Clavicus Vile's Masque

Lore
Ever the vain one, Clavicus Vile made a masque suited to his own personality. The bearer of the masque is more likely to get a positive response from the people of Tamriel. The higher his personality, the larger the bonus. The best known story of the masque tells the tale of Avalea, a noblewoman of some renown. As a young girl, she was grossly disfigured by a spiteful servant. Avalea made a dark deal with Clavicus Vile and received the masque in return. Though the masque did not change her looks, suddenly she had the respect and admiration of everyone. A year and a day after her marriage to a well connected baron, Clavicus reclaimed his masque. Although pregnant with his child, Avalea was banished from the baron's household. Twenty one years and one day later, Avalea's daughter claimed her vengeance by slaying the baron.

The masque was owned by the Hero of Daggerfall as well, sometime around the year 3E 410. Obviously after dealing with Clavicus Vile. The Prince asked the hero to slay a certain werewolf. After the deed was done, the hero was rewarded with the masque.

Morrowind
The Masque is related to an Imperial Legion quest you receive at Moonmoth Legion fort. It can be found on a mage in Sorkvild's Tower, just east of Dagon Fel. See the Sorkvild the Raven quest for more information.

Oblivion
Masque of Clavicus Vile is the reward received from Clavicus Vile's Shrine quest.

The masque is enchanted with Personality +20 and is a unique helm that resembles the helmeted head of a man with a goatee beard and horned, Conquistador-esque helmet.

The problem with the artifact is that you are given a choice to take it or go against Clavicus Vile's wishes and keep the incredibly powerful sword, Umbra (a blade with an incredible amount of leveled maximum damage and Soul Trap 120 seconds on Strike). Note that if you can either formally deny giving him the sword by returning to the shrine, or you can just run off with it, without completing the quest. If you do the first Clavicus makes threats but never goes good on them.

Note also that if you just run off with the sword, it weighs 0 since its still considered a quest item, so you can carry more objects.

Skyrim
It is given as a reward for completing A Daedra's Best Friend.

Appearances

 * The Elder Scrolls II: Daggerfall
 * The Elder Scrolls III: Morrowind
 * The Elder Scrolls IV: Oblivion
 * The Elder Scrolls V: Skyrim