Helm: Bloodsoaked Mask

Armour: Official's Attire

Gauntlet: Bloodsoaked Manchettes

Leggings: X

Where To Find: 

(Click the link above to view the equipment and watch the getting video.)

The armor piece can be obtained by looting a corpse after gaining access to the Mountaintops of the Giants.

The helmet and gauntlets can be acquired by looting them from the ground in the Subterranean Shunning-Grounds.