It is uncertain how this cult came into existence. All that is known, is that around 490 NCE, an unnamed elderly Nikiltan discussed spirituality with a travelling Hashhaltu. The official Scrollkeeper explanation has it that this conversation was muddled by mistranslations and poor communication, and that the old man had a troubled mind in the first place; in either case, the nikiltan got insight into forbidden knowledge, and founded a cult to honour it.
He had been granted contact with the Effaced, a mythical being from before Aeruvartix's time. This entity wanted nothing more than to be forgotten by mortal men, so that it'd have no more ties to the material world.