“The kio have a unique set of weapons and armor that they claim as their heritage. Only they may wear kio hauberks and wield kio swords. Anyone else with such equipment is hunted down and killed.” pg 206, top of second column of Arcanis 5e campaign setting guide.
“If you are not a kio you will not be given permission to purchase a kio sword or a kio hauberk no matter how much fame with the league of princes you have.” pg 229 first column, 4th paragraph.
So no one will sell you one and they will kill you for wearing one you loot in 5e…