In relation to This Question, I want to continue on the poison train of thought.
Many D&D games have absolutely horrible poisons and rules to the effect that around level 11 poisoning is almost never going to be effective and especially not cost effective. Based on the answer to the last question, I feel more confident that you can make poisons be a little more effective for a ridiculous cost. Now, let's try and see if we can properly optimize them.
The requirements for optimization:
- Poison should work at least 50% of the time against an average CR13 monster (assume base save between 13-16).
- Little chance of accidentally poisoning yourself at any point in the preparation or use. (It's obvious, but worth mentioning).
- You can safely ignore poison immunity because there is nothing we can do about that existing.
- Poison preparation should take the least amount of time possible <1hr is preferred.
- Poisons should be deadly (=>40% chance of either killing or long term incapacitate)
- [optional] Poisons should be reusable (the more effects you can get out of a single dose the better).
- In the event multiple paths fulfill all the requirements, the one with the lowest cost per effect will be the accepted answer (crafting/buying cost of a dose/number of uses per dose)
- You only have to pick one poison with your build and show it meets the criteria, it needn't be done with all poisons.
You have up to a level 13 character to work with (mostly because I don't think you can continue to optimize for encounters above this). Any material is allowed. For obvious reasons Alchemist is preferred, but use whatever you have.
The ultimate goal here is to see if you can honestly create a character who can effectively use poisons without feeling like you just wasted feats and such later on. To that extent, it's also blatantly obvious that you don't want the character having to spend all their wealth just buying poisons without being able to also deal with gear.
Best Answer
The Eldritch Poisoner
The Eldritch Poisoner archetype (from Black Markets) replaces the Alchemist's bomb ability with the ability to create a unique poison, arcanotoxin. This toxin can be created as a standard action and applied to a weapon as a move action (at level 1). It's also free.
At every even-numbered level, you can upgrade your arcanotoxin. Here's an example for a level 13 - Eldritch Poisoner:
Discoveries
Normal alchemist discoveries don't alter arcanotoxin. Thankfully, the archetype has some other discoveries you might be interested in:
Other Stuff
Finished Result
After taking these into account, a level 13 Eldritch Poisoner with 20 Intelligence can create an arcanotoxin like this:
Results
With saves between 13-16, a creature would succumb to arcanotoxin 40%-55% of the time. This barely squeaks by your conditions.
This build is immune to poison, from the level 10 alchemist poison immunity ability.
Arcanotoxin can be created and applied to a weapon as a single move action (thanks to the Envenom discovery available to this archetype). Additional mundane poisons can be created using half of the normal time (from the Toxicologist archetype feature).
If the creature's save is 13, on average it will be poisoned for 3 rounds. During this time the poison can deal 3 - 18 Constitution damage. This may not be lethal, but it will do considerable harm. Nausea will prevent the creature from doing much besides moving.
A single usage of arcanotoxin is only a single dose, but you can prepare additional doses as a move action. At level 13, you could do this 18 times per day.
And the best part - arcanotoxin is free! Monetarily anyway.