Alec is a member of the Volturi and is one of the highest ranked guards. He has a sister named Jane. In the New Moon film adaptation, Cameron Bright has been cast to play Alec.
Aro is one of three vampires who lead the Volturi. He is widely accepted as the overall leader of the Volturi, and possesses the gift of tactile telepathy, the supernatural talent to ascertain the thoughts of a person with a single touch. Michael Sheen has been cast to play Aro in the film adaptation of the series.
Caius was born about 1000 BC, and at some point became a vampire. He later joined the Volturi, along with Aro and Marcus. It is unknown if Caius ever met or known Didyme, Marcus's wife and Aro's genetic sister, or if he knows that Aro killed her himself. Later two female vampires joined the Volturi: Sulpicia and Athenodora, who both were cousins. Athenodora later became Caius's wife. Some 2000 years before Breaking Dawn, he was nearly killed by a werewolf in a fight, and never got over it, so he hunted werewolves to near extintion. He also participated in the extermination of the Immortal Children, which he deemed to be dangerous.
Demetri has an olive complexion with a chalky pallor, and dark hair that reaches his shoulders. He is described as tall and lean. He is perceived to be very polite. His special ability is tracking. He catches the "tenor" of a person's thoughts, and is drawn to it. It is believed that he would not be able to track Bella, since she is protected from mind-based abilities.
Bella describes him as "very big, tall, and thick", and that his size reminds her of Emmett Cullen. He is described as having an olive complexion which looks odd combined with his chalky pallor. He also has short, cropped, black hair. He is not gifted, unlike most of the Volturi. It is assumed that he is kept in the guard because of his immense strength.
Jane is a sadistic guard of the Volturi and a pet of Aro's. She seems rather bitter and easily justifies inflicting pain on anyone with her power. Jane and her twin brother Alec reside in Volterra, Italy. The Volturi had their eyes on Jane and Alec as potential people to change back when they were still human, but were waiting until they were older to change them. When frightened humans tried to burn the twins at the stake because of suspected witchcraft, Aro stepped in. Because of all she went through, she gained her power of being able to voluntarily inflict an illusion of antagonising pain. Aro was forced to change them while they were still young and kill every human who tried to burn the twins. Jane has since become one of the prize members of the Volturi Guard.
Marcus has the ablility to recognize relationships. Stephenie Meyer described Marcus's powers as the following: "Marcus’s gift is actually quite valuable in the hands of someone who knows how to use it. For example, imagine Marcus on the battle field. He sees the binding ties between the enemy the guard faces. He can tell who the leader is just by watching the way the others are tied to him or her. He can see how to destroy the resistance simply by picking off a few key people. He doesn’t just see romantic relationships, but also ties of family and friends, loyalty and devotion. He can tell if any given person would die for another. Off the field of battle (as the Volturi rarely leave their home), Marcus’s gift is valuable politically (for lack of a better word). It’s an amazing gift in a diplomatic situation. Plus, when you’re sitting on an empire, it’s nice to be able to see when someone’s loyalty starts wavering. Or if anyone is getting too fond of anyone else. Can you see the potential now? Marcus didn’t get where he is with some fluff skill." When Marcus first encounters Bella and Edward, he is surprised by the intensity of their relationship. He shares this information with Aro mentally and never utters a single word.