Welcome to the "ABYSS". A natural pit that has existed since the beginning of time. No one knows how the pit came to be, nor the world beyond the pit for the seas surrounding it are filled with monstrous behemoths and raging storms. The different societies of the abyss live on its outskirts, forming a massive ring of a city where there is no end, centre, or beginning. The abyss is separated into "levels", as the citizens of the abyss call it. Each level its own biome, offering seemingly endless resources for those that dwell above. The abyss is filled with dangerous creatures and hazardous environments. Each succeeding level sees a significant increase in danger, therefore resources are mainly gathered from the top few levels. No one knows how deep the levels go, and only the bravest and the best of adventurers dare venture into the depths below.
Dungeons & Dragons 5th Edition (DnD5e)
Level 1 lies just a few short kilometers below Level 0. Yet, it is as if the two are on entirely different worlds. Level 1, due to the Gaia Force Field, has its own enclosed atmosphere and environment. Even its climate is independent to that of Level 1.
Level 0 is the surface level of the abyss. It is also where the population of the nation of Abyss resides.