Dayon originated as a versatile background character in the earlier *Osomatsu-kun* manga and anime, created by Fujio Akatsuka's assistant Kenichiro Takai to expand the series' cast. His distinctive design, featuring a notably large mouth stretching his face and prominent stubble, was reportedly inspired by Kiyoichi Tsunoda pressing his face against glass as a prank. This exaggerated mouth facilitates visual gags centered on his gluttony, enabling him to swallow objects or people whole. His personality remains broadly simple and easy-going across appearances, though his specific roles vary significantly between *Osomatsu-kun* and its successor *Osomatsu-san*. In the original series, he frequently appeared in minor occupations like police officers or shopkeepers. Contrasting with his later *Osomatsu-san* portrayal and appearances in related media like the film *Hipipo-Zoku to Kagayaku Kajitsu*, he adopts a more enigmatic presence, often functioning as a cryptic figure who appears unexpectedly to perform strange or inexplicable actions. His speech patterns consistently end with his name-derived verbal tic, "dayōn" or simply "yon". In *Hipipo-Zoku to Kagayaku Kajitsu*, Dayon appears as a supporting character within the ensemble cast. His role aligns with his established *Osomatsu-san* portrayal as an ambiguous figure contributing to the film's comedic chaos, without new character development or background expansion. His physical design remains consistent, typically featuring a khaki suit, slicked hair, and his signature facial features. Available sources do not detail his relationships or broader history.