Creating Poisons (Rules and balancing)

[Brymja9711]

Hello everyone.

I am running a homebrew campaign, and one of the characters is a yuan-ti pureblood alchemist artificer. He really enjoys using a poisoner's kit to craft all kinds of poisons. He asked me if he could work with me to come up with new and advanced poisons that are not in the book. Brainstorming session: commence. Thank you in advance for any ideas you guys have (Note: I have come up with a few that are pretty cool, but I need some help in balancing others and coming up with interesting ingredients as well)

[Sparky McDibben]

Hello!

So, the main mechanics for poisons in 5e are inflicting conditions if the target fails a save. So let's see if we can run with that a little bit more:

Will-Sapping Dust (Inhaled). A creature subjected to this poison must make a Constitution saving throw vs DC [crafter's save DC; suggest 8 + prof bonus + Int mod]. On a failed save, the creature suffers the poisoned condition for the next hour. While poisoned in this way, the creature has disadvantage on Wisdom saving throws.
--Modifications: Extend time of poisoned condition to 24 hours if the delivery method is changed to ingested
--Suggested Price: 600 gp

Fangs of Time (Injury). A creature subjected to this poison takes 3d12 poison damage and must make a Constitution saving throw vs DC [crafter's save DC; suggest 8 + prof bonus + Int mod]. On a failed save, the creature suffers the poisoned condition for 1 minute. While poisoned in this way, the creature's speed is halved, and it can either take an action or a bonus action, but not both.
--Modifications: Potentially consider exchanging the "it can take an action or a bonus action, but not both" language with either "the creature's Armor Class is lowered by 2" or "attacks directed at the poisoned creature have advantage"
--Suggested Price: 800 gp

Fool's Root (Inhaled). A creature subjected to this poison must make a Constitution saving throw vs DC [crafter's save DC; suggest 8 + prof bonus + Int mod]. On a failed save, the creature suffers the poisoned condition for 1 hour. While poisoned in this way, the creature automatically fails Investigation checks to discern illusions, and has disadvantage on Wisdom (Perception) and Wisdom (Insight) checks as they hallucinate reactions from the people they speak to that lead them to incorrect conclusions.
--Modifications: Consider changing the poisoned condition result to "disadvantage on all saving throws to resist fear-based effects."
--Suggested Price: 600 gp

Also - have you considered how much work this player will have to do to find recipes and ingredients?

[Brymja9711]

Those are awesome ideas! As far as the ingredients, the player(s) could purchase them if they are common enough (or if they find someone who has rare oddities in their possession) or they may have to search in areas of the world to find them. The more rare components could add some flavor when adventuring on the main course of the story-line, or even go on random side quests. Also, depending on the merchants available in the various areas, the poisons could be purchased by the vial. I also had the idea of creating a magic item that could turn poisons and toxins that are usually in liquid form into a gas, similar to an incense burner.

[Misterwhisper]

The main issue with poison will always be price.

Basic poison is 100g.
That give 1d4 damage once in melee
With a very easy dc to make
On usually critters best save
And does not even apply the poisoned condition.

That is absolute garbage.

To make any poison worth the time to make it, the price would have to be so high that while the effect might be worth it, the price wouldn’t be.

A dose of poison should not cost multiple times more than a magic weapon.

[Sparky McDibben]

The main issue with poison will always be price.

Basic poison is 100g.
That give 1d4 damage once in melee
With a very easy dc to make
On usually critters best save
And does not even apply the poisoned condition.

That is absolute garbage.

To make any poison worth the time to make it, the price would have to be so high that while the effect might be worth it, the price wouldn’t be.

A dose of poison should not cost multiple times more than a magic weapon.

Your analysis is spot on except for two things: The poison can actually deal it out over 3 - 10 rounds (a vial can coat up to three pieces of ammo, or just the weapon), but it takes an action to apply (it's debatable whether Fast Hands affects this). From a gameplay standpoint, requiring a save on every hit with a poisoned weapon also slows the game down. None of these materially affect your conclusion; basic poison is garbage.

However, the joys of homebrew mean that we aren't limited to basic poison. We can also rationalize that basic poison is so costly because it presumably isn't terribly available. No one is selling "Off Your Neighbor Juice" at the local market (unless you have the right contacts!), hence a limited supply, hence a much higher price. Ergo, I would require the player to actually go on adventures to acquire poison recipes and ingredients: "We must find the banded agony viper, known to reside only in the jungles of Defini Telynotafrica!"

Or, alternatively, you could include the recipes as treasure, similar to how you would with a wizard and spell scrolls: "Egads! Devil Tears requires literal tears from an devil? How do you even make a devil cry? But it can create a one-time, miniature sphere of annihilation inside the belly of anyone who ingests it?" [Note: this also means you can introduce enemies that can be killed by certain poisons most effectively, but then require a quest to garner the ingredients].

Finally, not all poisons have to act as negatives; some of them might presage transformations or be tests to be administered or endured: "Zounds! The recipe for Black Lotus Mist, the legendary first step to artificially creating another yuan-ti pureblood!"

[Man_Over_Game]

Try to base the power levels of those poisons around the Battlemaster superiority dice. These add roughly 1d8 to an attack that hits, up to 4 times per Short Rest, and also have the chance of a condition.

You want poisons to be guaranteed to be weaker than that so as to not be overpowered, as the Artificer already has its own subclass (no point in giving him a freebie).

There aren't any hard rules as to how it needs to be, though. You could, for example, have poisons for different categories (Damage, Prone, Poisoned, etc) that he can mix together, Skyrim-style.

For example, he has x1 Damage materials, x2 Prone materials, x1 Exhaustion Materials. He can combine a number equal to his proficiency into that many dosages, causing him to roll for each (adding +5 for any duplicates), with the base DC being 1/2 of his skill roll. So if he wanted to mix a potion with 3 ingredients, with x1 Damage and x2 Prone, it'd deal 1d6 poison damage on a hit and then he'd have to roll a Save that has a DC equal to half of his Poisoner's Kit Check + 5.

To control the power level of certain conditions, you just throttle how much of that material they're able to find. So if they are trying to find a poison that paralyzes you for 30 seconds, that's gonna be a lot rarer than something that simply knocks you Prone or makes you Exhausted.

Add an expiration date to materials gathered, poisons made, and poisons applied to avoid scenarios where he spends all day gathering herbs as a money-making or powergaming strategy, simply increasing the quantity of gathered herbs to compensate (so he might get a bunch of good herbs, but an unrealistic window available to use them all).

[Ninja_Prawn]

My time to shine! I published a bunch of poisons on my blog last week (https://mfov.magehandpress.com/2020/06/poisons-into-wilds.html), which I will copy here - along with some older ones - for ease of reading. There's a bit of a Feywild theme going on, so they might need refluffing for general use.



Name
Type
Price per Dose


Black Scourge
Contact
500gp


Boggart's Mischief
Inhalation
99gp


Caustic Fog
Contact
50gp


Concentrated Euphoria Gas
Inhalation
150gp


Fairy Sugar
Ingested
200gp


Fog of Mirages
Inhalation
750gp


Heartfreeze
Ingested
2,500gp


Lies Serum
Ingested
100gp


Mindwhisper
Inhalation
250gp


Night Terror
Injury
500gp


Queen's Poison
Contact
5,000gp


Quintessence
Injury
250gp


Sleeping Poison
Injury
25gp


Vision Cap
Ingested
600gp


Water of Darkness
Contact
800gp



Black Scourge (Contact). This slimy toxin kills any nonmagical plant it comes into contact with; one vial contains enough to cover all plants in a 10-foot cube. Any plant creature that touches this poison must make a DC 17 Constitution saving throw, taking 36 (8d8) poison damage on a failed save, or half as much on a success. This poison treats plant creatures that are immune to poison damage as if they only had resistance.

Boggart’s Mischief (Inhalation). A creature that breathes in this poison must make a DC 13 Intelligence saving throw or be poisoned for 1 minute. While poisoned, the target suffers an additional effect, determined by rolling 1d6 on the following table:




Roll
Effect


1
The target is muted (see below)


2
The target is deafened


3
The target’s base speed is reduced by 10 feet


4
The target is charmed by the first creature it sees


5
The target takes 2 (1d4) poison damage at the start of each of their turns


6
Roll twice and apply both effects (ignore further sixes)


Caustic Fog (Contact). This poison must be delivered into an enclosed space via a misting device. One dose can fill a volume up to 5,000 cubic feet. When deployed, it takes 10 minutes for the fog to reach effective concentrations, and then persists for up to 1 hour if not displaced by fresh air. A creature exposed to this gas must make a DC 15 Constitution saving throw or lose the benefit of any natural armor they may have for as long as they remain in the fog -- creatures without natural armor are not affected by this poison.

Concentrated Euphoria Gas (Inhaled). This smoky gas, exhaled by faerie dragons, shifts color constantly, casting a prismatic glow on everything around it. Each creature that inhales it must make a DC 16 Constitution saving throw or be poisoned for 1 minute. The creature can’t take actions, bonus actions, or reactions and must roll a d4 on the table below to determine their behavior. The poisoned creature can reattempt the saving throw again at the end of each of their turns, ending the effect on a successful save.




Roll
Effect


1
The poisoned character moves as fast as it can in a random direction, with a new direction chosen every turn. It believes it is fleeing from a swarm of wasps.


2
The poisoned character stands on the spot, laughing uncontrollably. It is completely unable to explain what it finds so funny.


3
The poisoned character can see 60 feet into the Ethereal Plane, but is blind to their true surroundings, including creatures. They are totally awestruck and cannot communicate in any way.


4
The poisoned character gains the Sunlight Sensitivity trait for the next hour. This effect can only be removed by magic such as lesser restoration (the saving throw does not end it).


Fairy Sugar (Ingested). This bittersweet powder, made from dried mushrooms, causes painful stomach cramps in its victims. A humanoid subjected to this poison must succeed on a DC 13 Constitution saving throw or be poisoned for 1 hour (creatures other than humanoids suffer no ill effect). While poisoned, the target’s base movement speed is halved. The target can repeat the saving throw at the end of each of its turns, ending the effect on a success.

Fog of Mirages (Inhaled). A creature subjected to this poison must succeed on a DC 15 Intelligence saving throw or be poisoned for 10 minutes. The poisoned creature perceives a false image of their immediate surroundings, as if a hallucinatory terrain spell had been cast, centered on the creature. The creature that made the poison can set general tones and themes for what the false images will contain, but the bulk of what a victim sees is drawn from their own subconscious. The GM determines exactly what images appear. The creature can repeat the saving throw once per minute, ending the effect on a success.

Heartfreeze (Ingested). A creature subjected to this poison must succeed on a DC 15 Constitution saving throw or be poisoned for 10 minutes. The poisoned creature is paralyzed. The creature can repeat the saving throw once each minute, ending the effect on a success. If the creature is paralyzed by this poison for the full 10 minutes, it suffers a heart attack and drops to 0 hit points.

Lies Serum (Ingested). A creature subjected to this poison must succeed on a DC 11 Constitution saving throw or become poisoned for 1 hour. The poisoned creature can’t knowingly tell the truth, even if another spell or effect would force them to.

Mindwhisper (Inhalation). This fine powder stings slightly when inhaled. A creature exposed to it must succeed on a DC 15 Constitution saving throw or be poisoned for 1 minute. While poisoned, the victim has disadvantage on Wisdom saving throws against spells or effects that would force them to take a specific course of action.

Night Terror (Injury). This poison, derived from the venom of the rainbow rabbit, reveals its true nature when night falls. A creature exposed to it must succeed on a DC 12 Constitution saving throw or be poisoned for 24 hours. While poisoned, the creature cannot benefit from taking a long rest. However, all of the effects of this poison are suppressed if the victim is in direct sunlight.

Queen’s Poison (Contact). A creature subjected to this poison must succeed on a DC 19 Constitution saving throw, taking 65 (10d12) poison damage on a failed save, or half as much on a successful one.

Quintessence (Injury). This ineffable extract fizzes and sparkles with otherworldly power. A creature subjected to it must succeed on a DC 15 Charisma saving throw or be poisoned for 1 minute. At the start of each of its turns, the poisoned creature is teleported to a random unoccupied space within 30 feet of it. The creature can repeat the saving throw at the end of each of its turns, ending the effect on a success.

Sleeping Poison (Injury). This poison, brewed mainly by sprites, induces a brief, pleasant sleep. Fey creatures often use it to incapacitate big folk who trespass in their realms. A creature subjected to this poison must succeed on a DC 10 Constitution saving throw or be poisoned for 1 minute. If the result of the saving throw is 5 or lower, the creature also falls unconscious for the same duration.

Vision Cap (Ingested). This visually unremarkable fungus makes it difficult to tell illusion from reality. A creature that consumes this poison must succeed on a DC 13 Constitution saving throw or suffer the hallucinating condition (see below) for 1 hour.

Water of Darkness (Contact). This jet black liquid smells horrendous and contains enough evil to make nearby paladins feel faint. When a creature is subjected to this poison, it must make a DC 17 Constitution saving throw or be poisoned for 1 minute. While poisoned, the target’s hit point maximum is reduced by 14 (4d6) and if it has the Regeneration trait, that ability does not function. The target can repeat the saving throw at the end of each of its turns, ending the effect on a success.

Hallucinating. A hallucinating creature gains the Sunlight Sensitivity trait, treats all ground as difficult terrain, and can never succeed on an ability check or saving throw against an illusion.

Muted. A muted creature cannot speak or perform the verbal components of spells.
Edit: I just read Sparky McDibben's post above, and realised how similar Mindwhisper is to their Will-Sapping Dust. Great minds think alike, I guess. Or we're both making references to the same thing... (in my case, Noranti from Farscape)