As a world continue floating in chaos with the darkness of Erebus protecting and shielding it. A broken soul protected by a weapon that looked like a wheel shot into the world. It seem that the broken wheel is protecting it's master and shielding it from Erebus.
The broken soul traveled across the world looking for a body that fits it before accidentally going into the underworld. It was there that it found Hades the god of the underwolrd. Perhaps due to it being broken, the soul couldn't detect the danger causing it to try and seize the body of the god of the underworld.
And as expected it failed. Due to it being too weak, it failed to seize the body of Hades, guving Hades a chance to devour the soul.
It was then that Hades gain the memory of Azrael the necromenser and the mastery of his artefact.
Hades "These memories....this power... who am I ?Azrael ? Hades ? Am I azrael ???
No...nO...NO. I am HADES THE GOD OF THE UNDERWORLD. How interesting, a soul from another world...."
Azrael the necromencer. A being born from the body of the most powerfull warrior and the soul of the strongest dark wizard in his world. Azrael was a born necromencer due to it's body being technically dead while having wisdom comparable to gods. With it's ability, Azrael started his journey of killing and transforming people into his subjects. He became so powerfull that the the ten most powerfull wizard in his world who are all enemies with each other, worked together to destroy him.
They were so powerfull when working together that Azrael had to escape into the underworld of that world. It was there that it found the most beutifull thing he ever saw, reincarnation. He watched as souls came and bath in the water of reincarnation, forgetting their past and reincarnating to a new being.
He was so touched that he decided to make reincarnation his own. So as he stayed and use his power to conquer soul that have yet to reincarnate into his subject. He created a kingdom of the dead in his world. Since then anyone who died in that world can no longer reincarnated and can only become subjects of his kingdom.
This act angered the world causing the world to cultivate strong beings to try and destroy him. And it did, twelve heroes were born and came to the underworld where they fought a great battle with Azrael. And they nearly won if Azrael have not tried to explode reincarnation using a weapon he have called the wheel of the dead.
The explosion of reincarnation killed the twelve heroes. And interestingly the wheel that Azrael use to explode reincarnation manage to absorb the laws of reincarnation and biught the broken soul of reincarnation to escape the world.
If they didn't go to the underworld and try to seize seize Hadea body, maybe they would become a powerfull god.
Hades "Well now it's all mine. And I have to say Azrael is quite stupid. Instead of taking reincarnation for himself, he should've try to control it. After all would never let him disturb the cycle of reincarnation. If his world doesn't already have a reincarnatuon maybe the world would let him continue his kingdom of the dead as the resting place of the dead. But with reincarnation the world would never do that. After all every soul and wisdom born in the world cost the world, world origin. And with the existence of reincarnation, the world no longer need to condence souls anymore, instead it can recyecle the existing souls into new souls."
"Hmm maybe I can create my own reaincarnation in this world. I can absorb the concept of reincarnation into the underword. And it will be easy to do so... I can just intergrate the wheel of the dead from Azrael into the underworld. After all the wheel have been bath in the laws of reincarnation causing it to have the ability to reincarnate souls"
"YES THAT'S IT !!! I will make the river styx into a pathway leading into the center of the underworld where souls can reincarnate. Now all I need is to find a way to wipe the memories of these souls before reincarnating them"
As Hades continued thinking of how to make these souls forget their live, he remembered a certain god, Mnemosyne the goddess of memories. One of the Titan goddess that Zeus seduce to help him defeat Kronos. He also remembered one of his subordinate, Charon the boatman of the styx who was a god born by Nyx and Erubus but doesn't have a priesthood.
It was then that he made the decision to kill Mnemosyne who was loyal to Zeus and give her priesthood to Charon. However, it seem that he has to find a way to kill her in the underworld to have the chance of retaining the memory priesthood before it disappear into the world.
And with that decision, he went to Nyx for her help. And after he told her of his plan to give Charon, her son a priesthood and that he will owe her favor for doing it even if it failed, she agreed.
With Nyx help, Hades manage to trick Mnemosyne into the underworld by asking Nyx to give visions that Mnemosye will become more powerfull by going into the underworld.
And as Mnemosyne step into the river of styx. Thanatos use his chains to trap her while Hynos make her fall asleep. They then bought her to Hades who switfly killed her.
He took out her priesthood and gave it to Charon. Then he buried her body in the river of styx to make the river strionger sibce the body of a god is a very good tonic for the world.
He also cut her divine personality that represent the god of memories and gave it to Charon to make him have an easier time to devout the memory priesthood. While the rest of it was destroyed.
He also sealed her divine soul into a gem since he wanted to experiment on what would happen if he reincarnate the soul of a god.
And as he finnish sealing mnemosyne into the gem. Charon finnished devouring the memory priesthood. Becoming the god of memories. Since then there is a legend of a boatman named Charon who lead the soul of the dead on a journey with his boat where they will forget their life before sending them to reincarnation.