Pandemonium

all souls used to go to "heaven" a land in the sky where souls could rest and be happy until they decided to go through life again and reincarnate. but some got restless in their afterlife wishing to be reborn but didnt want to worry about losing their status in the afterlife, so they created cults among the living focusing on different ways around this issue

There were Two cults

The cult of the covenant:

(make deals to become gods and never leave heaven)

A pyramid structured group of cultists that each were required to worship those above them in a complicated system that created ascended gods of various powers, they declared war on the gods in an attempt to dethrone them, they are the only mortal group credited with making Qiggok bleed. Once they lost this war a new realm was created to punish them Pandemonium a multi layered realm of punishment, a mockery of their pyramid system, each with its own punishments.

THE CULT OF the beast

(become strong enough that you'll never die, and never leave the mortal plane)

This cult was more secretive than the cult of the covenent and was formed from the reminenants of the original cult, this daughter cult abandoned the form of its predessor instead vying for "might is right" known for a few things, Firstly you earned your spot not by agreements and manouvering but by killing your competitors, soon they began to realise the limitations of their forms and recalled the stories of the unbridled chaos that was thefeywilds before the creation of the Archfey, the powerful hybrid animals used in battle against the other seasons, remembering the season that was, the flood and how it no longer exists they realised in the past the power of the hybrids helped destroy forever something the gods had made. So they began to experiment with various hybrid forms to give them advantages against their soon to be fellow demons, this cult grew quickly and would likely have not attempted to destroy the gods were it not for a few rogue Balor who could not best each other as they equalled each other in power. They soon had decided they must be the most powerful beings and gathered whichever beings would listen, however demons are not loyal beings, loose lips spilled plans and in the fighting that followed It became obvious that the gods were ready and there was a traitor that had told the gods of their betrayal. The demons were thrown into pandemonium for their betrayal and were laughed at by the previous members of their mother cult who had at least made the gods bleed. The demons declared rivalry on the devils and they have been feuding ever since.

Then was created Limbo, to hold the spirits of the dead  for 100 years until they would be reborn (or sent to pandemonium to be punished, or the heavens to be rewarded in rare exceptions, however most are reincarnated.) but the world was a wild palce and the grand city was filled to overflowing