The shield: Submersible Armament
The shield of Leviathan, the Submersible Armament, is built from three parts, each with three possible spots. Its special attack clears whole hordes, and a Carpenter power-up repairs it, as in Black Ops 4.

Where to build it
At the crafting table on the left of the Reception, or at the one up the stairs outside the Biodome.
The guard
In the Biodome: next to the little fence in the middle, on a metal post near the stairs of the Pantheon, or down in the Pantheon against a rock.
The pipe
Near Speed Cola, on the side of the Laboratory: on two barrels, against a crate by the door, or up the stairs of the generator on more barrels.
The viewport
Down from the power switch towards Reserve Soda: on a shelf, further along the corridor, or further in the tunnel.
