The Familiar of Zero

In a world where sorcery reigns supreme, bumbling witch-in-training Louise Francoise le Blanc de La Valliere is known by her classmates at the Tristain Academy of Magic as “Louise the Zero.” During an important coming-of-age ritual, when each student must summon a lifelong familiar, Louise proves herself klutz when she mistakenly conjures a teenage boy from Earth. Now, whether they like it or not, Louise and her unwilling servant, Saito, are bound to each other by the laws of magic for all eternity! (Source: Seven Seas Entertainment)

A series of 4-koma comics featuring super-deformed versions of the cast of Zero no Tsukaima.

War rages on between Tristain and Albion, and the inept mage Louise has a new top-secret mission. But before she can take on the enemies of her country, she’ll need to get past an even tougher opponent — her family. Can Louise convince her dismissive older sister that she’s not a Zero anymore? Saito and Siesta get dragged along for the ride, and seeing Louise at home in her family’s extravagant palace makes them both rethink the crushes they’ve been nursing. With social status pushing Louise and Saito apart and raging hormones pulling them together, a love triangle like this can only end in explosions! (Source: Seven Seas Entertainment)

A spin-off side story of Zero no Tsukaima featuring Tabitha as the main character.

Kalina's dream was to become an elite knight, just like the one who saved her when she was little. But women aren't allowed to join the elite Mage Guards. So she changed her name to Kalin, dressed up like a man, and went to the capital, where she got into an argument with a nobleman named Centurion that escalated into a duel! Kalina was accepted into the Mage Guards as an apprentice. But that annoying Centurion was assigned to be her superior and her roommate, too! Can she hide her real gender, and become the knight that she dreamed of? (Source: MF Bunko, translated)

A side story/spin-off of "Zero no Tsukaima" Featuring Tabitha