Rosanna Calvierri
Rossana Calvierri was the queen of a group of Saturnynians that were fleeing from a crack. She and her race has gone to Venice where she and her eldest son, Francesco, used Perception filters to appear human. They had come to the Italian city because of their marine nature, and to exploit the fear of the plague. The race set up a "school" under her headship, which gained notoriety in the city as a plague-free haven, and so it was an attractive proposition for fathers to bring their daughters to the school.
Once the girls were in the schools, their blood would be replaced with that of the Saturnyians, and they would be transformed into females of the species, ready to help drown Venice and form a new race with the other male survivors. Fortunately, The Doctor disabled her machinery, after which she disabled her perception filter and fed herself to her children in the canals. (DW: The Vampires of Venice).