Athenodora was one of the oldest vampires in existence. Sometime around 500 AD, she was transformed into a vampire when she met Caius during the Romanian Coven's attack that dominated his territory, and traveled with him until they met Aro and Marcus. Together, they formed the Volturi coven.
After the loss of Marcus's mate and Aro's sister, Didyme, she and Sulpicia- Aro's wife - became prisoners in their tower, though they are accompanied by Corin, who frequently uses her gift to make them feel content with their situation. She and Sulpicia rarely leave the tower, even during important times of vampire history, such as the hunting of the immortal children.
She was first seen in Breaking Dawn where she, along with Sulpicia, and the entire coven arrive to Forks to eliminate the Cullens for creating an immortal child, which turns out be a misunderstaning. Athenodora and Sulpicia remained silent during the confrontation and watched the execution of Irina for committing a false committment. Even though, they saw how sorry Irina was, and Athenodora was displeased how Caius executed someone for a misunderstanding. After the Cullens were proven innocent, Athenodora and Sulpicia return peacefully to Volterra where they would remain locked in their towers.
In Rising Dawn, she and Sulpicia were called again by their husbands to destroy the British Coven for forming a rebellion. Near the end of the battle, Athenodora saw her mate die at the hands of the Denali Coven. She didn't even care since she was held prisoner and that he never cared. She decided to meet her end when Astrid and Joel ran towards her and tore her to pieces.
Caius is Athenodora's mate. They met and began travelling together as nomadic couple before they formed the Volturi with Aro and Marcus. It is assumed she remains totally loyal to Caius. She remains in the tower, and is so closely guarded in Volterra she has become a prisoner. However, Corin is sent by Caius to keep her company. Corin's gift allows Athenodora to feel content and happy despite her prison-like circumstances. Athenodora stays in the tower and the few times she does leave, she never leaves without him and he has her heavily guarded, suggesting the two depend on each other.
Sulpicia is Aro's wife and Athenodora's company in the Volterra tower. The two of them spend the majority of their time together as they are both trapped in the tower in Volterra and well-guarded by the Volturi guards. Because of Corin's gift, however, they are content and perfectly at ease with their situaton. With Corin as part of their personal guard, the wives have never objected to their incarceration.
- Breaking Dawn
**Breaking Dawn - Part 2