attention. It seemed during the time that the worlds were separated, humanity had forgotten what ghosts truly were and had begun to fear them. They sought to drive them away and sometimes even end them permanently. This in turn led several of her children to be more aggressive and allowed the dark souls to wreak havoc on the Earth, leading into a vicious downward spiral.
Gehenna pondered constantly on how to resolve the issue without interfering herself. She spent many days trying to find a way to fix everything and she would often talk to her eldest children for advice as she could not yet contact Gaia. Though her children did not have a solution, they were encouraging and hopeful that one would appear in time.
Surprisingly, the solution came unexpectedly one day in the form of a 14-year-old boy.