Magical cloak that acts as armor. Protection against normal and magical attacks as well as holy spells. Gives creatures who are harmed by light and sunlight immunity. Give wearer the ability to become invisible at night. Sentient and cursed. See full description for details.
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.