Originally from the 1920s, Sotheby is a wealthy young lady that specializes in potion making. She is very curious and knowledgeable, but lacks common sense. She has a butler called Mr. Karson. After meeting Sonetto, she agreed to help her and Vertin in escaping the enemy and curing mass hallucinations caused by the impending "Storm". After being rescued from the "Storm", she joined Vertin's group.
Sotheby is voiced by Harriet Kershaw in English and Itou Miku in Japanese.
