This is a list of characters from the light novel, anime, and manga series The Familiar of Zero.
Main characters
Louise
is introduced as a second-year student at the Tristain Academy of Magic. She is the third daughter of the Vallière family, an aristocratic family well known in Tristain. Louise is a very stubborn girl, but, as Henrietta mentions, her heart is pure. However, Louise is nicknamed "Louise the Zero" for her seemingly poor magic abilities that usually result in explosions, and she masks her insecurity and hurt feelings by a show of arrogance. Louise constantly defends her honor as a benevolent person; she states that it is her responsibility as a noble to ensure Princess Henrietta's safety and to see to her familiar's well-being. During the ceremony when all second-year students summon their familiars, Louise summons an ordinary human, Saito Hiraga. At first, Louise treats Saito as a slave or pet, having him wash her clothes and having him lay on a bed of straw. Louise quickly becomes jealous whenever Saito interacts with other girls and punishes him regularly by whipping him with a riding crop or blowing him up with her magic. However, as the series progresses, Louise begins to develop feelings towards Saito and eventually falls in love with him. In the 14th light novel, their relationship becomes deconstructive when, in order to counteract Joseph's invasion in Romalia, Louise had Tiffania erase her memories of Saito so that she won't be corrupted. Saito however restored Louise's memory by sharing his own via kiss, after which she develops a tsundere trait.
During Albion's invasion of Tristain, Louise discovers that she is an extremely rare Void Mage, an element descended from Brimir the founder of Harkeginia 6,000 years ago, which explains her consistent failure to perform other forms of magic. Her Void spell is 'Explosion'; when released, her powers can easily destroy armies, yet takes time beforehand to cast it. Louise casts off her status as an aristocrat in order to rescue her classmate Tabitha when she is taken prisoner by her uncle. After they return, the Queen of Tristain adopts Louise as a sister, which makes Louise second in line to the throne. Louise became a priestess, along with Tiffa, for the Pope's anniversary enthronement.
At the end of the fourth anime series, Louise and Saito defeat the Ancient Dragon and affirm their love for each other and are married. After the wedding, Louise uses her 'World Door' spell to go to Japan with Saito and visit his parents.
Louise is named after Louise de La Vallière, a French noblewoman who was the mistress of Louis XIV of France from 1661 to 1667. In 2007, Rie Kugimiya was nominated for Best Actress in a Leading Role at the first Seiyu Awards for her work in voicing Louise. She was named the third-most popular Rie Kugimiya character by an Anime! Anime! poll on Kugimiya's 39th birthday in 2018. Comic Book Resources named her the "Weakest Isekai Hero" and ranked her as the worst tsundere character, stating that she "is much more than just a textbook example of a tsundere" and that "she creates one of the slowest burning, most annoying build-ups to a relationship that ever had the misfortune of actually happening." She was ranked #4 in Da Vinci News' "Top 7 Pink-Haired Anime Heroines" poll, with one saying that they were infected with . Capsule Computers considered Louise unique in that while "[m]ost characters held a reasonable degree of emotion when speaking, [...] Louise was definitely the stand out character from a vocal standpoint." Her solo character CD, released on 10 October 2007, charted on #187 on the Oricon Singles Chart on 22 October. Her Princesse no Rondo album was released on 3 September 2008 and charted at #141 on 15 September 2008. Her character song album, Zero no Tsukaima Louise BEST, was released on 4 February 2009 and charted at #58 on 16 February. Her F drama CD album with Henrietta was released on 21 March 2012.