It takes an intensely disliked person to have been poisoned enough to have built up a resistance, but this is where you find yourself. Your liver and kidneys are so good at filtering poisons and toxins that you can't finish your ale without a chaser of Wyvern venom. You gain the following effects:
You gain +1 Con to a maximum of 20.
You gain resistance to poison damage.
You have advantage on saving throws VS poisons.
If you pass a saving throw VS a poison effect, you can slow your heart rate to postpone the effects of the poison. Roll a D6. You may survive that many turns before needing to take another saving throw for that poison, or D6 minutes if you are out of combat.
If you have been affected by a particular poison before, you can forever identify it instantly if you are affected by it again.