"The layers of the Abyss were created by Demos and Gorgos, in their panicked drive to put as much distance as possible between Set and the Nexus of Chaos. While the structure of the Abyss was their doing, the powers that flooded in to occupy that structure are infinitely varied in form, motivation, and origin.
"Some layers of the Abyss were occupied by eldar bent on chaos, such as the Jade God. Many more were filled with dark dreams of Set's slumber that were given form, potency, and even sentience by the merest echoes of his thought. Sages argue over whether Lolth began as one of those incarnate dreams, or was truly an eldar in her own right.
"Other layers have been claimed by mortals seeking a certain brand of power and immortality, liches and demon worshippers who stake out entire Abyssal worlds like homesteaders landing on a new continent. There they hope to hoard secret knowledge and dark magic while they dodge death, far from the warm gaze of the Creator.
"Being a place of infinite variety, the countless layers of the Abyss are not uniformly horrible. I have seen many places in the 'upper' planes of the Abyss that the mortal reader would probably find relatively pleasant. In fact, if not for slightly unpredictable weather and a higher incidence of birth deformity, some of them would be hard to distinguish from Tehra.
"On planes such as these, untold billions of souls rise and perish, unaware that they are even living in an Abyssal realm. I saw one world where every single god worshipped - and there were hundreds - was a facet of the multiple personality of the single, nameless demonic entity who held that plane under its sway.
"When I was first shown these worlds by Corth K'Ven, the immediate effect was to chill me to the core. My first thought was to wonder if I, and everyone else in the world I knew, was not laboring in some Abyssal insect farm like those countless masses, knowing nothing of the true nature of my existence. I felt sick, and for a few moments I questioned everything I thought I knew. Corth expected this would be my reaction, and when he saw the shock on my face, it was the first time I ever saw him smile.
"What brought me back was my faith in Pha Rann. I remembered the times in my life that I had felt His approval. I remembered the many times I had felt the direct touch of His power, through the ministrations of his priests and paladins. And I decided that if those things were not real, then I was deceived, but the possibility was so remote that it could safely be disregarded.
"I believe Lord Corth could see most of these thoughts as they played across my face, and to my surprise, he appeared pleased at my swift recovery. I think he enjoyed challenging my beliefs, but would have been disappointed if my faith had not been equal to the knowledge he had just shared with me."
Sage Alaura, Commentaries on the Nexi