He is also the oyabun (親分), or "boss," of the local yakuza organization. He is not named in any of the released media.
Due to her marriage to an outsider, Akane was dismissed as her mother Oryō's heir in favor of her oldest daughter, Mion. The manga contains more detail in that Akane defeated her mother in a kendō match. Oryō did reconcile with her daughter and her husband but all sort of accept she has to publicly maintain her disappointment.
In the episode Confrontation of Minagoroshi-hen he obliquely confesses his organization's responsibility for Satoko's situation. As hinted in previous arcs, Mamiya Rina steals money from the yakuza who make a gruesome example of her. This causes her lover/pimp Hōjō Teppei to flee Okinomiya to return to Hinamizawa where he renews his custody and abuse of Satoko.