According to ancient legends, Hell and the Abyss were actually akin to the Emerald Dream, being mirror blueprints of the work of the ancient gods.
It's just that the Emerald Dream was the only successful blueprint that connected with the real material plane, teeming with life and thriving with all things, an idealized world. It was a world that only souls and creatures that controlled nightmares could enter.
Hell and the Abyss, on the other hand, were composed of countless failed blueprints; they were unsuccessful creations.
