Saheiji is the foster father of Joe and Yukimura and leader of a pack of sixty dogs in Nagano prefecture. He takes the two from Sakura because she was too ill to care for all her three sons. Foster father and children are attacked by a group of macaques, Joe is thought dead and dragged away by the monkeys while Saheiji becomes paralyzed on his back legs after being hit on his back to protect Yukimura. After the attack, Yukimura's personality changed and Saheiji tried to talk some senses into him but without results. Yukimura became leader of the back but he still considered his foster father as true leader.

He meets Weed and the Ohu soldiers after that Yukimura rescued them from the monkeys. He tried to talk again with his foster son, since he was torturing a baby monkey and treating badly the guests but, again, with no results. He wasn't even able to tell Yukimura about his real father, because the young dog didn't want to listen, saying that Saheiji was the best father of all. When he tells Yukimura to help Weed's pack against Shogun, he goes and, shortly after, Saheiji meets Gin and other Ohu dogs, telling them about Sakura, Yukimura and Weed. Carried by Hiro to the battleground, he arrives too late and sees his son Yukimura dying. He tells Yukimura that he and Weed are brothers and that Gin is his real father. Yukimura dies, leaving Saheiji depressed, loosing his zest for life.