You get it by completing the deadra prince quest of clavicus vile. It looks like a theatre mask and fortifies your personality by 20. However, in order to get it, you have to give up the most powerful sword in the basic game, Umbra. In comparison, when a deadric claymore does 31 damage, Umbra does around 33.
The armor rating for the Masque of Clavicus Vile is 23....
The shrine quest of Clavicus Vile. You must kill the bearer of Umbra before you can take it. Clavicus also wants you to return Umbra to him, in exchange for his helmet 'fit for a God', "The Helmet of Clavicus Vile". You can, however, refuse his offer and take Umbra, leaving behind a very unhappy Clavicus.
The book Tamrielic Lore was originally written for the game Morrowind, and so the items described in it are all found in Morrowind, but not all of them are found in Oblivion. They are: Lord's Mail, Ebony Mail, Spell Breaker, Chrysamere, Staff of Magnus, Warlock's Ring, Ring of Phynaster, Ring of Khajiit, Mace of Molag Bal, Masque of Clavicus Vile, Mehrunes Razor, Cuirass of the Saviour's Hide, Spear of Bitter Mercy, Daedric Scourge, Bow of Shadows, Fists of Randagulf, Ice Blade of the Monarch, Ring of Surroundings, Boots of the Apostle, Mentor's Ring, Ring of the Wind, Vampiric Ring, Eleidon's Ward, Staff of Hasedoki, The Bloodworm Helm, Dragonbone Mail, Skull Crusher, Goldbrand, Fang of Haynekhtnamet, Umbra, Denstagmer's Ring, Helm of Oreyn Bearclaw, and Daedric Crescent Blade. Oblivion players will recognize Spell Breaker, Ring of Khajiit, Masque of Clavicus Vile, Mehrunes Razor, Saviour's Hide, Bloodworm Helm, Goldbrand, Umbra and the Helm of Oreyn Bearclaw.
umbra is on a character named umbra in an ayleid ruin. i believe its just south of imperial city moat. its called vindaesel. It is part of clavicus vile's quest where you can return the sword to him or get his mask. goldbrand is boethias reward fo finishing his quest.
He returns to the shrine of Clavicus Vile. I hope you are not intending to date Barbas, though there is probably a mod that supports this feature.
As far as I know, the best weapon is actually Umbra. You can obtain it after killing Umbra herself in the Ayleid ruin Vindasel which is West of Pell's Gate. The sword is a quest item for Clavicus Vile, one of the Daedric shrines. You can however decide to keep the blade for yourself instead of taking Clavicus' upon completing the quest.
If you buy the Vile Lair download, I believe the Font of Renewal can cure vampirism. Otherwise, you need to go on the quest.
It is because the best enchantment is soul trap.It also does 13 damage. I prefer Goldbrand, which seems to be more of a good guy counterpart to Umbra. Since the creation of Morrowind these two swords have had a rivalry among players, and I chose Goldbrand... also because you cannot drop Umbra if you do not get it during the quest for Clavicus Vile. Umbra also seems to be more of an evil blade, and since i like good guy stuff, I chose Goldbrand.
The roads surrounding the imperial city, at one of the intersections will be a ruin, i can't remember the full name but it starts with a "v" go in there and you will find umbra at the very on of the ruins.
un masque (a mask), le masque (the mask)
faisal masque
First download the plug-in for the Lair. You should then access your world map and go to the Southeastern-most region of Cyrodiil and you will have a landmark there labeled "Deepscorn Hollow" which you can fast travel to.