Boukyaku Go no Aletheia

Aletheia, a member of the Magic Corps, 1st Division, possesses a rare magical power known as “Forgetting Magic.” Even the notoriously cold and ruthless Division Commander Christoph treats her with kid gloves, and she finds comfort in their ambiguous relationship. However, something is about to shatter her peaceful life…!?

(Source: Hana to Yume, translated)