Helm: Skeletal Mask

Armour: Raptor's Black Feathers

Gauntlet: Bandit Manchettes

Leggings: Bandit Boots

Where To Find: 

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

The Skeletal Mask and Raptor's Black Feathers are tucked away within Sage's Cave, concealed behind an illusory wall in separate chests placed side by side.

For the Bandit Manchettes and Bandit Boots, you can acquire them from Gatekeeper Gostoc stationed in Stormveil Castle.