F.I.S.T.: Forged In Shadow Torch

In order to do this, you will need to not only find the chests on the map, but you will also need to buy skeleton keys from the character Flip.

The first time that you meet Flip is when you are gliding down a shaft full of lasers in the power station. You will hear someone cry for help and you have to break barrels to find him. He will reward you with a key

The next time you meet Flip will be in the prison. You will need to find the keys and then return to him and unlock the cage. His location will be to the left of where you started. If you fast travel away from this location he will return to Joffre Street until the next big plot point

The next time you will meet Flip is in Joffre Street. He will sell a few keys. When you advance the quest past meeting Duke, he will then be gone in. A note will be in place. You will find him after the boss and the sewers to the right after breaking some barrels. He will sell a few more keys. If you fast travel away from this location he will return to Joffre Street until the next big plot point

When it says that he is in an underwater base area,
He will be in the arsenal, but you will not be able to reach him until you have access to the upgrade underwater charge that is found in the Underground Lake. Once you have this upgrade, return to where you fought the boss in the Underwater Base, and keep going to the right. This underwater cave will take you to the rightmost side of the map. Follow it and when you reach the arsenal, immediately, hug right into a vent and then travel north, he will be in more barrels. If you fast travel away from this location he will return to Joffre Street until the next big plot point

You'll have to get the skeleton keys (1 key per chest) from Flip's various locations. Remaining keys can be bought at Joffre Street.

There are 9 locations for the chests:

Abandoned Tunnel


Joffre Street


Old Town


Sewers


Power Station


Prison


Underwater Base


Arsenal


Coastal Fortress