岩城 昭夫

One of the participants of the rite. He is a high-ranking member of his corporation who finds his duties boringly easy. He isn't interested in winning the rite but spends his time trying to find the location of the Mikado clan's secret treasure.

An impostor whose real name is Kawamura Shinya (川邑 信也), a private investigator who was best friends with the now-deceased Mikado Kouji. He infiltrates the mansion in disguise in hopes of exposing the truth behind his friend's death (the disguise is so good it fools Aya whom he spent time with when she was younger). He confronts Heizou with evidence proving his friend's cuckolding and is forced to leave the mansion before the rite is complete to avoid being killed by the Mikado household.