Little, Brown Book Group Irregular at Magic High School, Vol. 11 (light novel)

At the same that the leader of the USNAs elite magician unit, the Stars, traveled to Japan under the identity of an exchange student named Lina, the parasite incident wreaked havoc on the First Magic High School until Tatsuya and his friends saved the day and brought the incident to a peaceful conclusion. However, the parasite merely lost its first host and continues to wander this world. More importantly, its found its next host-a humanoid helper robot. After copying Honoka Mitsuis behavior and patterns, the parasite has been reborn as Pixie, vowing to follow and serve Tatsuya. After learning more about parasites from Pixie, Tatsuya