Deep within the demon realm rises a skyscraper known as Demon King Castle, the headquarters for the forces planning to invade the human world. Serving at the top are two newly appointed aides to the Demon King himself. Vilush is a lazy, free-spirited slacker who will do anything to avoid work, while Rio is a serious and promising young hope of the demon army, strictly devoted to his duties. The comedy unfolds almost entirely during the periods when the terrifying, stern-faced Demon King is away from his throne, leaving his two contrasting aides to their own devices.

The core dynamic is established through their petty arguments and absurd conversations. Vilush constantly seeks ways to slack off, which Rio condemns as following a pathetic path of a aide, yet Rio often gets unwillingly dragged into Vilush's schemes. The supporting cast includes other members of the demon army, such as Jasper, the captain of the Demon King's First Unit, a man who prides himself on being the strongest and most solitary, but is secretly beloved by his troops who see him as an older brother figure.

Several narrative arcs highlight the series blend of workplace comedy and supernatural fantasy. In one storyline, the pair are forced to participate in the First Unit's monthly training session that goes past quitting time, much to Vilush's dismay. When the captain confides that he feels his soldiers should fear him instead of looking at him with warm eyes, Vilush and Rio have to navigate his misguided self-perception. Another arc centers on the castle's general admission day, an ancient tradition where sneezing at the wrong moment once led to an aide being beheaded. When Vilush is caught hiding behind the throne by a child, he panics, tries to bribe the child, and eventually strips off his clothes to blend in with commoners. In a desperate move, he even seats the child on the throne, forcing the rule-abiding Rio to react, which nearly results in both of them being executed before it is revealed that beheading was merely a metaphor for getting fired.

The series is a gag comedy focused on dialogue and character interaction, using the grandiose setting of the Demon King's Castle as a backdrop for mundane yet absurd workplace problems. Serialized in Jump Square, the first volume was published in March 2026.