A potential reward from the Daedric quest 'A Daedra's Best Friend'. [>>>Quest Spoiler Alert<<<] Killing Barbas during the quest will give the Rueful Axe.
Letting Barbas live and returning The Rueful Axe to the shrine of Clavicus Vile, will reward the Masque of Clavicus Vile instead.
- The original is normally turned in during the quest, so only the replica can be displayed.
- [>>>Quest Spoiler Alert<<<] If you killed Barbas and kept the axe, you only need to have had the original in your inventory for the replica recipe to be available. If you instead chose to return the axe to the shrine, the replica recipe will unlock at the Replica Station at the completion of the quest.