Like the rest of the Daedric Princes in Skyrim, Clavicus Vile, the Prince of Wishes, Pacts, and Bargains, is a terrifyingly powerful being, and one who requests that the Dragonborn kill his companion Barbas. His quest is one of the odder ones in the game by a fair amount. It begins with him tasking the Dragonborn with accompanying a talking dog named Barbas in order to find the Rueful Axe, his Daedric artifact. Aside from the talking dog aspect, it's a fairly average goal.
However, once the player has retrieved the axe, they will be tasked with killing Barbas. Daedric quests that involve killing NPCs are nothing new in Skyrim, but this is the only one that requests that the player kill a dog, albeit a talking one. However, rather than a simple act of cruelty similar to what Molag Bal's evil mace quest demands in Skyrim, there is much more going on below the surface rather than a simple murder request.
Barbas is not simply a dog, as a player would likely infer from the fact that he can talk. In truth, he is the living conscience of Clavicus Vile. He is not only the prince's companion, but half of his existence. It is said that Clavicus Vile willingly split into two beings in order to never be lonely in his vast and powerful existence. His more impulsive side retained his identity, while his more moral, reasonable side became the dog known as Barbas. Without Barbas' influence, Clavicus vile is much more malicious and murderous in the wishes that he grants. Barbas may have issues as a Skyrim companion, but his goal of returning to Vile is a just one.
Skyrim - Clavicus Vile Would Be Even More Evil Without Barbas
This raises the question of why Clavicus Vile would want Barbas dead, considering that he is a part of himself. However, the fact that he is separated from Barbas is a major reason for why he wants to kill him. Barbas is Vile's conscience, the one who tries to convince him to act morally, or at least exercise some restraint. Without Barbas' good influence, he only considers the act to be getting rid of something that is holding him back. He fails to realize that by killing off Barbas, he would be permanently weakening himself because his existence would no longer be whole. In addition, even in his weakened state, his power is similar to the Daedric Wabbajack seen in Skyrim, only on a much larger scale. Obviously, that sort of power unrestrained is bad for Tamriel, and would cause major issues further down the line.
While the player has a choice of whether or not to kill Barbas in the quest, it is obvious that sparing him is the better option. With Barbas and Vile reunited, Vile will be more reasonable and less destructive in the use of his powers, which will ultimately benefit Tamriel overall. In addition, Vile will be whole once more and not lose his power. Although he will be aloof about it, Vile will thank the Dragonborn and leave them one of Skyrim's best Daedric Artifacts, the Masque of Clavicus Vile. This is the best ending for all parties. The Dragonborn gets an extremely useful artifact, and Skyrim will not have to deal with an unfettered Clavicus Vile.
The story of Clavicus Vile and Barbas is one of the more eclectic Daedric quests that the Dragonborn will encounter, but it is nonetheless a rewarding one. More than most Daedric quests, it truly does feel like the player is taking on a role in a mythical fable. Since Skyrim is a journey of mythological proportions in its own right, Clavicus Vile's quest fits perfectly as a chapter of that story.
