D&D 5E PCs using poison

[aco175]

Add monsters that have poison that can be harvested. The PC can now be rewarded like a scroll. Maybe have a DEX check (sleight of hands) to harvest 1d4 uses. Have the player come up with some ideas on how the poison works based on what monster poison. Some just do damage which might have to be added to rare ingredients to make the benefit equal to cost.

 

[aco175]

Another idea is to have the player come up with items to hide the poison in like rings and arrow tips. Maybe a secret smith can make some of these for the right price, of course after the PC save him or finish a quest or both.

Another thing to think about is using poisons in cities and towns and how the law looks at it. You do not want to punish the player for what he is playing, but the bonus damage needs to balance with a cost and this could be one of them if the law looks down on poison.

 

[jgsugden]

In terms of what poisons can do, I'd look to the real world for inspiration:

• Paralytics could give disadvantage or paralysis depending upon strength.
• Poison damage is an obvious option.
• Levels of exhaustion work. So would reduced speed.
• Putting you to sleep.
• Drug-like effects: Crown of Madness, Dissonant Whispers, Phantasmal Force
• Disease.

... then I'd look to fantasy ideas.

• Burning blood - literally causing spontaneous combustion.
• Turning to stone.
• Corruption that steals the soul (removes max hit points)
• Inflict a ghost upon the target.

These can be big gains in power. As such, there needs to be a cost - like taking levels in a class. You could either make it a subclass, or make a poisoner class that is only a few levels long. You could also just give it a gp cost - like buying a potion is just a gp cost and is available in many games. If you go the gp route, the cost needs to be significant.

 

[Stormonu]

Potion and Poison are only a couple letters off from each other, and there is always a potion of poison anyway. Poison does have the advantage it can be administered in different methods beyond being drunk - contact*, injection, inhalation.

My point being, using potion costs, effects and methods of creation for poison is a good way to go as poisons tend to essentially be potions with negative instead of beneficial effects.

* magical salves or ointments would similar in this case, such as Keoghtom's Ointment