I am DMing a homebrew campaign and I created an exotic island ruled by Yuan-ti. I read the Serpent Kingdoms 3rd edition manual and I tried to adapt the osssra table (page 150).
In 5th edition the condition Poisoned tries to simplify the effects of poisons, even if in DMG (pages 257-258) some different poisons and their effects are described. I was actually fascinated by the different osssras' effect on both Yuan-ti and scaleless ones (i.e. non Yuan-ti creatures): collapsing every dangerous effect in the Poisoned condition seemed to me quite inadequate. I thus wrote the following rules.
Osssra Oils
From Serpent Kingdoms:
The creations of yuan-ti spellcasters, osssra oils are mixtures of
substances that produce pungent, colorful smoke when burned. Osssra
smoke confers benefits on all Scaled Ones but functions as an inhaled
poison for all other creatures.
and
The secrets of making osssra oils are guarded by yuan-ti tribal elders, and most humans know too little about them to distinguish one from another.
A Yuan-ti spellcaster/alchemist prepare the osssra oil, then let soak some pieces of wood in the oil for at least 3 days. After this amount of time, the wood is ignited (in a brazier, for example) and the smoke starts to spread, at the speed of 1 foot/round, until the full area of effect is reached (a sphere of 20 ft. radius).
The osssra’s smoke are used in religious rituals, where priests ask for gods’ favour in battle or try to communicate with superior entities (see Duthlah’hass). The ceremony duration depends on the priest, but in order to gain the benefit provided by an osssra smoke a Yuan–ti must stand still in the smoke cloud and inhale it for at least 10 rounds, except for Hooloond.
$$
\begin{array}{|l|l|l|l|}\hline
\textbf{Osssra} & \textbf{Ingredients} & \textbf{Smell and aspect}& \textbf{Price (gp)}\\\hline
\text{Amasstarte smoke} & \text{Sap from silverthorn weed,}& \text{Green, with silvery} &500\\
& \text{boiled scales from } & \text{metallic flecks; spicy.}\\
& \text{any salt-water fish.}\\\hline
\text{Battasss smoke} & \text{Palm oil, petals of the } & \text{Ruby-red, with darker}& 800\\
& \text{fallen snow flower.} & \text{"threads";scorcing milk}\\\hline
\text{Duthlah’hass smoke} & \text{Mint, bark of palm }& \text{Bright amber;}& 1200\\
& \text{and sap of jungle clingvine} & \text{burnt moss.}\\\hline
\text{Ektharisss smoke}& \text{Purple leaves of the} & \text{Dark purple, with puffs of} &800\\
& \text{nightshadow jungle plant.} & \text{lighter blue color; lemon.}\\\hline
\text{Faele smoke}& \text{Boiled boar brain} & \text{Deep blue, with emerald} & 1800\\
&\text{and human blood.} & \text{streams; rotting flesh.}\\\hline
\text{Hooloond smoke}& \text{Blood of a constrictor snake} & \text{Yellow-green, with red} &1400\\
&\text{and the venom of a viper.} & \text{jets similar to flames; melon}\\\hline
\text{Jalasss smoke} & \text{Crushed snails and} & \text{White; burning paint.} & 800\\
& \text{sap of launteene.} \\\hline
\text{Laerisss smoke} & \text{Crushed centipedes } & \text{Brown; burning} &300\\
&\text{and palm oil.} & \text{olives}\\\hline
\text{Ruusstantar smoke}& \text{Snakeskin and} & \text{Green, with ribbons of} & 500\\
&\text{crushed boar bones.} & \text{purple vapour; freshly }\\
& &\text{crushed grapes.}\\ \hline
\text{Ulathlasss smoke}& \text{Internal juices of both} & \text{Dark green;} &1500\\
& \text{carrion crawlers } & \text{roasting boar}\\
& \text{and centipedes.}\\\hline
\end{array}
$$
Yuan-ti avoid combining different kinds of osssra smoke, because their effects interact negatevely and/or negate themselves. Moreover, if pieces of wood are soaked in a mixture of different osssra oils and then burned, the result is a smoke that harms each creature in the area of effect (see the table).
If a creature tries to dismiss the smoke produced by burning wood, e.g. using the gust of wind spell, then the area is immediately cleared, but the vapour keep on spreading at the speed of 1 foot/round from the burning source. If a creature manage to light off the source, then the smoke dissipates after 6 rounds (or depending on the room, presence of windows, et cetera).
Effect of Ossra on Yuan-ti
In order to gain the advantages given by an osssra, a Yuan–ti must inhale osssra’s smoke for at least 10 rounds, except for Hooloond. A brazier spreading osssra’s smoke covers a circular area of 20 ft. radius (as the fog cloud spell) except for Ulathlasss which covers an area of 15 ft. radius (due to its particular "heaviness").
Legend:
- Adv. -> Advantage
- Disadv. -> Disadvantage
- rds -> rounds
$$
\begin{array}{|l|l|l|}\hline
\textbf{Osssra} & \textbf{Effect} & \textbf{Duration}\\
\hline\hline
\text{Mixed flaming } & \text{Disadv on DEX checks and Ranged attacks } & \text{2d6+2 rds}\\
\text{osssra oils}& \text{(20 CON save, no effect on success)} &\\\hline
\text{Amasstarte smoke} & \text{Cure Wounds 4d8+8} & /\\\hline
\text{Battasss smoke} & \text{Adv on WIS checks, automatic success} & \text{10 minutes}\\
& \text{for Concentration spell checks after taking damage}&\\\hline
\text{Duthlah’hass smoke} & \text{The yuan–ti enters in a dreamsleep state (such as} & \text{4 Hours.}\\
& \text{under the Dream spell), in which he can retrieve} & \text{Ends on }\\
&\text{memories (such as where or how they hid something} & \text{damage taken.}\\
& \text{long ago, or snatches of overheard conversation)} \\
& \text{and/or receive messages from their deities.} & \\\hline
\text{Ektharisss smoke} & \text{Levitate} & \text{10 Minutes}\\\hline
\text{Faele smoke} & \text{Adv on CON saving throws, resistance } & \text{4 Hours}\\
& \text{on piercing, bludgeoning and slashing damage}\\\hline
\text{Hooloond smoke} & \text{Cure Wounds 1d6+1/round while }& \text{Instantaneous,}\\
& \text{in contact with the Hooloond smoke} & \text{max 10 rds}\\\hline
\text{Jalasss smoke} & \text{Immune to Enchantment spells} & \text{4 Hours}\\\hline
\text{Laerisss smoke} & \text{Adv on DEX checks and ranged attacks} & \text{4 Hours}\\\hline
\text{Ruusstantar smoke} & \text{1d12 (inhaled smoke) or 2d12 (contact } & \text{4 Hours}\\
& \text{with osssra) Temporary HP} \\\hline
\text{Ulathlasss smoke} & \text{Resistance to Fire and Cold damage} & \text{4 Hours}\\\hline\hline
\end{array}
$$
Effect of Ossra on Scaleless Ones
As soon as a scaleless one enters in an area where an osssra smoke is present, the creature has to make Constitution saving throw (DC set by the type of osssra in the table below). Even in case of success the osssra’s smoke induces damages and/or disadvantages. The effects are active as long as the creature stands in the area covered by the smoke (see previous section for the dimension). If the creature exits the area, it make a Constitution saving throw or suffer from the secondary effect for 1d4-1 (min. 1) more rounds.
$$
\begin{array}{|l|l|l|l|}
\hline
\textbf{Osssra} & \textbf{DC} & \textbf{Effect on failed save} & \textbf{Effect on succeeded save} \\\hline
\text{Mixed flaming osssra oils} & 20 & \text{4d4+4 Poison, Poisoned} & \text{Poisoned} \\\hline
\text{Amasstarte smoke} & 13 & \text{Paralized, 1d4+1 rds} & \text{Slow, 1d4+1 rds} \\\hline
\text{Battasss smoke}& 13 & \text{Poisoned} & \text{Disadv on WIS Checks} \\\hline
\text{Duthlah’hass smoke} & 14 & \text{Unconscious, 1d4+1 rds} & \text{Prone (for retching).} \\\hline
\text{Ektharisss smoke} & 14 & \text{2 exhaustion levels} & \text{Speed halved} \\\hline
\text{Faele smoke} & 14 & \text{Stunned}& \text{Disadv on CON checks} \\\hline
\text{Hooloond smoke} & 16 & \text{4d6 Poison} & \text{Half damage} \\\hline
\text{Jalasss smoke} & 13 & \text{3d6+3 Poison, Disadv on INT } & \text{3d6+3 Poison}\\
&&\text{and WIS checks}\\\hline
\text{Laerisss smoke} & 14 & \text{2d4 Acid damage,} & \text{2d4 Acid Damage}\\
&& \text{Disadv on DEX checks}\\\hline
\text{Ruusstantar smoke} & 14 & \text{4d4+4 Poison} & \text{Half damage}\\\hline
\text{Ulathlasss smoke} & 15 & \text{1d6+1 Poison,} & \text{1d6+1 Poison} \\
& & \text{Incapacitated, 1d4+1 rds}\\\hline
\end{array}
$$
Discussion
I have the following thoughts about what I wrote.
- I tried to follow some logical connections between the effects on Yuan-ti and on scaleless one.
- Are the DCs balanced? Maybe they are quite low, but even in case of a successful saving throw a creature has some disadvantages, hence I thought it was a good way to create a sort of equilibrium.
- I decided to put effects on successful saving throws because I think that these osssras are very powerful.
- Is it ok to make the effect lasting after a creature exits the smoke cloud?
- The cost (in gp) is very similar to the table of the 3rd edition, but I did not pay too much attention to it. It is up to the DM allowing players to find ingredients and knowledge about preparing osssras,
Best Answer
In this case, you're probably asking the wrong question.
The thing you're discussing here is a tool for the DM, designed to benefit NPCs. Its primary effect is going to be in adding PC-hostile terrain effects to encounters, probably mostly combat encounters. That means that "balanced" isn't a particularly meaningful question to ask. Instead, it's going to be a matter of adjusting encounter difficulty. You're listing prices, but the prices aren't really important unless the PCs manage to seize some and find a merchant willing to buy the stuff. After all, the smoke spreads from lit braziers. How often are the PCs going to be in an encounter where they have the time to set up a brazier and light it?
Instead, the question that you should mostly be asking is with respect to individual encounters, on whether the difficulty is in line with how hard you want the encounter to be, once the smoke clouds are taken into consideration. Even on the off chance that the party manages to briefly acquire the assistance of some Yuan-Ti and have an encounter where deploying this stuff would make sense, it's still a matter of balance for that specific encounter.
If you do intend this to be something that the party is buying and using, you have other issues.
First, you're talking about single-use alchemical items, some of which have price tags in excess of plate mail. 5e isn't designed for stuff like that. By the time you get enough money that buying some of this stuff would make sense for general use, you should already be on the magic item economy for your gear-based boosts.
Second, there's the fact that this is uniquely beneficial to Yuan-Ti. That makes the first issue much worse. If you have any yuan-ti in the party, then once the party becomes appropriately wealthy, they get significant benefits from being able to lay out raw cash, at a level when "lay out raw cash" isn't supposed to get you much of anything. Basically, this becomes a backdoor buff of the Yuan-Ti race, and the Yuan-Ti race is already one of the strongest PC races in the game.
Third, you need more info. Most of the time, the party gets into fights without warning. Sometimes they have time to prepare. For the first case, you need to know how hard it is to prep a brazier with one of these things, how fast it spreads once you have, how hard it is to disrupt once it's burning, and what happens if you just light the thing and chuck it on the ground. For the second case, you also need to know how long the smoke lasts once it's been produced.
In general, then, introducing this stuff as something that the party is expected to acquire and use in general is probably a mistake. Introducing it as a terrain feature to make certain fights more interesting is great. If you're doing the latter rather than the former, then "balance" is not the way to be thinking about it.
For your own usage, you might be well-advised to start small and work up with this stuff. Start by giving the party an encounter that should be a cakewalk, plus one cloud of ossra positioned such that it will be a meaningful benefit to the enemies. That will give the party a chance to encounter it (and realize what they're dealing with) and you a better idea of how much difficulty it's worth. Then work your way up the chain, both in using ossra and overall difficulty. That way, once you get to your particularly challenging climactic ossra-based encounter or encounters, you'll have a much better idea of how much difficulty they're actually worth (and your players will have a better idea of how to handle them).