Quanzitta Marison is a recurring character in the anime series Madlax. She is a mystic who lives in a native village called Doaiho, located deep within the combat zone of the war-torn country Gazth-Sonika. She has a dark-tan complexion and pale, silvery-blond hair, and written descriptions of her eye color vary between reddish and brown. Because she and her servant appear physically distinct from the other people of Gazth-Sonika, it is possible that they descend from the ancient Elies civilization.

Her background centers on her role as a keeper of sacred knowledge. Quanzitta is the owner of Thirstari (also rendered Thirstary), the third of the three Holy Books that are central to the series' supernatural mythology, and she is one of the few people in the world who can read the Elies script and the Saruon language in which the books are written. This literacy, together with her familiarity with the books' history, makes her the most authoritative living source on the conflict surrounding them.

In personality, Quanzitta is presented as calm, composed, and self-possessed. She governs her household with quiet authority and is respectfully addressed as Lady Quanzitta. She receives the travelers who come to seek her out with a measure of graciousness, and once she judges that the moment has come, she speaks plainly about dangerous truths rather than guarding them indefinitely. Her personal history and inner life are not explored in great depth, and the series keeps her somewhat mysterious, presenting her more as a figure of wisdom than as someone shaped by an individual struggle.

Her motivations are tied to her position as guardian of knowledge. The narrative does not give a detailed account of her private aims, but within the story she acts to preserve the knowledge of the Holy Books and to support those who would prevent that knowledge from being misused. Her assistance comes at a critical point: when Madlax and Margaret Burton go looking for her because she supposedly knows about Margaret's book, about Enfant's involvement with it, and about the criminal syndicate Enfant itself, Quanzitta confirms their search and tells them that Enfant, led by its mastermind Friday Monday, plans to plunge the entire world into a total war beginning with Gazth-Sonika. She also reveals that Monday's supernatural powers are connected to the three ancient books, one of which belongs to Margaret. This information provides the protagonists with the understanding they need to continue their fight.

Her most significant relationship is with her servant Nakhl, who lives in Doaiho Village and attends to her. Through Nakhl, Quanzitta's influence extends into the later stages of the story: after Madlax falls into despair following the death of Vanessa Rene, Nakhl helps restore Madlax's will to live so that she can rescue Margaret, acting in the spirit of Lady Quanzitta's household even as the action leaves the village behind. Quanzitta's direct encounters with Margaret and Madlax are brief but decisive, and her credibility allows them to trust the difficult truths they learn from her.

Quanzitta does not undergo a personal transformation over the course of the series; she functions as a stable guide figure whose importance lies in what she knows rather than in any change she experiences. Her notable abilities are primarily scholarly and mystical. Beyond her mastery of the Elies script and Saruon language, she possesses a deep understanding of the Holy Books, the rituals associated with them, and the mysterious power known as the Gift, which the books are instrumental in using. As the bearer of Thirstari, she holds one of the three sacred volumes and therefore occupies a unique place in the mythology of the story, even though she remains on the periphery of its action.