So, recently read randomly through the Witcher-wiki (the games by CD Projekt), and found out in the first game, there's a potion giving the character poisonous blood.
Figured that'd be an actually really awesome feat to be unlocked by some quest line, or maybe a recipe of the same origin, to kill those annoying bloodsuckers and damage anything attacking without weapons.
Now don't tell it it doesn't make sense, spiked armor enhancing electric sledgehammers didn't make sense, either!