Yohei Umino is the adoptive father of Nagi Umino and biological father of Erika Amano and Sachi Umino. Married to Namie Umino, they co-own and operate the family restaurant "Umino Tei". He appears young for his age, sporting blond hair with shaven sides. Yohei is frequently seen wearing sunglasses, a red button-up shirt, ash-gray pants, a black leather belt, and black shoes. Kindness defines Yohei, especially with his children, though he possesses a volatile temper that surfaces more readily than Namie's during stress, like family conflicts. This temperament stems from his high school days as a former delinquent, a past shared with Namie. During their school years, he courted Namie with persistent love letters, which she kept despite later embarrassment. Support and sacrifice mark his family role. He and Namie seriously considered selling their restaurant to fund Sachi's private high school education. He maintains a supportive paternal bond with Nagi, reinforcing Nagi's place in the family after the birth switch discovery. Fishing is his chosen leisure activity, offering him an escape where he can "forget all your troubles". Within the household, Namie holds primary authority, with rules reflecting her leadership. Yohei's dynamic with his wife includes playful arguments, a continuation of their long partnership from delinquent youths to restaurant partners and parents.