Bianca is a human-turned vampire who worked for the Volturi as a secretary in Breaking Dawn.
She brought a note sent from Carlisle to inform them of Bella's transformation into a vampire and her addition to the Olympic Coven. Aro noted that 'Carlisle' was misspelled before signalling Felix and Demetri to remove her. She was forcibly dragged out of the chamber kicking and screaming. Since she was determined to become vampire, Aro changed his mind and had Demetri turn her.
After her transformation, Bianca fled from Italy since she feared the Volturi and became a European nomad.