Cinnabar Rapier (Patreon)

Weapon (rapier), rare

This magic rapier’s blade is alchemically coated in a thin but toxic layer of cinnabar. The weapon has 10 charges and regains 1d8+2 expended charges each day at dawn. When you hit a creature with this weapon, you can expend 1 or more of its charges. The blade’s poison leeches into the blood of the creature you struck to deal an extra 1d4 poison damage for each charge expended in this way. 

"Cinnabar is used primarily for the arts, but often at the cost of the artists themselves. It can cause convulsions, insanity, and, ultimately, death. So, naturally, I decided that a masterfully crafted blade such as this should share those same effects with everyone else."
-Blaine Grimfire, Dwarven guild artisan