Vicente Valtieri is a breton assassin and member of the Dark Brotherhood living in the Cheydinhal Sanctuary. He is the first contract giver for the player and despite being a vampire is arguably one of friendliest characters in the game.
Vicente has been in the Dark Brotherhood for over 200 years and knows alot about it's past. He became a vampire while on an expedition in Morrowind 300 years ago in Vvardenfell and hints at knowing about the Count of Skingrad being a vampire:
"The Count of Skingrad is not all he seems. Let's just say I'm not the only one who enjoys his evenings."
Vicente offer's to pass his 'dark gift' onto the player if they desire after he deems them worthy. He also carries a note on him to Ocheeva berating Antoinetta Marie's cooking and expressing his aggravation towards her use of garlic which he has a weakness to:
"Damn that young fool Antoinetta and her experimental recipes! As if the stench of her cooking weren't bad enough, last week she made a particularly offensive dish consisting of mandrake, onions... and garlic! Garlic! I have told her repeatedly of the danger this plant poses to me, but she has obviously not heeded my warnings.
It is strange, this reaction I have to garlic. In all my wanderings, in all my research, I have never encountered another vampire thusly affected. It is true that some popular lore holds that all vampires have an inherent weakness to garlic, but this is simply not the case. My situation, as far as I can tell, is unique. If I were to somehow come into contact with garlic, if it in some way came to be on my person, the results could be catastrophic. I would most certainly suffer from a loss of strength and stamina, and fear my resistance to magic would be nearly completely nullified.
So please, Ocheeva, as mistress of this Sanctuary, I beg you to keep Antoinetta on a tighter leash. I love her as a Sister, of course, but can not be held accountable for my actions should she continue to disregard my own personal safety. The Tenets clearly state that one family member may not kill another; but I don't need to remind you there is no restriction against draining Antoinetta of a few pints of precious life's blood."
Vicente Valtieri is one of the Brotherhood members to be killed during the purification.