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 Valtieri is one of the Brotherhood members to be killed during the purification.