Clavicus Vile (Quest)

One of Clavicus Vile's worshippers has told me that in order to summon the Daedra, an offering of 500 must be given to the statue. [Must be level 20 to begin this quest.]

Walkthrough
After giving Clavicus the offering of gold, he speaks of a sword he wishes to recover, "Umbra." When the statuette of Barbas is given, continue on to the next item on the agenda.

After walking a bit, the statuette will speak, giving a short story before pleading to not return the sword to Clavicus Vile.

Pell's Gate
The quest says to start in Pell's Gate, a small settlement. By talking to Irroke the Wide he will reveal that his old apprentice, formerly known as Lenwin found the sword Umbra which tainted her, she began to name herself after the sword. She joined a group of mercenaries to satisfy her lust for blood but Irroke the Wide later heard that wasn't the case anymore.

Vindasel
The treasure is actually to the west, in an Ayleid ruin, Vindasel. The ruin is not deep, but there is a crusher and a gas trap inside, so remain vigilant.

Upon reaching the destination, it will be clear that Umbra is not only the name of the sword, but also the person that wields it (or rather, an alias the wielder assumes).

Speak to Umbra and hear her two choises. Either leave her alone and walk away or fight her and take the sword from her. Killing Umbra can be hard and retrieve the sword.

Shrine of Clavicus Vile
When returning to the Shrine, the choice of either keeping Umbra or giving it to Clavicus for reward will be present (a dialog will appear, asking for the sword).

If the choice is made to return it, the reward will be the daedric artifact, Masque of Clavicus Vile. The quest will finish either way, so even the decision is to keep Umbra, the Hero can still do the quest at the Shrine of Hermaeus Mora.

Trivia

 * For tips on defeating Umbra, see the Umbra article.
 * If one decides to keep the sword, the followers of Clavicus will attack him/her to give him the sword and gain fame for himself and it will no longer be weightless. It will then have a weight of 45.
 * By choosing to side with Barbas (Clavicus Vile's dog) when he speaks through the Statuette of a Dog (which appears in the inventory upon starting the quest) and not kill Umbra, the dog in the statue completely disappears.

Bugs

 * There is a bug where either keeping or giving the sword to Vile, the game freezes 5 seconds later. To avoid this, simply keep Umbra and don't return to the shrine. Unfortunately, this will not allow one to do the Shrine of Hermaeus Mora quest. This bug can be defeated by first finding the Shrine of Hermaeus Mora, then as soon as Clavicus Vile stops talking fast travel to Shrine of Hermaeus Mora and activate the statue as fast as possible.
 * It is possible to go to Vindasel and kill Umbra even if the player isn't level 20 or hasn't given an offering. One can then take the sword and finish the quest without starting it. (Not truly a bug, just a way around part of the quest.)
 * Solution: One way to avoid the bug is by going to Vindasel and killing Umbra before the quest, then going to the shrine and starting the quest. If the quest has already been started and this bug is active, he/she can get past it (regardless of giving the sword or not) by fast traveling to Cheydinhal East gate immediately after he stops talking and the quest updates. The dog statue should start talking, then be removed from the player's inventory without freezing. Note: The dog statue is what causes the bug. The dog statue being removed is what makes the game freeze up, but fast traveling to Cheydinhal East Gate removes the dog without freezing.