The Poisoner Base Class

From publisher blurb:

Part herbalist and part assassin, a poisoner is an enigmatic figure who brews noxious poisons for use in their deadly vocation. They have a special talent for remaining out of the way, going unseen, and plying their trade in the shadows. Many favor blow darts or other easily concealable ranged weapons but they’ll settle for anything that can deliver their fatal concoctions.

Some municipalities have sanctioned poisoners or poisoner guilds who both develop poisons for the kingdom and develop counter-agents to them. Snipers and scouts will often go to poisoners to add a particularly deadly sting to their attacks.