Tenshi no Hane to Akuma no Shippo

Luca, a devil who entered a school for Angels, made a contract with a strange angel Haniel, and became a knight of the school. On a mission to stop the prophecy of a “great catastrophe,” he cannot leave the school and instead has to cooperate with others, like Lilith, an angel with red wings to figure out just what is in store for them.

(Source: Aerandria)