Familiar: a knight (newly appointed), Hiraga Saito
Age: 16
Birthday: August 6
Height: 153-156 cm
BWH: 76-53-75
Favourite food: Cookberry Pie
Hobbies: knitting
Special skills: horseback riding
Hates: frogs, Kirche
Runic Name: Louise the Zero (Zero no Louise)

Louise Françoise Le Blanc de La Vallière is the main female character. She is a second year student at the Tristain Academy of Magic and a terrible mage who is often scorned by her fellow classmates. Because every spell she casts fails, she is nicknamed "Louise the Zero" after her zero percent success rate. She is the third daughter of the noble family La Vallière who owns the north-eastern territory of Tristain. Even though it takes her a long time to admit it, she quickly falls in love with the familiar she summons, a human by the name of Saito.

She later finds out that her type of magic is the fifth type known as void magic.
Zero no Tsukaima F:
In the final episode, she gets married to Saito and the couple goes on a holiday to Saito's world using her World Door spell.
Louise was named after Françoise Louise de La Baume Le Blanc; a mistress of Louis XIV of France from 1661 to 1667. She later became the Duchess of La Vallière and Duchess of Vaujours in her own right. She also had interactions with the real life counter parts of other Zero no Tsukaima characters such as princess Henrietta, Guiche de Gramont, and Colbert.
(Source: Wikipedia, edited)