From Hyper Parfait:

After World War III, the Führer established the Unified World Government. Anything considered as damaging to the creation of the “Perfect World” is eliminated, such as people with disabilities, believers of a different religion, those that are considered as “traitors”, and so on.

The Black Rose is the personal protection guard unit of the Führer. Luka Ogami, the top graduate of the academy of unified army officers, joins the Black Rose…. to save the world.

From The Zero Alliance:

At Seirei Academy, a series of mysterious demonic ceremonies have been taking place and the transfer student, Yuriya Yuuki is suspected by his classmates. One evening, from his dormitory window, Yuriya sees a girl wandering outside and follows her. Once outside, he encounters a book which allows him to summon the demon Belial, whom invites Yuriya to enter into a contract with him…