Hatabō debuted in the Osomatsu-kun manga, created by Kenichiro Takai at Fujio Akatsuka's request to expand the cast. His name, meaning "flag boy," was chosen via a Shonen Sunday reader contest. Initially portrayed as a young child, often much younger than the Matsuno sextuplets, his depicted age varied inconsistently across stories, sometimes placing him in their grade or older. His defining feature is a small Hinomaru flag protruding from his skull; this flag transforms for narrative needs, becoming a US flag in American settings, a skull-and-crossbones for the assassin persona Joe Hatabō, or a solid red flag for the Communist Party of Japan in the "Hatabō and Wanpei" stories. Other design elements include a shaggy Kappa-like bowlcut, a single bucktooth, vertical lines under his nose suggesting a runny nose, and whisker-like cheek marks implying dried mucus. His attire varied, from a one-buttoned shirt and pants matching other Akatsuka child characters to green overalls with a baby chick print in the 1988 anime. As a child, Hatabō acted with simple-minded freedom, often at his own pace and with limited intelligence, making him susceptible to bullying by the sextuplets and Chibita. Yet he occasionally displayed unexpected physical strength, overpowering Chibita, and could exhibit cunning and command when antagonistic. His intelligence fluctuated across adaptations; the Shonen King run and 1988 anime portrayed him smarter, though Fujio Pro consistently categorized him as a "baka" (fool)-type, emphasizing vague liveliness and lack of deep thought. His speech included the tic "da jo" or "jo," with early 1988 anime episodes limiting his dialogue to self-introductions like "Hatabō da jo!" As an adult in Osomatsu-san, Hatabō remains physically small and childlike, appearing unchanged from his teens despite being the sextuplets' age. He wears green overalls over a light yellow hoodie. Initially prominent as wealthy "Mr. Flag," his naivety and inability to manage finances or business led employees to abandon him and his fortune to collapse. This arc tempered his earlier, more severe traits, solidifying his default characterization as an innocent, kind-hearted man with persistent childish habits like riding a tricycle and seeking companionship. His relationships remain dynamic: sometimes a follower or friend to Chibita, occasionally antagonized by him or targeted by Iyami, and sporadically depicted as Dekapan's son or mentee. Alternate universes depicted Hatabō differently, like a beer ad envisioning him as a wealthy comedic actor with a nose hair mustache in adulthood. Foreign adaptations replaced his name with culturally specific terms, like Cantonese "Sek Baan Jyu" (Grouper fish) or crude Spanish/Galician slang referencing genitalia. His evolution across media reflects a shift from a variable supporting role in Osomatsu-kun to a more defined, whimsical presence in Osomatsu-san, maintaining core traits of simplicity and the flag motif while adapting to adult narratives.