18+ Zero no Tsukaima

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, Saitou, are bound to each other by the laws of magic for all eternity!

(Source: Seven Seas Entertainment)