Rulos's Dark Abyss
A tale often told to children of the western hemisphere, Rulos's Dark Abyss is a place where all who commit misdeeds go for an untold amount of time. The length you remain in the lightless void often is said to be proportional to your act - if you stole something to be greedy, it might be shorter than killing someone, being deceitful, etc.
Though largely based on the teachings of the Keepers of the Three (specifically Rulos, obviously), the use of it is wider-spread than just people who follow the religion. Parents often tell their children to always act as if Rulos is watching them, because if they commit any kind of foul deed to suit themselves, Rulos will remember it when they have grown old and ready for death. Upon dying, he will take them and hold them over his cold abyss, recounting their crimes. Then, he throws them inside. Once a long enough time has passed relative to their crimes, he will retrieve them, and instruct them that they will be reborn, and to commit no crimes to his teachings in the new life. If they do so again, they will be placed in the lowest part of the abyss as soon as they think about doing wrong. Sometimes, if the crime is severe enough, he will snatch them up from where they stand, and immediately place them in the abyss.
Historians have found that, though different now through semantic change and other changes due to it's largely oral telling, it stays very close to the written account of Zathiah (one of the three siblings that founded the Keepers of the Three) and the dream he had in which Rulos spoke to him. In the dream, Zathiah wrote that Rulos held him between the two realms of the Eternal Fields and the Dark Abyss, and told him that only those pure of heart and mind could enter the Eternal Fields, or be reborn again into what they desired. Should anyone be placed in the Dark Abyss, they would stay there until their sentence ended, and then be reborn into a similar life to prove themselves changed.
This tale has spread fairly rapidly throughout western Folterra in it's history. Within the first forty years of the founding of the Keepers, the tales had already spread throughout all of Naea, and partway into Telra. Within the century, it spread all the way into Telra, and into Arlyia, and Arcadia. From here, it slowed until the 10th century, where many people cast off the idolatry of the Keepers (or became less pious), but spread eastward into Irongate, western Ilysia, and Aldren, and then halted until current time. Voldrym, Choria, Plenn, Lahas, Araj, the Shaded Isle, and Moongrin all revile the teachings of the Keepers, and as such, do not tell this tale to their children.
Variations & Mutation
Some societies in Telra have altered the base story to claim that Rulos will snatch you immediately after you commit any selfish act, and place you in the abyss for an extended amount of time, sometimes indefinitely with no chance of proving yourself or rebirth. While the Keeper's religion is newer to the area, some towns in Aldren also have altered it to say that Rulos will give you a horrible deformity upon your release, letting all know that you were selfish and harmful. Other regions wishing to distance themselves have even altered it to change to a different deity, but keep the same premise intact.
In current times, this teaching is mostly regarded as a tale for children, though some hold it much more dearly than that. In Telra, Naea, and Arcadia, a large majority of non-formally religious (that is, they still hold beliefs, just not full worship) people still tell this tale to their children in order to get them to behave, as well as a few of the lesser-strict tales from Heyera's scripture. Those who do find themselves devout to the Keepers regard this not as a children's tale, but as a strict moral code to follow to the grave.
There have been several spin-offs of this tale, and even one major play that the Children of Rulos find closest to the original writings of Zathiah, and widely praise.
Several artists have given their ideas as to what the tale is truly like - there are paintings and murals dedicated to it, especially so at the temple of Rulos.