Yūjirō Bizen's Big Sister
She originally lived in Akita Prefecture but she moved to Miyagi Prefecture after she got married. She now lives there alone. Her husband died few years ago and she has no children. She decided to have a dog to give her company and got Yamabuki.
Unfortunately, she was getting ill from age. She had to go to the hospital and gave her dear Yamabuki to her younger brother to take care of. Unknown to her, Yamabuki had 5 puppies while away.
Many months later, she starts to get better and is allowed to move back home. She calls her brother, wishing to have Yamabuki back. Yūjirō drives to see her with his family and return her pet dog. She cries from happiness after seeing Yamabuki again. His brother also brought Yamabuki's son Riki. She is at first confused but finds Riki a lovable puppy.
She is still weak but refuses to go to the hospital as she wishes to die in her own home instead. She keeps Yamabuki but is unable to keep Riki due to her state. His brother and his wife are worried about her but she assures that everything is fine since she has a housemaid to help her.
Yūjirō's Big Sister isn't seen nor mentioned after this, but it's known that Riki kept visiting her house to see his mother Yamabuki.