A twin brother and sister who're polar opposites, and their work with the military.

Serena is a duke's daughter who is engaged to Finis, the head of the empire's pride, the Black Wolves Knights Order. Ever since she first saw his portrait, she became infatuated with him and has been fangirling...

A boy is resurrected as a demon girl in a parallel universe, where he's forced to fight against none other than his own childhood friend, who herself has sworn to wipe out every last demon in the realm.