This is a one-shot AU retelling of the story of Kingdom Hearts, the χ-Blade and the Keyblade War from the Kingdom Hearts series, with some mixture of The Legend of Korra(more specifically, Book 2) into it.
Notes: I do not owned Kingdom Hearts or The Legend of Korra, both belong to Disney/Square Enix and Nickelodeon respectively.
Long ago, in the age of fairy tales, the world was filled with light, gifted by Kingdom Hearts, protected by the legendary χ-Blade.
Many desired the light and sought for it. Others renowned and worshiped it for its power, wisdom and the birth of mankind.
However, many who hunger the power of Kingdom Hearts became blinded by hunger itself.
Their greed, jealousy and newborn sins to obtain such sacredly introduced darkness to the world.
In order to control Kingdom Hearts, they forged powerful weapons in the image of the χ-Blade.
The Keyblades.
Some served the light, some served the darkness, some sought balance, while others sought for power.
Together they clashed and by ten thousand years since Kingdom Hearts and the world came into being, they bought upon the Keyblade War, an ancient and devastating conflict that eventually embroiled those who did not desired Kingdom Hearts and took the lives of thousands.
Eventually, the light faded and darkness overwhelmed, the lives of almost every countless Keyblade bearer taken, a war that was perhaps all for nothing.
The χ-Blade witness the great conflict, but it was too much to handle and the legendary weapon was eventually shattered.
The power and essence that tied together with Kingdom Hearts and the world split into two entities…
Raava, the great spirit of light, the embodiment of light remaining in the hearts of many, the birth of hope, and the new generation's crafter of Keyblades.
Vaatu, the great spirit of darkness, the embodiment of the darkness in many, the seed of destruction, and the maker of creatures borne from the sins of mankind's hearts, the Heartless.
The broken remnants of the χ-Blade that were connected along with Raava and Vaatu became twenty pieces: seven fragments of lights and thirteen shards of darkness, were scattered to parts unknown.
As of Kingdom Hearts, it vanished, disappeared, trapped in the deepest darkness.
The world itself crumbled from the darkness, but the lights remaining within the children and the innocence restored back what which was destroyed, but as worlds with their own hearts and individuality, separated from each other.
That very day that signals the end of the war, and the destruction that brought the greatest change it left behind was what the ancients referred as… Harmonic Convergence.
A symbolism for the ancient war that took away thousands, or perhaps a punishment bestow upon mankind for their lust for Kingdom Hearts and bringing about the war, the spirits clashed and fought on the day of Harmonic Convergence, on every ten thousand years to determine the fate of all worlds.
Raava would provide Keyblades she crafted with the essence of Kingdom Hearts, bestowing them to the ones she subconsciously chosen for the sake of defending the very light remaining in the worlds. However, what path the Keyblade wielders of this new era took is what their hearts told them to, and she had no right to enforced her own will to theirs.
Vaatu corrupts the hearts that had left beings, transforming them from the darkness within them into Heartless, instinctual creatures of the dark that seek for nothing more but to consume the hearts of others to create more of their kins, and the hearts of the worlds to plunged them into darkness.
Should Raava prove victory, all worlds remains safe and protected in their respective Realms.
Should Vaatu prove victory, all worlds would be doomed shrouded and overtaken by the Realm of Darkness.
The conflict between Raava and Vaatu was never-ending; even if their opposing spirits destroys them, they will continue to reborn within them every ten thousand years: thanking the pieces of light and darkness splintered from the χ-Blade.
As they were both created from the χ-Blade, the twenty pieces of light and darkness anchors their life, respectively. Without them, they are nothing more than godly-like mortals opened to their permanent dismissed.
However, while the light of the sun can create a shadow, light too cannot simply exist without the pitch of darkness.
As much as how mankind feared of the darkness overwhelming the entirety of all worlds for ten thousand years, should Vaatu or even every thirteen shards of darkness be permanently destroyed, the χ-Blade cannot be reforged and Kingdom Hearts will forever remain shrouded within the darkness.
Unreached… perhaps, for eternity.
A/N: This is my first fanfic, so fair criticism accepted. I may probably rewrite it…