Lidvia Lorenzetti is a Roman Catholic nun born in the Vatican who appears in the second season of A Certain Magical Index and its subsequent season. She is known within the Roman Catholic Church by the alias Mardi Gras, meaning Shrove Tuesday. Despite holding a high position in the Church’s hierarchy, she never sought further advancement; instead, she considered spreading her faith to the world to be a far more meaningful pursuit. This conviction drove her to extreme measures, as she was willing to do almost anything to propagate her beliefs.

Her defining trait is a deep, unshakeable devotion to evangelism, which extends to individuals whom the Church typically avoids or rejects, such as criminals, non-believers, and magicians from unrelated traditions. She possessed a unique talent for converting such people to Christianity, regardless of their background or prior allegiances. This ability was not a supernatural power in the conventional sense but stemmed from her persuasive demeanor, strategic insight, and skill in Catholic mysticism. She was also proficient in telepathy and large-scale tactical planning, allowing her to recognize latent potential in social outcasts and mold them into useful instruments for her goals.

Her primary motivation was to bring the entire world under the influence of the Roman Catholic Church, and she devised an ambitious plan to convert Academy City, the stronghold of science. To accomplish this, she used a powerful artifact called Pietro’s Cross. The scheme involved manipulating the environment, specifically by creating an artificial nightscape that blocked essential starlight, thereby disrupting the scientific city’s defenses. However, the plan ultimately failed when the blockage of starlight was counteracted, leading to a confrontation with the Anglican Church’s leader, Laura Stuart. Even when cornered, Lidvia remained defiant and resourceful. She survived a fall from a private jet during the ensuing conflict, though she was subsequently captured and imprisoned in the Tower of London by the Anglicans. Later, she managed to escape her captors and departed by jet, though she faced likely admonishment by the Vatican for her failure.

In terms of key relationships, Lidvia acted as the employer of the magician Oriana Thompson, with whom she collaborated on her Academy City scheme. She held a calm, collected demeanor, often appearing static and unflappable even in tense situations. Her development is centered on her unwavering faith and the consequences of her overreach; after her defeat, she expressed disappointment with the outcome but did not renounce her beliefs. Her story highlights the lengths to which ideological zeal can drive an individual, as well as the inherent limitations of even the most well-prepared magical operations when confronted by the combined forces of the Anglican Church and Academy City’s defenses. Overall, Lidvia Lorenzetti serves as a representation of a radical yet principled figure within the Roman Catholic faction, defined by her missionary zeal, tactical acumen, and the ultimately doomed attempt to expand the Church’s influence.