Vladimir is a vampire of the Romanian Coven. He has blond hair and dresses in black clothes. He seeks revenge on the Volturi. He and Stefan show up to the Cullen house thinking they are challenging the Volturi, and are willing to side with the Cullens, only as witnesses.
Vladimir will be portrayed by Noel Fisher in the second half of Breaking Dawn.
Thousands of years ago, he and Stefan ruled the vampire world. They even told the humans in their city that they were vampires, instead of lying and saying they were saints (referring to St. Marcus Day in Volterra). Their castles were burned and their coven was destroyed by the Volturi. He and Stefan mention that 'We never put on white hats and call ourselves saints.' This suggests the idea that they were harsh rulers, and not afraid to say so. Neither he or Stefan are especially 'gifted'.
Vladimir and Stefan (of the Romanian coven) showed up uninvited to the Cullen household in Breaking Dawn, hoping that the controversy caused by Renesmee will finally destroy the Volturi. Vladimir called Alec as his opponent if it came to a fight. But, after having witnessed the growth of Renesmee, their hopes are vanquished by Aro's insight into the truth through Carlisle. There is no battle with the Volturi, though they are surprised at seeing their bitter enemies on Carlisle's side. Vladimir and Stefan seemed disappointed that they didn't get fight their rivals, but were happy to see the Volturi run away after the confrontation.
During their stay in the weeks prior to the arrival of the Volturi, Renesmee seemed to find their company fascinating. Bella, however, deemed them a bad influence after they colorfully described to the child how they would rip out the eyes of the Volturi from their sockets, and subsequently made an effort to limit Renesmee's exposure to them from then on. Jacob nicknamed Vladimir "Dracula One".
Vladimir is Slavic for "Rule with Greatness" or "Rule the World" (volod = rule,power and the suffix mir = great, peace, but also "world") perhaps referring to the fact that the Romanian's once ruled the world. And Vladimir mentions that he at least told the humans when he ruled that they were vampires, unlike the Volturi.
Note: Vlad Tepes (more commonly known as Vlad the Impaler) is commonly believed to be the first vampire.