Keiji Asou

In reality Asou and his family were trapped inside their house by a drug ring because he refused to associate. The ring then set the house on fire in order to silence them and made it look like a murder-suicide. The truth behind the incident wouldn't come to light till 12 years later during the events of Moonlight Sonata Murder Case. Asou's son, Seiji was the only survivor because he was hospitalized in Tokyo for chronical illness, but people believed he was a different person not tied to the family. After learning the truth, Seiji changed his name to Narumi Asai, dsiguised himsef as a female doctor and returned to Tsukikage Island to execute a series of revenge murders matching the movements of the Moonlight Sonata.