A weapon scabbard was used to protect the sword from the elements so it would not rust etc. Plus people would not carry their sword ( or similar ) in their hand at all times. Usually made from leather. The use of this would be to where if you are not in combat you have your weapon sheathed, Either on your back or your belt, I would say make it to where a shield if you have one it will go on your back. If you put a sword in a sheath and drop it on the floor or put it in a chest it should also slow the decay of the sword alot.