Moongaze Ginji is a legendary figure known as a fast food grifter, or tachiguishi, who emerged from the black market immediately after World War II. He is celebrated as the finest of disciples in the thousand-year history of fast food grifting, yet almost nothing is known of his origins: his birthplace, birth date, and background remain entirely undocumented. He disappears after leaving behind countless legends, and his name becomes synonymous with the art of the soba scam.

His personality is elusive and philosophical. He treats his grift not merely as a means of getting a free meal but as a form of expression, famously describing his signature dish of soba noodle soup with a raw egg as an imitation of a landscape. This remark, spoken as he orders at a flimsy black-market soba stand, encapsulates his view that even a simple bowl of noodles can carry deeper meaning. He is calm, deliberate, and quietly rebellious, operating in the shadows of a society that has banned street-side eating. His motivations appear tied to a personal code of dissent rather than material gain; he is depicted as a dissenting hero who carves his name into the dark side of dietary culture.

In the story, Moongaze Ginji serves as a key ally and information source for the protagonist Koichi Todome. After returning to a changed Japan, Todome seeks out Ginji at an illegal soba stand, where the grifter provides critical intelligence while continuing his own scam. His role is that of a cryptic mentor who inhabits the underground world that the authorities have tried to suppress. He also shares ties with other fast food grifters, most notably Foxy Croquette O-Gin and Cold Badger Masa, forming a network of rogues whose stories weave through the larger Kerberos Saga.

His development is static; he is already a mythic figure by the time the narrative begins. His legend is told through his past exploits and his eventual disappearance, leaving behind only the lore of his moongaze soba and the philosophy it represents. His notable ability is his perfected grift: ordering a specific noodle dish with theatrical flair and then vanishing without paying, though the act is elevated to an art form that reflects the changing times and the fading traditional food culture of post-war Japan. His visual trademark, a black hat and an Inverness cape, has become an enduring symbol of the tachiguishi legend.