Due to very bizarre circumstances, the human boy, Suzuki Iruma, ends up in the netherworld. He is keeping the fact that he is human a secret and attends the Demon School Babyls. Because he is human, he cannot use magic so he had been using the Gluttonous Feeder Ring to get by in school. But then one day, the ring started to speak! Why, though? Iruma then meets the incarnation of the ring who calls themselves Alicred, AKA Ali-san.
Tremble at the sound of 
black wings as we take flight
ارتعشوا من صوت أجنحتنا السّوداء ونحن نحلّق
Tremate al batter di nere ali mentre decolliam
Trema com o som das asas negras
Крылья чёрные дрожат, когда летим,