Source of a poisonous atmosphere harmful to intelligent races, but not wildlife

Question

I am running a D&D 5e campaign and planning out the next arc. I want to do a Final Fantasy crystal chronicle-type world, where there is a miasma present throughout the world and major cities and normal adventurers need crystals to keep it away from them, creating a bubble that they need to stay in to breathe normally.

I'm having troubling justifying the miasma hurting player characters and normal villagers in towns, but still having the rest of the world feel unaffected. I want the miasma to have appeared in this world a few hundred years ago, so evolution wouldn't make sense.

Why would it not hurt goblins or orcs or ogres or owl bears, foxes and other wildlife?

Answer 1

There are many poisons that only affect a small group of animals.

There is a spider in Australia that is deadly to humans but does not affect dogs. I will look for a reference.

So this miasma could be semi-magic and target humans or only affect a subgroup of animals and that is why this area has the ecosystem it has.

from https://australianmuseum.net.au/spider-facts heading "What is the world's most dangerous spider?"

The Australian funnel-web spiders are among the deadliest spiders in the world in the effect their bites have on humans and our primate relations (although the bite has little effect on dogs and cats).

If you need that poison to affect all player races it might help if it were a group of different toxins that was designed that way by some force.

Answer 2

I would suggest making the miasma a cloud which provides ideal breeding conditions for an airborne disease. This disease (like many others) only affects humans and certain other very similar species (which mostly happen to be the intelligent species).

I have fewer answers for the crystals, but I'd suggest that they emit a certain kind of magic that kills the disease within a certain radius - think a magical equivalent of UV radiation.

Answer 3

The miasma doesn't harm animals because the miasma only affects intelligent races.

The reason orcs and ogres aren't affected is because they are already tainted by the miasma. Given enough time all intelligent life would turn monstrous if exposed to the miasma.

The source for the miasma is obviously magical. Some big spell cast either deliberately or having gone awry.

Answer 4

It drains your mana

Wildlife does not rely on mana to survive. Orc, ogre and troll rely on brute strength (although I believe they are intelligent, to some extent).

The only race that is bothered by this kind of miasma is human. And elf. Even non magic-user and commoner will feel the side-effect, such as headache, dizziness, and cold symptoms because they inherently have magic. Orc, ogre, and troll can ignore the symptoms because they naturally have high vitality.

Note: I'm aware that DnD does not use mana to cast spell, so you can just change this to "drain magic power".

Answer 5

TLDR: Intelligent races share a physiological feature that other animals do not.

My answer is inspired by the failure of model organisms from drug trials.

Animals are often used for drug studies, but the differences in animal and human physiology can make bad models for some human drug reactions. After all, you don't find catnip intoxicating the way Fluffy does.

In some extreme cases, drugs show no side effects in one animal model, and are deadly in humans.

The arthritis drug Vioxx appeared to be safe in animal studies, but was withdrawn from the market in 2004 after causing over 60,000 deaths in the U.S. alone. (Source: http://www.neavs.org/research/limitations)

Your characters share some physiological trait that is not shared by goblins or orcs or ogres or owl bears, foxes and other wildlife.

I'm not a biologist or neuroscientist, so I'm a bit iffy on what a good target physiological trait would be. A quick search for "human animal brain difference" suggests a large prefrontal cortex and high connectivity of the brain. Maybe your miasma is a neuro-inhibitor that targets prefrontal cortex connections.

On the other hand, the difference doesn't have to be in the brain. The mechanism for catnip intoxication in cats seems to mostly be about smell reception (they stop responding because they suffer from olfactory fatigue). It's the difference in our nose, not our brain, that makes us less susceptible.

You could take almost any physiological feature, unique to your characters, and blame it for miasma susceptibility.

Answer 6

Okay this is slightly left field but the other way to go at this is to have the "miasma" be the native atmosphere of the races that aren't playable. If the playable, intelligent, races are all from a particular ecology (the world of the campaign) and the NPC races are actually alien to their world, then it makes sense that they can't easily breath the air that the native lifeforms take for granted but produce, and live in, something the home team find poisonous. As for the other "lower" parts of the local ecology, the flora and fauna; plants are easy, they have completely different needs in an atmosphere than fauna, the fauna may be effected but it's either not obvious because the aliens have equivalent species that are taking over anyway or the toxins are reasonable species specific and don't effect most of the fauna species.

In story terms you get something like "the appearance of the "green skins" several centuries ago was strangely coincident with the start of the miasmic storms, waves of poisoned air pouring out of the north where the armies of the goblins lair up during the day."

Answer 7

Coccidioidomycosis is better known as Valley Fever. It's a fungus that only affects mammals. Valley fever is not contagious, so it cannot be spread from human to human. In the real world, only about half those who inhale the fungus will even get sick. Sickness can range from flu-like symptoms, to severe pneumonia, to death. This fungal infection does not seem to affect children. It is more prevalent in older people and people with compromised immune systems.

Notable coccidioidomycosis signs and symptoms include a profound feeling of tiredness, fever, cough, headaches, rash, muscle pain, and joint pain. Fatigue can persist for many months after initial infection. The classic triad of coccidioidomycosis known as "desert rheumatism" includes the combination of fever, joint pains, and erythema nodosum -- painful bumps under the skin.

This is an example of a disease that exists in the default world that could thrive in your world. Maybe the disease effects people in cities as well, but due to efforts by cityfolk, the disease happens less in cities because they avoid growing conditions where Coccidioides fungus would thrive.

Maybe Orcs, foxes and bears are immune due to differences in biology, but it causes a certain death in humans.

Stay immune and good luck.

https://en.wikipedia.org/wiki/Coccidioidomycosis

Answer 8

The miasma could have high concentrations of mercury or other heavy metals. These are harmful to intelligent races because they make them less intelligent, but are less harmful to unintelligent races because they don't have as much intelligence to loose. Short term exposure wouldn't be too dangerous, but you wouldn't want to live in the miasma because the metals would build up and damage your intelligence.

Answer 9

Polution

Make the miasma being produce for humans presence only, the more concetrated an area is with people it becomes more ticker and poisonus. Making carrying crystals an obligatory item if you are heading inside a city or town.

A lone group of adventurers trecking in the forest would leave the presence of this miasma wandering for a few hours, but not enough to cause harm to any of the things around them.

Answer 10

It would be very cutting edge if you introduce something related to CRISPR. We are able to edit genomes now with this method, and scientists are playing around with it in a bunch of model systems. The obvious application is to improved human health.

I'd be tempted to write into the dungeon that gene editing on (whatever peoples you want) has had the unexpected side effect that they are now susceptible to your miasma.

Answer 11

Chemistry. Proteins and amino acids. In human body, as far as I know, all the proteins we use are made outta L-amino acids, meanwhile there are also D-amino acids and those last mentioned are mainly toxic for us.

When I was reading P Chapman's answer, it reminded me about a case with one frog/toad that has poison on her skin all over the body. I don't remember the species name of it but that's not the thing. When this frog was discovered scientists tried to make a lab sample of its poison. The poison was in fact a protein, so they've made a sample using necessary for this protein amino acids, but when it came to testing... It was harmless.

Several years later, it was discovered that the reason for this was in two amino acids that were of D-type, meanwhile scientists were working with L-types. So, as soon as they've changed the L-types to D-amino acids, poison started working as it was supposed to.

The main point of mentioning proteins and amino acids is to show how the structure of something's chemical formula might affect its characteristics. Now for the answers:

1) Where is this "miasma" coming from: let's suggest that plants or some minerals (or a combo) do produce some sort of gas (further NPG – nature produced gas), which is spreading pretty fast and that they produce it in large amounts due to the current atmosphere balance of elements and gases.

2) Why there was no “miasma” before: it was but in a much lower amount. When humans and others arrived their activities have changed the balance of elements and agents in the atmosphere as well as other factors like temperature and more or less – climate. This ended up in plants/minerals/combo being able to produce ways more NPG and allowed NPG to stay longer in the atmosphere without wearing off as it used to be before. Also check № 4).

3) Why not all the living things are affected: for wildlife forms (birds, animals, insects and apparently orcs and others too) - they do either eat the plants, or the fruits of those plants, or do lick/add to the food while cooking the minerals (like some wild pigs to get salt and some other minerals) which makes them Immune due to feeding chains. Alternatively, they eat/harm themselves with the crystals to store them/their parts in the blood/bodies, which provides constant resistance while the crystals are in.

4) How do crystals work: Those crystals are natural antidotes, due to producing agents/substances (further CPS - crystal produced substance) that are binding the NPG particles. The short-area effect is due to that CPS is wearing off in a changed atmosphere/climate unlike NPG, which is now able to be more stable. Also that is onother reason why there was no “miasma” before – original atmosphere’s balance of gases and temperature allowed CPS bind with all the NPG produced, but now crystals produce less CPS and it is not so stable.

5) Alternatively, in case the wildlife/orcs & Co do not eat/harm themselves with crystals, but do add NPG-producers to their meals – crystals might be affecting them negatively (same way as “miasma” affects humans & Co) but only when crystals are close enough. This might also be a reason for faction conflict.

P.S.: I have only a slight knowledge of biochemistry (attended couple of lectures and seminars). Also some (or many) grammar/spelling mistakes might acquire. I’m really sorry for this, I was using MS Word to check it. Feel free to correct me where I was wrong. Thank You.

Answer 12

Radiation. Look at the contaminated zone around the remains of the Chernobyl power station. It's teaming with wildlife which appears largely unaffected, but humans either don't live there or must be very careful where they go and how long they spend in contaminated areas.

So why is this? Are the animals immune to radiation? No, not particularly, although natural selection will push them towards higher radiation tolerance, not enough time has passed yet for an effect to be apparent. The animals die of cancer and radiation sickness just as much as humans would, the difference is that the health of an individual animal isn't so important as long as the breeding population survives.

The cause doesn't have to be radiation, anything which increases the chances of an early death but doesn't generally kill you outright will keep intelligent species away without making much difference to animals.

Answer 13

If i'm not mistaken, our intelligence comes from our prefrontal cortex. If this "cloud" affect this part of the brain, it could explain why it affect intelligent being. It could reduce them to animal like behavior (or kill them).

Answer 14

there is a miasma present throughout the world and major cities and normal adventurers need crystals to keep it away from them, creating a bubble that they need to stay in to breathe normally.

A very similar plot device is present in Tom Kratman's Carrera's Legions. On the planet Terra Nova, almost all flora is laced with a toxic neurochemical designed to interfere with the higher brain functions. Animals are immune, children that survive will grow up brain-damaged, and adults are killed outright.

You could have the flora produce such a chemical as pollen.

Radiation from the crystals, while innocuous to humans, would disrupt the molecular structure of the neural poison until it is harmless when inhaled.

Of course, this means that an airtight shelter needs only have crystals by the airlocks (but this probably would apply also to most kind of non-handwavium miasmas).

Alternately, the same effect can be obtained with electromagnetic noise from piezoelectric structures deep underground (this was a possibility first contemplated by Persinger et al.). In this case the crystals would interfere with the harmful emissions, generating a "bubble" of safety. Damage to the brain would be proportional to the time spent in the open, reversible in the beginning, and becoming irreversible after a long enough exposure. Again this could only affect complex enough brain functions in mammals.