Rosalia was called into active duty to investigate a vampire rumor surrounding a number of killings in France. Confronted with the so called vampires, she learned that they were in fact affected by a rare disease which had shunned them from society. Rosalia intended to help them but by then she had called on the agents of the Inquisition, the Garduna, who made a move to eliminate the alleged vampire coven. Rosalia had no choice but to battle with their former employers who eventually took her life.

It was later revealed that as a teenager, Rosalia was raped and gave birth to a daughter who was taken from her and brought up in a convent. This child, Mariella eventually took her mother's place as the second Magdalena.