Koto: Legends Arise/Religious Myths
Mythos of Creation
In the beginning there was Musubi, the Hitorigami or lone goddess. She existed before the Planes, when there was only darkness in the multiverse. Musubi wandered the darkness for an innumerable amount of time, until in her loneliness she gathered parts of the darkness together and created a companion; Yomi.
Finally, being with company, Musubi continued to create, and crafted the Material Plane from her right eye. On it she created, vegetation and animals. She then crafted the races of the world, each endowed with strengths and weaknesses so that they would strive and fall as they saw fit.
She was proud of her creation and tried to share her joy with Yomi. Alas, Yomi was made from darkness, and like the void that created him, he only knew how to consume. He preyed on the inhabitants of the Material Plane, growing fat from their life sources, until many races were driven to extinction.
Horrified by Yomi's gluttony, Musubi tore Yomi into shreds and scattered his body into the darkness. Then, to try to amend for the lost life she created the Spirit World (Feywild) from her left eye and the spirits of the fallen creatures took refuge there, where their descendants still remain. The scattered parts of Yomi soon gathered to create a similar plane, the Shattered Realm (Shadowfell) which continues to draw on the life force of the Material Plane to this day.
And so the denizens of the Spirit Realm are longer lived than those from the Material Plane, as they experience less influence from the Shattered Realm... or so they say.
Mythos of Sun and Moon
After Musubi had finished crying for her lost companion, she turned down to earth and saw its inhabitants were cold and scared. To keep them warm and protected, Musubi crafted the goddess Izayoi from the brightest stones of the Spirit World, and tasked her with watching over the Material World.
However, Izayoi was a vain goddess, and instead of keeping constant watch, she created a palace for herself above the Material Plane he called Takamagahara (Mount Celestia) and hid away.
Angered by Izayoi's action Musubi crafted the goddess Hirume out of the warm heart of the Material Plane. Hirume drove Izayoi out of Takamagahara into the darkness, and let her glory spread to light up the Material Plane. However, when she sleeps, Izayoi attempts to return to Takamagahara, wandering across the sky to find it.
And so the Sun rises during the day when Hirume is awake and vigilant, and when she falls a sleep, the Moon creeps across the heavens as Izayoi attempts to return to her lost home... or so they say.