Legion of the Dead armor set

The Legion of the Dead armor has a very high strength requirement and can be found in the Dead Trenches. The armor, boots and gauntlets can be found in various sarcophagi as you make your way towards the Anvil of the Void. Eventually you will come across a locked metal door. The door to the right of this locked metal door called an "Ominous Door" is in the room where you will find the final piece of armor for this set. The Helmet is in the altar at the far end of the room, but once you take it, you will be attacked by all of the Legion spirits in the room.

Donning the entire set of armor is required to initiate the Gangue Shade unmarked quest. Activating the Gangue Shade Altar (found in the room behind the "ominous door") while the entire harness of armor is equipped by the primary character summons the Gangue Shade, which appears to be a fairly garden-variety shade with a unique name. When defeated, it may drop no loot at all or a randomly selected leveled item (often medium armor of some type). Neither the encounter nor the armor triggers a quest or journal entry, although a Gangue Shade codex entry does appear.