Well, this certainly looks like a K’tonian artifact but if you notice the grooves on the bottom, that means that this was actually made on a Jiyong potters wheel as an imitation of the K’tonian style of pottery. This is a replica, albeit a 700 year old, very good replica. I do happen to know a buyer who would be willing to pay you for it.
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.