Kaoruko Tachibana (橘 薫子 Tachibana Kaoruko): Sakon s aunt from his mother's side and assistant police detective. She often follows Sakon on his journeys so she can meet handsome men and eat delicious food, and believes herself to be a rare beauty. She also often focuses more on the motives of people involved in a crime rather than their alibis and possible method of murder, which she often relies on Sakon for. She insists that Sakon call her "Kaoruko nee-san" rather than "Kaoruko obaa-san" and hits Ukon whenever he insults her or says a careless remark.