Suzuki Iruma (voiced by Ayumu Murase) was sold to the demon king Sullivan (voiced by Takashi Kuroda) by his parents. Unexpectedly, Sullivan doted on Suzuki, who was a human, because he had no offspring. As Suzuki grew up, Sullivan sent him to the demon school Babils for further study. In order to survive in this school full of demons, Suzuki's first task was to hide his human identity. The carefree and reckless Valak (voiced by Ayaka Asai), the outwardly queen-like Asazile (voiced by Saori Hayami), the seemingly smart but actually stupid Asmodeus (voiced by Ryohei Kimura), the strong physique and big nerves of Subnok (voiced by Takuya Sato), the gentle and kind Suzuki soon made good friends at school.