Nasubi is a subordinate demon serving under Hozuki within the administrative structure of the Japanese Hell, alongside Karauri. Despite his youthful, teenager-like appearance, he is an adult demon imp with a mixed heritage of imp and ghost cart lineages.

He performs various maintenance duties in Hell, including cleaning the banks of the Sanzu River. During one such cleaning task, a giant crab attacked souls, leading to Hozuki's intervention. Beyond routine work, Nasubi possesses significant artistic talent as a highly skilled illustrator. His abilities impressed Hozuki, who commissioned him to restore a deteriorating mural. During the planning for this restoration, Nasubi demonstrated knowledge of artistic styles and techniques.