Katsute Mahou Shoujo to Aku wa Tekitai Shite Ita.

かつて魔法まほー少女しょーじょと悪あくは敵対てきたいしていた。。

The manga centers on Mira, the clever brains behind an evil organization that invades and destroys everything in its path. One day, a magical girl named Byakuya Mimori decides to stand up to the organization, and Mira falls in love with her at first sight. (Source: ANN)