Although he lives away from home due to his father's extreme nature, he possesses wealth that transcends common sense. He is a tycoon capable of buying an entire city block to convert the basement into a hideout and creating a vast artificial garden; he is wealthy enough that gifts like a racetrack or a ranch are actually feasible. He is the boss of the villainous organization "Fake KNIFE" and a major supporter of SPOON. When the real villain organization KNIFE went dormant, high-ranking government officials pushed for the dissolution of SPOON. To provide SPOON with a reason to exist and maintain its operations, Osu organized Fake KNIFE. Because Osu's family has such strong influence that even high-ranking officials have to back down, they are forced to acknowledge SPOON's continued existence despite knowing KNIFE is a fake. He has slight dark circles under his eyes and is physically frail. He is incredibly kind. More than a few people, including Dana and Naga, have had their mental wounds healed by Osu. Dana calls him an angel, Naga associates him with angel wings and a halo, and other characters frequently mention his warm and gentle nature. He is a truly kind-hearted person with no hidden darkness or ulterior motives.

A member of Fake KNIFE, where Osu is the boss. He was originally a doctor and lived at Osu's house before joining the organization when Osu founded Fake KNIFE. He is a young man with white hair and a kind impression, with wings attached to his waist. However, he does not have the ability to fly. He usually runs a flower shop in Naga's neighborhood, so even before their connection through SPOON and KNIFE, they knew each other as the 'neighborhood flower shop hyung' and a 'friendly high school student.' He is Iho's twin brother. Normally, their impressions and hairstyles are completely different, but when he grins, they look identical. Ilho is his real name, not a codename.

A member of Fake KNIFE, where Osu is the boss. He is Ilho's twin brother and Eunbidan's older brother; his real name is Iho, not a codename. Like Ilho, he has white hair and wings on his back, but unlike Ilho, his white lab coat and expressions give off a strong 'mad scientist' vibe. In contrast to his simple-looking older brother, he has the impression of a mischievous rascal. Based on various hints, he seems to have lived for at least several centuries. Although he appears to be an unemployed slacker, he holds the highest level of education in the series. Even in the story, Ilho openly criticizes him for just sitting around being useless. Furthermore, he is very dedicated to his hobbies, such as collecting internal organs.