The vampire coven known as the Volturi resides in Volterra, Italy. They are regarded as "royalty" by other vampires because they have lived for well over three thousand years and act as police, enforcing the rule that the existence of vampires be kept a secret from humans. They often send others to travel from Volterra to prevent overzealous covens and renegade vampires from exposing their species. They are guarded by several powerful vampires who have been collected for their powers and skills. Carlisle once stayed with the coven as a guest, but left due to his desire to avoid harming humans and created his own coven in the United States. At the end of New Moon, the Volturi discover that Bella, a human, has learned of the existence of vampires, and demand that she be made into a vampire as well, or else be killed. In Breaking Dawn, the vampire Irina goes to the Volturi and warns them that the Cullens have created an immortal child after seeing Edward and Bella's daughter, Renesmee, hunting not far from the Cullens' house. The Volturi coven proceeds to Forks to destroy Renesmee, but leaves once they realize that she is not a threat.
The Volturi leaders consist of Aro, who can read every thought a person has ever had once he has made physical contact, Marcus, who senses relationships, and Caius, who has no known power. Aro's wife, Sulpicia, Caius' wife, Athenodora, and formerly Marcus' wife, Didyme, who had the power to make others happy, also act as leaders. The Volturi guard consists of 32 members, including Jane, who creates illusions of pain; Alec, who is able to cut off the senses of others; Demetri, who can track anyone once he has the tenor of their mind; Chelsea, who can change emotional bondings; and Renata, who can make anyone feel distracted and wandering when they are near her (classified as a "shield"). The majority of the Volturi remain nameless throughout the series. There is also a human secretary named Gianna who appears in New Moon. Despite her hopes to become a vampire, she is killed by the Volturi by the events of Breaking Dawn. The Volturi have invited Carlisle, Edward, Alice, Kate, Benjamin, Zafrina, and Bella to join them, though all have refused.
I reckon that Dakota would be a brilliant choice for Jane, though I haven't really seen her play anything scary, so one wonders whether she could pull it off.
It has been said that no auditions have been held, and that the part has been offered out right to Fanning.. and negotiations are in process. I would be really please if she got the part, and I can't tell you how pleased I was that Hugdens from HSM wasn't auditioning for the part of the werewolf Leah!
Hopeful this starlight cast will draw even more people into watching New Moon.