Seijuro Uehara

Chapter 6 "Private" features the name and appearance of a deceased person. Taiki Himekawa's (legal) father. He was an unsuccessful actor who sought relationships with talented female entertainers to distract from his own feelings of inferiority. Before Ai moved to her new residence, when Himekawa was 5 years old, he and his wife, Himekawa Airi, who was also Himekawa's biological mother, are said to have committed suicide together.

Aquamarine, based on the results of a DNA test with Himekawa, erroneously concluded that Seijuro, though not their mother, was the biological father of the Hoshino siblings and the mastermind behind Ai's murder, leading her to temporarily cease her revenge believing her target was already dead. At this time, the stars in Aquamarine's eyes disappeared, and her personality became as calm as another person's. Aquamarine tried to live her own life, not obsessed with revenge, but in reality, Seijuro had already died by the time Ai moved, making it impossible for Seijuro to have provided Ryosuke with the relocation information. Thus, Akane Kurokawa and others realized there were inconsistencies in Aquamarine's reasoning.