PMD: Delvers of Abyss

Surface:

• Relic Town is the main surface location in the setting. It's located around the rim of the Abyss, on the Mystery Continent between the Air and Grass Continents. (Map not to scale.)
  
• Generally, the surface is in the early stages of a magitech-industrial revolution. The tech level advances as one gets closer to the Abyss - Relic Town has limited electric lighting, fully functional plumbing, and perhaps even early radio communication - but the surface is universally in the pre-transitor era.

Delver's Quarter and the Delver's Association:

• The Delver's Quarter refers to the area of the city right up next to the edge of the Abyss, which has markets, inns, appraisers, and other services catering mostly to Delvers. It's also where one can find most Guild Halls, the Headquarters of the Delver's Association, and all public and private Steam Elevators.
• The Delver's Association is the de-facto regulatory body for anyone looking to explore the Abyss, formed to help make doing so safer. Primarily, they help to organize rescue missions for any mon that go missing in the Abyss, and subsidize (portions of) the rewards for these rescue requests. They also handle postal service from (but not into) the depths, and operate public job boards that any mon is able to take from or add to.
• In exchange for additional oversight and a portion of their income from jobs and relics, Abyss-exploring members of the Delver's Association are entitled to guild-provided room and board and discounts on certain in-network appraisers and shopkeepers, among other benefits.
• Steam Elevators are the primary way that most people descend into the Abyss - unless you or a friend have some way to fly, of course - providing service between Relic Town and various points in the First Stratum. The Delver's Association provides public Steam Elevator service for a very minor fee, and some guilds might have private elevators of their own.
• Anyone entering the Abyss legally is required to have a valid, properly functioning exploration badge. They serve not only as a means of identification, but also an imprecise tracking mechanism and a 'panic button' teleport back to the surface (without any equipment or relics the user might have collected).
• The Delver's Association sells basic, but shoddy badges for cheap (doesn't need to be purchased through the CYOA to have at the start), or one can join up with one of the city's guilds for access to more stable ones with better features, in addition to other perks (does need to be purchased through the CYOA to have at the start). (Badge Examples need to be updated (eventually))

Abyss:

• The Abyss is a giant hole several kilometers wide, and of an unknown depth, that exhibits certain properties consistent with those of a Mystery Dungeon.
• One of the primary draws of the Abyss are Relics, strange tools with abilities which exceed what most Pokémon can do naturally or scientifically.
• This is hardly the only reason someone might delve, however: training, categorizing the unique ecosystems that have developed down below, or even just the prospects of exploring the largest known Mystery Dungeon in the world also bring many to Relic Town.
• On occasion, non-feral Pokémon - ones who almost always say they weren't Pokémon 'before' - end up just appearing on some Stratum of the dungeon.
• Instead of a traditional floor structure, the Abyss is divided into several biomes/strata, separated by barriers that make it difficult to simply fly all the way down. The deepest anyone has reached at this point is the 10th stratum, but common consensus holds that there are far more.
• Delvers have reported that, with some exceptions, almost every stratum is lit up with a daylight cycle mirroring that of the surface, even when they have descended far enough that the sky isn't visible.
• The Abyss contains dangerous 'feral' Pokémon who would like nothing more than to exsanguinate any delver unfortunate enough to cross their path. They get stronger the deeper one delves. Like in all dungeons, the origins of these enemies are debated: some say that they are formed out of the memories of everyone who has ever entered, and others that they are merely autonomous constructs created by the dungeon for its own protection, for example.
• Also like a traditional Mystery Dungeon, strata of the Abyss randomize themselves. This can take about a month for more stable sections, to almost hourly for less stable ones, but it almost always happens when no one is looking at a particular patch of the dungeon. Tests done on the first stratum have revealed that mon-made structures remain intact, but are otherwise also subject to this randomization phenomenon.

First Stratum: Tiny Woods
The First Stratum of the Abyss is known as the Tiny Woods. An apt name for an excellent place to start one's adventure. It's made up of small, sparse forests - decently open but still covering almost all of the stratum's area - situated on shelves of various size and altitude. These shelves tend to be connected enough that there isn't too much trouble descending from one to the next, although it's made all the easier for anyone with the proper equipment or anatomy. Water features such as lakes and rivers tend to be decently common throughout the forest, and all sorts of berries grow in this stratum as well.
Barrier: No barrier separates the First Stratum from the surface. Just be sure to choose a good landing spot.
Common Types: [Bug], [Grass], [Water]

Second Stratum: Petrified Forest
Go deep enough, and the air starts to tingle with static. The trees lose their leaves, before becoming bone-dry and stone-hard. Scrubby plant-life still grows, but the entire area has a desolate look to it. The Second Stratum is known as the Petrified Forest, and it is a fair bit more dangerous than the first. Both because its denizens are more powerful themselves, and because they tend to know moves that will paralyze an unwary delver to leave them trapped against further onslaughts. A steady supply of cherri berries are well recommended for anyone passing through.
Barrier: Electrical storms are common in the open air between the First and Second Strata. They're not too difficult to evade, but they will deliver a nasty shock to any flier (and passengers) unlucky enough to be caught in them, paralyzing enough that they could be in serious danger of crashing to the ground.
Common Types: [Rock], [Electric], and Pokémon with Paralyzing moves.

Third Stratum: Eroded Desert
Even further down, rock gives way to sand. The colossal plates of the First and Second Strata even out into arid, rolling dunes on the third. This is the Eroded Desert. The dunes are pockmarked with occasional caves and ruins badly decayed by the progression of time. Lack of water is a primary concern for anyone coming this far, for there are no easy sources like there were above.
Barrier: A massive sandstorm blocks visibility between the Second Stratum and the Third. It's far more all-encompassing than the electrical storms above the Second Stratum, and thus far more difficult to avoid.
Common Types: [Ground], [Fire], [Flying]