The blackboard of the middle ages
A brightly colored ink that hardens the skin.
A small, ordinary looking red pouch that deters all but the most skilled thieves.
This thick sauce, usually a condiment on the platters of the rich, has found a niche in the equipment of thieves.
Want to avoid fighter types focusing on swords? Make Longswords and Bastardswords the weapon of the Noble class, with a death penalty for other to carry. These weapons will be ornate and finally crafted. Adventurers will be stuck with cheaply made broad and shortswords, while professional fighters might use two handed swords.