Final Fantasy XIV: Shiritsu Eorzea Gakuen

Alisaie is a high school student attending Eorzea Academy, an exclusive institution created by the merger of former rival schools the Academy of Light and the Academy of Darkness. However, frequent quarrels between the students prove that a bitter divide remains between the Class of Light and the Class of Darkness. Worried about the ongoing conflict, headmistress Tataru decides it's time for some bold solutions to raise morale. Let the school games begin!

(Source: Manga UP!)