Octopath Traveler - Battle-tested Weapons/Shield locations

There are 2 ways to acquire these weapons, one is post game guaranteed and the other is a low percent drop from certain 10 star NPC's. The guaranteed methods of obtaining are only available after completing a certain character's chapter 4. I will give the location of the NPC that drops and also the location of the weapon to purchase/steal from. The drop rate for challenging is 2% so it may take a while to get the items to drop.

Octopath Traveler - Forbidden Weapon Locations guide

The Forbidden weapons are a series of weapons that have good stats but a trade off in some form, I will show you where to get each of these and where you can purchase them. They cannot be stolen and have be purchased with Tressa.

They cost around 66-77k each but I suggest save scumming to get a 15-20k discount which is entirely random although Inquire/scrutinize can increase your chances in some towns. 

From what I have seen online some can be found in Therion's purple treasure chests, I do not know the location of the chests. Now includes shield.