Clavicus Vile is a daedric prince whose sphere is the granting of power and wishes through ritual invocations and pact. He is depicted as a small jovial fellow with horns protruding from his forehead and accompanied by his shape shifting hound Barbas.
He is described as likeing to have souls for the sake of having them and has worked through mortal representatives to gain what he desires. Clavicus Vile loves to make ‘deals’ with mortals that they later come to regret and supposedly granted vampires the ability to blend into mortal society undetected. His relationship with Barbas is not well understood and some believe Barbas to the ‘better half’ of Vile and not a separate entity due to Clavicus Vile being severely weekend by the absence of Barbas who houses a portion of his power.
Vile asked the Champion of Cyrodiil to retrieve the sword called Umbra for him, against the advisement of his hound Barbas who foresaw the ruin it would bring to the Prince. Once in Vile’s realm ‘Umbra’ escaped from the sword and cut away a piece of Clavicus’s power for itself. Clavicus was forced to change the walls of his realm to trap Umbra and prevent it from escaping with his power. Umbra, fearing Clavicus would return him to the sword used his stolen power to conceal himself in a city at the edge of the realm.
In the early fourth era Umbra learned a rift in the realm caused by the first ingenium would become wide enough for him to throw the ‘sword umbra’ through, lessening the threat posed by Vile. With the destruction of the first ingenium Umbra threw out the sword which landed in Mundus and caused the two dunmer who created the ingenium to be sucked into Vile’s realm. Umbra took them captive and agreed to release them if they built another ingenium which would tear away a piece of Vile’s realm large enough to allow Umbra to escape.
Clavicus Vile become trapped in a shrine dedicated to him within in a cave in Skyrim during the fourth era. After a disagreement with Barbas he threw him out into the mortal plane. Wishing to return to Vile, Barbas sought the help of the Dragonborn who upon setting up an agreement with vile to retrieve an ax was given the option to keep it if they killed Barbas.
His realm is an unnamed, tranquil countryside populated by deadly yellow daedra. Two artifacts are associated with Clavicus Vile:
Masque of Clavicus Vile: Improves speechcraft.
The daedric prince’s enemy is Ebonarm.
In Daggerfall he had the player assassinate a rogue Werewolf.
In Morrowind he asked the player to defeat a nord sorcerer named Sorkvild the Raven who had been terrorizing the village of Dagon Fel.
In Oblivion he asked the player to find and return the sword Umbra and sent his hound to assist the player but Barbas strongly encouraged the player not to search for it and to not give it back as it would "surely destroy him".
In Skyrim he agreed to take Barbas back if the player retrieved an ax and then gave the player the option to keep it if they killed Barbas.