Hyōgo Otoo established and manages the Wagnaria family restaurant chain, yet rarely sets foot inside due to his relentless quest to find his missing wife, Haruna Otoo. Haruna vanished after becoming hopelessly lost during a simple milk run, her notoriously poor sense of direction leading her on an unintended odyssey across Japan, traversing sewers and forests. Otoo occasionally resurfaces at Wagnaria to oversee operations, bearing peculiar regional souvenirs or snacks primarily meant for the manager, Kyōko Shirafuji. These offerings invariably provoke the head waitress, Yachiyo Todoroki, who interprets them as romantic advances and threatens him with her katana. His presence is so insubstantial that Souta Takanashi once identified him as mere "air" to prevent Mahiru Inami's fearful attack. While searching for Haruna, Otoo discovered Aoi Yamada, a runaway teenager falsely claiming her parents perished in a fire. He brought her to Wagnaria, where she started working and residing in the attic. Yamada formed a deep attachment to Otoo, idealizing him as a father figure and persistently petitioning him for adoption. He responded to her demands with unwavering patience and kindness, though he consistently refused. Otoo later expressed profound gratitude for Yamada's unique knack for locating Haruna during her disappearances. His years-long dedication to finding Haruna involved collecting objects resembling her during his travels. His efforts culminated in a reunion facilitated by Yamada and Kikuno Yamada (Aoi's mother), who escorted Haruna back to Wagnaria in Season 3, Episode 7. This reunion proved fleeting due to Haruna's persistent navigational struggles. Otoo recruited several staff members, including Yamada, and maintains a gentle demeanor even when facing Todoroki's threats or Yamada's familial pleas. Employees like Popura Taneshima regard him as a caring figure despite his scarce appearances.