The Blacksmith’s Hammer can be found at Bodilsburg Garrison. You’ll need to find the key, which can be looted from an elite enemy. Then, head up to the top floor of the tower and use the key to unlock the chest.
This shield is located beneath the Temple of Mithras. You’ll need to head down some steps at the center of the area then go through the crack in the wall and follow the tunnel until you reach a large underground room. Head to the left wall and move the second moveable object then head behind to grab the Briton Shield from the chest.
Hidden Ones’ Mask
This is located within the hidden Londinium Bureau. To get there you’ll need to climb up onto the ruins then jump down into the water that’s encircled by wooden poles. Then head beneath the water, shoot at the wooden wall on the left side and swim to the secret room area. To get to the chest, you’ll need to parkour and then destroy the stone barrier using an incendiary powder trap arrow or by shooting the pots behind the wall.
The Iron Cloud bow is found in a building east of the Amphitheatre. You can find the key on a barrel near the house to the right. Use it to unlock the door, then you’ll need to grab the second key from behind the moveable shelf and use that to unlock the chest on the otherside of the house.