Cecile Lafitte is a teacher at Saint Marguerite Academy, serving as the homeroom instructor for the class attended by Kazuya Kujo, Victorique de Blois, and Avril Bradley. Physically, she is a small woman with a youthful, babyish face, fluffy light brown hair, and large round glasses which have become a defining feature of her appearance. She typically dresses in light-colored clothing such as a pale yellow blouse with ruffles and a high-waist pencil skirt. Before becoming a faculty member, Cecile was herself a student at the same academy, a fact that gives her a unique connection to the institution and its history.

In terms of personality, Cecile stands out for not fitting the typical mold of a strict or authoritarian instructor. She possesses a friendly and approachable demeanor, often behaving in ways that seem less mature than her own students, which reflects her relatively young age. Despite this, she is capable of showing a strict side when the situation calls for it, occasionally scolding Kazuya when he finds himself in trouble, often while taking the blame for incidents involving Victorique or Avril. One of her most notable traits is her extreme timidity, particularly when confronted with ghosts, scary stories, or the supernatural. She has a well-known habit of becoming so frightened that she will throw off her glasses and flee from the source of her fear, or even faint on the spot. This reaction is ironic given that she possesses considerable knowledge about the urban myths and legends of the fictional country of Sauville and has a personal interest in the supernatural. Her attempts to prevent Victorique from using an empty smoking pipe, insisting that the girl is merely pretending to be an adult, are consistently unsuccessful.

Within the story, Cecile plays a crucial supporting role as a gentle guardian and caretaker for Victorique, who is confined to the academy's grounds. Before the arrival of Kazuya, she was responsible for bringing class notes to Victorique in the botanical garden where the girl resides. Recognizing a connection between the two students, she instructs Kazuya to take over this task, which effectively serves as the catalyst for their first meeting and subsequent partnership. This act demonstrates her quiet but effective way of looking after her students' well-being. She is one of the very few people in Victorique's life whom the brilliant but often abrasive girl does not actively dislike; Victorique considers her a friend, even if she sometimes teases or bullies her. Cecile has a network of key relationships outside of the classroom as well, including a close friendship with Sophie, a maidservant at the school, with whom she often spends time. She also carries a deep emotional bond with a deceased former classmate named Millie Marl. As part of a promise made long ago, Cecile dutifully tends to the primroses that Millie had received, a quiet ritual that connects her to a poignant memory from her own school days.

Cecile's devotion to her students is a consistent driver of her actions. When the transfer student Avril is forced to return to Britain, Cecile demonstrates her deep care by holding an entire final lesson just for her. Her development is largely tied to the sweeping events that affect the world around her. As the war reaches the kingdom of Sauville, the academy is forced to close, leaving Cecile unemployed. During this period, she goes to live with her friend Sophie. Despite this disruption, her fundamental nature as an educator remains intact, and in the aftermath of the conflict, she returns to the school, ready to welcome students once again when it reopens. Regarding her abilities, Cecile does not possess any deductive or physical prowess akin to the series' main characters. Her notable abilities lie in her steadfast empathy, her patience in caring for an isolated and difficult girl like Victorique, and her extensive knowledge of the academy's lore and local legends, which she shares with her students.