Hyodo Issei es un estudiante de segundo año de la Academia Kuo, normal y corriente aunque perverso y lascivo. Lleva una vida tranquila hasta que una chica, Amano Yuma, le pide una cita. Claro que no se trata de algo normal: la chica es un ángel caído que buscaba asesinarlo. Sin salvación posible, Issei muere, pero inmediatamente reencarna en un demonio a las órdenes de Rias Gremory, una chica demonio de alto nivel que resulta ser la más hermosa y popular del instituto. Así pues, Issei queda atrapado en una guerra entre ángeles y demonios que viene de tiempos ascentrales. Pero no todo es tan terrible como parece...
Thomas Mann was a German novelist, short story writer, social critic, philanthropist, essayist, and Nobel Prize laureate in 1929, known for his series of highly symbolic and ironic epic novels and novellas, noted for their insight into the psychology of the artist and the intellectual. His analysis and critique of the European and German soul used modernized German and Biblical stories, as well as the ideas of Goethe, Nietzsche, and Schopenhauer. His older brother was the radical writer Heinrich Mann, and three of his six children, Erika Mann, Klaus Mann and Golo Mann, also became important German writers. When Hitler came to power in 1933, Mann fled to Switzerland. When World War II broke out in 1939, he emigrated to the United States, from where he returned to Switzerland in 1952. Thomas Mann is one of the best-known exponents of the so-called Exilliteratur.