The charming incarnations of the seven deadly sins—brothers Lucifer, Mammon, Leviathan, Satan, Asmodeus, Beelzebub, and Belphegor—can never seem to keep out of mischief. They are demons feared across the Devildom, but, at the Royal Academy of Diavolo, one human transfer student has captured their collective hearts. Whenever the brothers miss them, they engage in ridiculous antics to keep themselves entertained, and they even drag others into their neverending shenanigans.