Bianca is the younger sister of Alfredo and only daughter of the couple Viscount Vittorio and Viscountess Patrizia Martini. She is a tomboy whose talents are dancing and playing the piano. Bianca and her big brother grew up at the Martini mansion in Piedmont. They enjoyed a happy, peaceful life with their parents until a great tragedy struck their family. Maurizio and Grazela Martini, the siblings' relatives who coveted all the treasures of Viscount Vittorio (especially the Martini medal), burned the Martini mansion. Bianca and Alfredo managed to escape with the Martini medal during the fire, while their parents were burned to death. Maurizio and Grazela hunted the orphaned siblings for the Martini medal. They even put the blame for the fire incident on Bianca and Alfredo's heads, making the siblings wanted by police. Bianca told Alfredo to cut her long, curly, blonde hair because of these reasons, hoping she would not be recognized by Maurizio and Grazela.

A month after the tragedy in Piedmont, Bianca and Alfredo stumbled across a farm village. During this time, Bianca could no longer walk because of tiredness. A farmer saw the siblings resting along the road and rescued them. Soon, the "God of Death," Luini, appeared in the farm village. In order to protect Bianca, Alfredo decided to sign a contract with Luini and go to Milan to work as a chimney sweep. Bianca was left behind in the farm village.

Soon after Alfredo went to Milan, Bianca was captured by Maurizio and Grazela. Knowing that Alfredo was in Milan and the Martini medal was with him, the evil couple took Bianca hostage to forcefully get the medal from him. Romeo and the Black Brothers then saved Bianca from the hostage-takers and brought her at San Babila Church, where she was reunited with her older brother Alfredo, who at that time was already suffering from tuberculosis. After the reunion, Bianca became a special member of the Black Brothers.

Bianca and Alfredo victoriously cleared their tarnished names and reclaimed their inheritance on the day that they met with the King of Italy. The king was convinced that the Martini siblings truly did not murder their own parents. The following day after the meeting with the King of Italy, Alfredo passed away. During the period of mourning for Alfredo, Bianca went to Romeo, who became very depressed because of what happened. She said comforting and encouraging words to Romeo and even hugged him. After hearing from Bianca, Romeo gained the strength to accept Alfredo's death and the request of his fellow Black Brothers to become their new leader.