From Skyrim Wiki
There is a rare chance on low health that the mask will spawn a spectral dragon priest who will summon his own Frost Atronach to fight by your side. The mask can be improved if the Dragonborn has the Daedric Smithing perk.
- Obtained once all the other Dragon Priest Masks have been collected and placed on the mask altar in Labyrinthian with the help of the Wooden Mask.
- Konahrik ( ) means "warlord" in Dragon language.