Great Maelstrom

In Sin-Eater society the Great Maelstrom is an eschaton event, much akin to the Biblical 'Deluge' story. It is the end time for all Bound where the immense Death Energy residing within the Great Below is suddenly relinquished and thrust upon wholly to The Underworld, before quickly swallowing it all again, erasing everything in its path, and with it, all Ephemeral beings.

Overview
The Great Maelstrom is a scarcely know legend, mentioned only three times yet in ancient texts. No living nor dead creature, not even the Kerberoi yet discovered are aware of such an event. Those who have heard of this event merely regard it as a boogeyman to The Bound, who are easily startled. The only authenticity the legend has for itself that the three mentions of it are much too consistent with each other to be a mere coincidence, but the sheer time span and large distance between their apparent creation makes it impossible to have been any kind of collaborative work.

The texts are warnings of the Mortal Coils becoming too thin between The Underworld and the Mortal World. Described as "Twilight has grown into Night". Many of the events from the texts say the Great Maelstrom is to reset the natural order between Death and Life, so humanity would not be forced to travel the world without rest. They accurately describe The Bargain, psychics and many Domains of The Underworld. Bar from one location that has become a Sin-Eater joke. The Lost City of Stygia, which functions as the final catalyst for the Great Maelstrom, and is said to foster the most powerful ghosts to have ever exist. Most of the Pharaohs, with the latest mixture even being the legendary King Arthur as well. Beings of such immense power that if the Great Maelstrom would swallow them, they could eradicate the whole Underworld just through overwhelming presence alone. Sin-Eaters may not believe in such legends for various reasons. Maybe out of the bliss of ignorance, as they would rather not have this doomsday sword hanging above their head at all times. Others simply don't see any evidence of either The Great Below to have any capability to spew out anything from itself as it seemingly functions a gigantic black hole for ghosts. While others point to the fact that countless Bound struck up to try and find The Lost City of Stygia, just to come home without any evidence or progress towards finding it. For all intents and purposes, this mythical event is merely a folklore of a bygone paranoid era.

The Books of Storm
"'Don't look into the eye of the storm. You may not like what you witness.' - Carl Jefferson"The texts found describing the Great Maelstrom became known as the Books of Storm. None of them were ever in one place at once as they are all owned by different krewes. Though most of them don't give it much validity, they are still mighty Mementos of grandiose power. One few can ignore.
 * Tutankhamun's Book of the Dead - Describes the Great Maelstrom in morbid detail, how it works and where exactly it will come from, where it will travel and what it will do. It describes meticulously as well how to prevent it, as well as detailing how to even reach The Lost City of Stygia. However, following its instructions towards Stygia did not lead anywhere. The book is under the possession of Hecate's Pride.
 * The Sapphire Tablets of Ur - Describes the extinction events of all Bound and how Great Maelstrom was forced into existence. Explaining that the appearance of psychics being the first sign of the Coils becoming too thin, lending the powers of the dead to the living accidentally, and how abmortal beings cause The Underworld to becoming tangible towards mortals. The book is under the possession of Creed of Seers.
 * The Varaha Purana - Describes the aftermaths of the Great Maelstrom, the reshaping events of The Underworld and how everything will in time change. It focuses mainly on the changes of both Coils, as humanity will fall into an age of faithlessness, where The Underworld will form anew. The bok is under the possession of The Avatars.