Help with my setting, The Vents.

[Pictogram]

Ideas/critiques for my setting

Hi everyone, I’ve recently got back into dming 5e and I’m having a blast. One of the players is a friend of mine and the others are randos I met through discord, but I must say, I feel extremely lucky as they are engaged, thoughtful, and like to role play.

I sort of had a vague idea for this setting that just sort of sparked in my mind. I don’t have everything flushed out by any-means but I wanted to share what I had and get some feed back/ ideas on the setting.

All of the player characters hail from nations that had a summit, and at this summit among other things, they discussed a location of the world called The Vents. The Vents is a massive drained oceans made into a valley, the depth of this ocean was great so the cliffs are huge and it’s several hundred miles to get to the sea bed proper. The Vents are extremely hot, filled with a constant steam that fills the air from geysers and (once) underwater volcanos. Extreme weather occurs in The Vents like soot storms, acid rain, and treacherous wind.
I wanted to make the denizens of The Vents very hardened by the land and give it a bit of a frontier feel with overtones of the primordial. The gods in the vents are different from the “abovers” ( what the people of The Vents call those from up above their valley) as they are just features of this majestic drained sea, like the cliff sides, resting mineral springs, earthquakes, etc. I’ve been having fun interpreting how the different races would survive down here and adapt.

The party has been tasked with establishing contact and learn about the Vents as they are unmapped and little is known about them in the nations up above. They found out that these 9 major cities have these communication devices called whisperfires, but 1 month ago before the party arrived to The Vents a great earthquake happened knocking much into chaos in The Vents, disconnecting the whisperfires. Creatures born of the elements have been whispered fantastical powers by a god sleeping in the earth, driving some mad with new power, towns are in recovery mode, change is on the horizon. So far the party has secured one whisperfire at the first town the came across, scaling down the cliff side ( which was in the thralls of mass agitation from a salt and steam mephit that kept two feuding groups hot under the collar with their new found power) and are now at the second town, which is a gnomish/ dwarven town. It’s called Progenitor, and it’s a mechanized city that can scale the sides of the cliff but has been too damaged to move by the great earthquake, and is currently going through some racial tensions as one of the main ruling dwarven family’s wants to abandon the mechanized city ( along with the gnomes) and tunnel into the cliff proper. The party is currently investigating the ruins of a destroyed part of the city, overrun by burrowing beasts,trying to find the whisper fire there.

Sorry for the info dump but I guess I wanted a sketch of the things happening right now and translate a feel for things. Does anyone have any cool ideas for the setting or storyline? Any ideas for the 7 other towns and how the fantastical people have adapted there or are currently going through it because of the current catastrophe. Any ideas for monsters, items, or Magic’s that would be unique to this hot land?

[VoxRationis]

There used to be an ocean several hundred miles deep, but now there isn't? Where did the water go? Is there any left for the rest of the world? If other nations continue to have water, what stops the Vents from filling back up again?

[Pictogram]

There used to be an ocean several hundred miles deep, but now there isn't? Where did the water go? Is there any left for the rest of the world? If other nations continue to have water, what stops the Vents from filling back up again?

I'm thinking that the Vents was an ocean passage that connected 2 oceans, something happened ( not sure what) but has physically blocked it off from a shifting of the earth from the other oceans. What drained it, I'm not completely sure yet. But yes, the rest of the world would still have other oceans/water and such.

[VoxRationis]

So what about drainage from adjacent landmasses? Has that been redirected, or is it insufficient due to local topography to overcome evaporation? What about rainstorms blowing in? (I'm also a little concerned about the air pressure differences at the bottom of a hole several hundred miles deep, but that's a quibble rather more easily dispensed with in a fantasy setting than the questions of drainage.) Where did all that water go? Has it transferred somewhere else on the planet, causing a staggering increase in sea levels, or has it disappeared into some sort of underground portal? (Perhaps it went to the Plane of Fire, locally flooding much of it to devastating effect, and some of the steam--and displaced mephit refugees--has come back through the portal.)

How long ago did this ocean drain? You said the setting has a frontier feel, so I presume it was relatively recent. How quickly did it drain? How are there already major settlements at the bottom? What drives people to come here, particularly in significant numbers, overcoming such a massive impediment as these cliffs? What gods are down here? If they predate the draining, have they been having trouble with the environmental shift (and presumably the deaths of most of their followers)?

Is a construct like Progenitor typical of the technology level in your setting? How would something like that be manufactured? Where does it get the energy for moving? I don't know the math on how much energy it would take to make a city not only move, but climb against gravity, but it's got to be at least ten times more difficult than powering a carrier through the water, which suggests it's got to have the equivalent of several nuclear reactors' worth of power generation. If this scale of engineering* is not typical of your setting, why are these dwarves and gnomes so much more advanced than the rest of the setting? Why have they applied these energies to a clambering city and not more typical pursuits (even something like transit infrastructure leading to the surface and a regular city in the Vents)?

Ultimately, a lot of the questions I have spring from your stated line that the former ocean was several hundred miles deep. On Earth, that's significantly thicker than the crust and a small but significant fraction of the Earth's diameter; once drained, the Vents would appear from space as a dent in the curve of the planet akin to the firing dish on the Death Star. I don't know how large your world is, but it's still difficult to fathom that such a cavity could exist without the pressure from the rest of the crust, to say nothing of the mantle, filling it in. Were I you, I would change the scope of the depression to "several miles," which would continue to be impressive but be more believable.


*Which, to be clear, is probably beyond the level of modern Earth civilization; we've never had cause to build anything like that, so it's difficult to say definitively that we couldn't if we put our minds to it, but I'm doubtful that we could.

[sktarq]

Er....
I'm going to assume that we are going for a low fidelity world as compression heating alone would make it uninhabitable otherwise.
Look at the history of the Mediterranean when that dried out a while back. Which could give you lots of ideas in general actually. With mountain ranges acting as islands of habitable territory etc.

And while the "hundred miles deep" sounds a bit OTT a couple miles would do it.

Questions of "why go here" would seem to be a big step as well.

[the_david]

And while the "hundred miles deep" sounds a bit OTT a couple miles would do it.

Yeah, the deepest point on the Earth is the Mariana trench, and that's less than 7 miles below sea level. The lowest point that's not underwater is the dead sea (Which is a lake.) at 1412 ft. below sea level. The highest point above sea water is mount Everest at 5 and a half miles. That's a difference in elevation of less than 13 miles, or 6 miles if you don't want to drown.

You can chalk this up to "fantasy writers don't understand time/science fiction writers don't understand distance." It happens a lot, and that's okay. It is what it is.

One thing I've had in my head for years is the Vredefort crater. It's the biggest impact crater in the world with a diameter of 190 miles. Unfortunately it has eroded a lot in the past 4 million years. I'd love to know the approximate elevation levels it used to have, because such a place would make an awesome mini setting.

[Laserlight]

I assume you mean that it's several hundred miles travel from the previous coastline to the new coastline? Rather than the sea level having fallen by that much, which would be implausible.

The Mediterranean (probably) dried out during the Messinian Salinity Crisis. When a channel reopened from the Atlantic near what is now Gibraltar, there was the Zanclean Flood. What was left was (probably) a few saline lakes, fairly steep walls all around what is more or less the current Med coastline, and deep canyons cut by the Nile, Rhone, and a couple other rivers.

"Down in the Bottomlands" is a novella written by Harry Turtledove, takes place in an alternative history in which the point of divergence occurs 5.5 million years ago during the Miocene Epoch when the Atlantic Ocean did not reflood the Mediterranean Sea, as it did in our history. You can find it free online.

[Martin Greywolf]

One thing I've had in my head for years is the Vredefort crater. It's the biggest impact crater in the world with a diameter of 190 miles. Unfortunately it has eroded a lot in the past 4 million years. I'd love to know the approximate elevation levels it used to have, because such a place would make an awesome mini setting.

Quick math based off of diameter to depth ratios gives me 34 km depth for Vredefort, which I suspect would swiftly (within a few years) get eroded thanks to gravity and volcanic activity, even if it got that high.

Still, that's plenty enough for isolating a pre-modern culture.

The Mediterranean (probably) dried out during the Messinian Salinity Crisis. When a channel reopened from the Atlantic near what is now Gibraltar, there was the Zanclean Flood. What was left was (probably) a few saline lakes, fairly steep walls all around what is more or less the current Med coastline, and deep canyons cut by the Nile, Rhone, and a couple other rivers.

There's also Doggerland which dried up and then got sunk for certain, although it's not a lot of use for this particular problem.

Does anyone have any cool ideas for the setting or storyline? Any ideas for the 7 other towns and how the fantastical people have adapted there or are currently going through it because of the current catastrophe. Any ideas for monsters, items, or Magic’s that would be unique to this hot land?

Assuming your players are on board with exploration focus, exploring various cities and cultures should be in the center stage. That means it's less about making something wildly exotic and more about making sure the differences are felt everywhere the PCs go.

For example - you have frequent acid rains, so every house in a certain city is coated with molluscs that secrete slime that neutralizes the acid. Mention the mollusks often, have them be a slip hazard on chases on rooftops, have a small subplot where someone is poisoning a bunch of them to ruin their rival.

Another example, ash storms. Everyone wears cloth covering any and all bodily orifices, and taking them off means you're in yor home, safe. Over time, this has evolved into a social custom where "baring your mouth" is considered a sign of trust/closeness. Set this up right, mention it often (in descriptions or as idioms in speech), and someone taking off their mask can be a Big Deal to the players.

[the_david]

Quick math based off of diameter to depth ratios gives me 34 km depth for Vredefort, which I suspect would swiftly (within a few years) get eroded thanks to gravity and volcanic activity, even if it got that high.

Still, that's plenty enough for isolating a pre-modern culture.

The difference in elevation between Mt. Everest and the Mariana trench is less than 20 km. I was thinking more of something like a thousand years after the impact. Enough time for a civilization to rise and fall.

Edit: It was apparently 40 km deep, so that was a pretty good guess.

[brian 333]

Over many generations a tropical coral reef was sculpted by merfolk into a vast underwater citadel. Since its occupants could swim, many primary entrances to large areas are vertical, but the whole city is a 3d maze which was designed to guard the treasury, the throne, and the lineage of the King of the Inner Sea.

Salt zombies and caustic wraiths now guard a kingdom of ghost-mers who have long since forgotten they were once creatures of the sea.

Giant brine shrimp inhabit the salt tarns, swarming and consuming anything organic that falls in their toxic pools, while land crabs of enormous size prowl the wastes looking for their next meal, even if it's another crab.

In the center of the citadel is a fresh water spring in which is hidden The Orb of Water. This orb is invisible in water except for the way it distorts light passing through. It can be used to scry; indeed, it looks and feels like a crystal ball. It can also be used to command water elementals, though it can't summon them. But its greatest secret is that it is now the home of the last King, his queen, and their nine daughters. Placing the orb in the open sea will free them. If the occupants are discovered in their timeless demiplane the king will barter the key to his private treasure vault in exchange for their freedom. Communication can be conducted by scrying into the orb or through planar travel to the demiplane within the globe.

[sktarq]

Okay the more I think about this the more of a tough nut this is worldbuilding wise.

Because you have 3 things. A seemingly incredibly difficult environment, cities, and extreme isolation. Because this is an exploration theme we have to take the ide idea that the "upperworld" knows very little about the vent world region and has minimal if any contact with it...I mean that is what the players are trying to do right?

And this means that all the stuff the goes into making a city has to be built up within the vent lands. Normally if you don't want to worry about skills, materials, etc being sourced somewhere you can just say it was imported. But not here. If the acid rain/ash storms etc make it impossible for trees to grow what to people build stuff with...houses, barstools, kitchen spoons etc. If you can pull off what such replacement would be like it will very much increase the thrill of exploring the lands but it will need LOTS of work. It doesn't sound like they are exporting wierd minerals for lumber at the edge of cliffs from what little you've given us.
And do the same for food, fuel, tooling, clothing etc. You're building a whole economy down there.
Also where did the inhabitants come from and why go to this place when it is obviously not fun or easy and basically a one way trip?

Edit: oh and for using "magic solutions" to much of the above...implies a level of magic in the general world that would render the isolation and need for exploration moot. A couple flying towers may be rare but could probably eventually be spared to take a look. Or such solutions would need to be worked around somehow. Which implies more work not less.

[Eldan]

Quick math based off of diameter to depth ratios gives me 34 km depth for Vredefort, which I suspect would swiftly (within a few years) get eroded thanks to gravity and volcanic activity, even if it got that high.

Still, that's plenty enough for isolating a pre-modern culture.

Article I found online says that it's assumed to have been up to 40km deep, but likely quickly (within years) collapsed to about 10km. Still impressive.

[brian 333]

Okay the more I think about this the more of a tough nut this is worldbuilding wise.

Because you have 3 things. A seemingly incredibly difficult environment, cities, and extreme isolation. Because this is an exploration theme we have to take the ide idea that the "upperworld" knows very little about the vent world region and has minimal if any contact with it...I mean that is what the players are trying to do right?

And this means that all the stuff the goes into making a city has to be built up within the vent lands. Normally if you don't want to worry about skills, materials, etc being sourced somewhere you can just say it was imported. But not here. If the acid rain/ash storms etc make it impossible for trees to grow what to people build stuff with...houses, barstools, kitchen spoons etc. If you can pull off what such replacement would be like it will very much increase the thrill of exploring the lands but it will need LOTS of work. It doesn't sound like they are exporting wierd minerals for lumber at the edge of cliffs from what little you've given us.
And do the same for food, fuel, tooling, clothing etc. You're building a whole economy down there.
Also where did the inhabitants come from and why go to this place when it is obviously not fun or easy and basically a one way trip?

Edit: oh and for using "magic solutions" to much of the above...implies a level of magic in the general world that would render the isolation and need for exploration moot. A couple flying towers may be rare but could probably eventually be spared to take a look. Or such solutions would need to be worked around somehow. Which implies more work not less.

There were islands in the sea on which dwarves, hobgoblins, and other non-aquatic races resided and the environmental, social, and economic upheavals that came with the draining of the oceans forced them out onto the former abyssal plains.

When the volcano at the core of the Aotakark Archipelago exploded the peaceful hobgoblins living on the sheltered sides of the nearby tropical islands had to set out on foot immediately with only what they could carry or risk burial in ash or pyroclastic flows. The agressive ones survived and now they are militant cannibals who have forgotten they were once farmers and traders.

The dwarves and gnomes who lived in and on Gniata'anga were largely unaffected until the forest died from drought and acid rain. Every year they range farther from their ancestral home seeking the materials they need to survive.

The lich Salladi'mamil uses her arsenal of magic to maintain a few square miles of the once vast and anchent forest of Jilliata. The elves who survive there are cowed thralls who live in fear of her mercurial temper and the undead who were once their families and friends who now guard the island from outside intrusion or attempts to flee. The few who fled and were not caught and turned into undead guardians now roam the wastes as savage tribesmen.

The possibilities are endless. This is also fun. I wish I didn't have to go to work so I could do this all day.

[Eldan]

I guess you'd need massive magic to have anything resembling a civilization of most D&D humanoids, since there doesn't seem to be enough sunlight for plants.

Have you thought about nomads? Settings like this always make me think of scavenger nomads. Tribes who use druidic magic (either a priestly caste, or perhaps group rituals) to get their food, and otherwise scavenge to the relics of the local civilizations. They could climb former islands, or perhaps dig through now-exposed and abandoned undersea cities of aquatic civilizations.

Ooh, actually. How about Aboleths? They have magic (or psionics) and you could have some survive in magically protected pools. The destruction of their normal ecosystem could make them desperate enough to start any given plot you want.

[VoxRationis]

Wait, why isn't there enough sunlight? Is all the steam supposed to be significantly thicker than regular cloud cover or something?

[Eldan]

Oh. I guess the OP doesn't mention that. That was just what came into my mind about reading about volcanic soot and deep valleys. Nevermind, then.

[brian 333]

Salt Zombies

As the water receeded, vast pools of saltwater were isolated and dried up to become salt-flats. The unfortunate creatures caught in these sinks were preserved by the salts and animated by the concentrated magic of the lost ocean.

Most of the creatures were aquatic bottom feeders such as octopuses and crustaceans, but in at least one case a sehaugin city was preserved this way, and stories about surviving the attacks of white sailfish and sharks which swim in the sand are too numerous to ignore.

[KragBrightscale]

Love the idea, though the how and why the Vents have not been eroded is tricky. I’ll leave that to others to figure out and focus on potential communities and groups down there:

Previously inhabitable islands dotted the sea before the water level dropped. Fishing villages and prosperous trade hubs that depended on seafaring vessels struggled to adapt to their new circumstances. Faced with this unprecedented disaster, there were different responses:

Spoiler: The Fleet

Show

Some set sail in vast fleets before the water level dropped to far, hoping to escape the coming drought. Alas, their desperate quests was doomed to meet with an insurmountable obstacle.

By the time they approached the edge, the sea level had dropped so far that only steep cliffs could be seen extending into the smoggy sky. Repeated attempts at scaling the rim resulted in failure and casualties. Eventually, these refugees had to make the most of their situation. Their ships became their new home, as the water was now too low to even return to their islands.

Their ancestors’ attempt to flee on their ships has passed down through generations, and now they still organize themselves as small nomadic fleet of vessels. Instead of cutting through water, these vessels designed based on their communities’ original ships, have wheels and are dragged by enormous oversized lizards (or other beasts of burden). Positions of authority are based on naval systems with each fleet ruled by an admiral.

Although fierce warriors that will fight to the death to protect their fleet, they are also some of the few that actually have a reputation as merchants. Others know not to attack or rob these fleets, as if even one gets away, you’ll be the enemy of every fleet in the vents, and no community has survived that yet.

Spoiler: The 2nd wave

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Things got worse after the fleet left and the water level kept falling. The poorest and most desperate banded together with some soldiers and craftsmen and decided to try their luck down below.

Facing numerous hardships, these groups lost many people in the beginning. Eventually only those strong enough or resourceful enough remained, forming a disciplined and cohesive unit. Charismatic individuals with the strength to back up their words, who could bring the group together, reignite the community’s hope, and convince others of their ideas eventually rose to the top as legends.

In some communities it was someone religious, whose convictions drove them to overcome all odds. In others a Wizard or wiseman whose intelligence helped avoid catastrophe. Even a simple musician, whose rousing song kept morale and hope alive when smoke and ash blotted out the skies could become a legend passed down for generations.

These groups have little in common with each other apart from their cohesive unity, and deification some ancestral figure who was the reason for their survival.

Spoiler: The left behind

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While communities that formed down below might occasionally interact with each other and trade or war, those who remained above the old sea level were cut off in isolation.

Not long after the other groups descended or left, dark clouds began forming. The smog eventually thickened until it looked like a new sea to those who had remained. Instead of clear waters and the salty sea breeze, they now had hazy dark clouds and the occasional sulfurous winds.

It seemed as though all who had abandoned them would likely have perished beneath that cursed black smog. Those who remained decided to never attempt the same, with exaggerated horror stories passed down about those who did.

How these isolated communities overcame their lack of water varied from island to island, though it was usually either the one responsible for bringing water or the one who was strongest who eventually took control.

Living isolated for generations, these communities developed in odd ways. Cut off in a way from reality, some formed cults, others becoming more monastic in nature. The occasional violent uprising and society being flipped on its head resulted in some islands even losing all historic documentation of time before the sea abandoned them.

Some of island groups eventually died out, ruins, odd relics and strange texts being the only evidence left of their existence.

Basically:
1) nomadic merchants + land ships
2) disciplined militants + strong culture
3) weird isolationists + ruins and strange tech/magic

[Burley]

I suggest taking a look at real-world deep sea stuff, like brine pools, where the water is so much saltier than the rest of the water, that it forms an undersea lake. For most creatures, it's instant death to swim into, but some can go in for brief periods of time, though it will sent them into toxic shock.

[brian 333]

Sand Traps

Semi-intelligent octopodes saw the water receeding and delved into the sand until they found or created caverns with lakes which are connected to the surface via spiral tunnels. The normally solitary creatures share these pools as communal rest and mating areas, but each has its own tunnel to the surface which it uses to create a food trap.

The octopus uses moistened sand to cover the entrance, then hollows out beneath the crust until only a thin shell remains concealing the conical opening. When something steps on the sand it caves in and the creature falls down the spiral tube to land at the bottom, usually on sharp rocks or with a 20' or farther drop at the end. The octopus may also have a chamber dug to position itself so that it can reach any creature that steps in the trap but manages to avoid sliding into the tunnel. With the yank of a tentacle and a jet of water to lubricate the victim, followed by an octopus dropping down from above to grapple and bite, most victims don't have a chance.

Since most octopodes drag their prey to the edge of the communal pool to dine while they rest, the young spawn which live in the pool may sneak a few bites while the successful trapper rests between meals or gorge on the leftovers.

[sktarq]

Also something you may want to look at is Harry Turtledove's "Down in the Bottomlands" is a novella that may give you ideas

[Bohandas]

Have you established why and how this particular ocean drained? It might be interesting to have the reason be some kind of backward Atlantis story, where a race of sea-dwelling humanoids such as merfolk, sahugin, or sea elves, accidentally drained the ocean through some outrageous act of hubris.

[brian 333]

Have you established why and how this particular ocean drained? It might be interesting to have the reason be some kind of backward Atlantis story, where a race of sea-dwelling humanoids such as merfolk, sahugin, or sea elves, accidentally drained the ocean through some outrageous act of hubris.

In my campaign I actually have a sea which was cut off from the ocean by tectonic uplift and later drained when an overflow channel cut through the new mountains.

Mine has salt pans and brine lakes and ordinary sea creatures adapted to tolerate salt with an assortment of desert creatures. And sand sharks.

[Quizatzhaderac]

I'd invite you to read xkcd's what if: drain the oceans.

So here's how I would describe what happens.

Before adventure
Around the sea, countless small Earthquakes occur, almost regularly, often in places that never knew them. The sea level drops just enough to ruin all the seaside fishing villages. Many once navigable rivers now have rapids in their new (longer) path to the sea.

The seafloor under the straits straights connecting to the oceans rise up and cut the sea off.

The shoreline recedes every day, but slower than a person can walk.

Practical questions abound. How will we replace are trade routes across the sea, with the peoples in the sea? Are we safe from the geological catastrophe, are we safe from those fleeing it?

But above that is just a burring curiosity to understand what is happening to the world and why.

Initial exploration
Old rivers find new paths across a mountainous landscape (avoid saying exactly what altitude changes are involved). Valleys form new lakes which are filled with desperate underwater peoples eager to form new trading partners and build canals and tunnels to connect the lakes.

Harsh torrential rains often hit the region, as if some gods were still undecided if this should be land or water.

The land is unstable: rivers often jump their banks; landslide create dams, a volcano dumps lave, or a magma vent heats a lake to boiling.

One often cannot retrace their steps as there is no permanent path.

At the completion of the draining
Rivers that were mighty in the above combine with each other and the rain and braking damns to form a semi-permanent deluge.

At the final shore there is, not so much a lake, as an extended whirlpool as the water struggles to enter the abyss.

The abyss was once an underwater city, and now is just a whole in the world. Clearly the work of gods, beyond the things that can be changed, but still we mortals must understand and adapt.

Where the water goes is beyond such simple minds as yours. Some way a dessert on another continent has turned green. Some say the abyss will leave the world dry. Some say the other seas are rising.