The second objective for the “Clandestine Trade Location” Exploration Codex task in Throne & Liberty requires you to interrupt the exchange between the Black Anvil and Arkeum legions.
Thing is, the game doesn’t really tell you where the exchange takes place. All it tells you is that it happens somewhere within the Black Anvil Forge, which is a large enough area. Besides, it also doesn’t tell you when exactly the deal takes place. It’s a fairly obtuse objective, really!
Read on and we’ll clear this all up. We’ll tell you where the exchange takes place and how to trigger it.
Clandestine Trade Location | Interrupt the Exchange Between Black Anvil/Arkeum Legion
For this Exploration Codex task, go to the northernmost part of the Black Anvil Forge in Talandre. You want to get to the exact spot marked above, which is just a smidge west of the Material Storage area. Make sure that you go at night, as the event doesn’t trigger during the day.

Once you’re there, wait in the area for around 5 minutes and you’ll see a yellow portal to the east. Bonia Naru’s Henchmen will spawn from the portal.

Then, a short moment later, a red portal will appear as well. This time, Arkeum units will spawn.

After both of these factions spawn, wait a bit more. They’ll talk and start hashing out the details of their deal. Keep waiting until you see a pair of chests spawn near them.

When you see the chests, it’s finally your time to interrupt the exchange! Attack Bonia Naru’s Henchmen and the Arkeum Legion warriors and defeat them all. Loot any remaining chests after defeating them, as well. They might disappear during the fight, but they should reappear when all enemies are dealt with.
So, there you have it, that’s the location for the Clandestine Trade Exploration Codex task in Throne & Liberty. You can now return to Waturu at the Herba Command Post of Herba Village to finish the task. That said, it’s a good idea to find the Black Anvil vendor while you’re still at the Black Anvil Forge.