The delinquents of Ishiyama High School either fear Tatsumi Oga or wish to defeat him, but the young fighter finds himself preoccupied with other matters—like tending to baby Kaiser de Emperana "Beel" Beelzebub IV, the son of the Demon Lord. Baby Beel's maid, Hildegard "Hilda," informs Oga that the...

Source: MyAnimeList