Caius

Caius is one of three vampires in Italy who live what Edward described as a very civilized and educated lifestyle. Caius has a wife named Athenodora who is not very well known and rarely leaves Volterra.

New Moon
As one of the leaders of the Volturi, Caius was insistent that Bella not be allowed to leave Italy alive. When it was determined that Edward planned to change Bella, Caius was disappointed, but Aro assured him that they would try again to persuade them to join.

Breaking Dawn
In Breaking Dawn, Caius, along with the rest of the Volturi, travel to Forks to destroy the Cullens. They had heard that the Cullens, particularly Bella and Edward, had created an immortal child, a creation they had outlawed. When they arrived, however, they found not just the Cullens defending the child, but many other vampires and a large number of werewolves. Aro, after learning that the child was actually half-human, tried to solve the confrontation peacefully. Caius, however, wanted a fight to break out. To accomplish this, he stressed the fact that the Cullens had allied with werewolves (something the Volturi did not tolerate) and had Irina, the vampire who had informed them of Renesmee, killed. His efforts failed, and Aro ordered the Volturi to leave peacefully once he was convinced to do so.

After the confrontation, Edward tells everyone that Caius has great fear of werewolves - not the shape-shifters of La Push - but "real" werewolves and had them hunted to near-extinction. This is because he was nearly killed in a fight with a werewolf two thousand years ago.

Physical description
Caius has very pale skin that is almost translucent. It is described as being similar to onion skin. His hair is shoulder length and as white as his skin. When he moves, it appears as if he is floating.

New Moon Movie
According to the BBC Jamie Campbell-Bower has been cast in the role of Caius.http://twilightersanonymous.com/news-blog