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.
That is the only way he can 
survive in the netherworld
تلك هي الطّريقة الوحيدة لينجو في الجحيم
Da er in der Dämonenwelt
der einzige Mensch ist,
Básicamente porque es
el único humano del inframundo.
Básicamente porque es
el único humano del inframundo.
C’est l’unique moyen pour lui
de rester en vie,
È il solo modo per sopravvivere nell'Altro Mondo
Essa é a única maneira de
sobreviver no mundo dos demônios
А всё потому, что в Преисподней
он единственный человек.