Koichi Akiba

Koichi Akiba was a human who plotted with the rest of his family to kill his grandfather so he could inherit his fortune. He was the daughter of Shuji and Miharu, the grandson of Shuzo, and the brother of Asami.

History
Koichi owns a theatrical company that has been described as destitute and always short of money. This coupled with fancy tastes meant he had high debts.

Desperate for money, he concocted a plan with his mother to kill his grandfather to inherit his part of the fortune, talking his sister Asami into helping. The plan involved using stage lighting and sound effects from his company. When Asami drove him home from the hospital she would drive quickly to scare him and then the stage lighting would come on, fooling his frandfather into thinking they were about to collide with a massive truck and scaring him to death.

A Soul Lost in Darkness
The plan to kill his grandfather has gone off without a hitch. On their way back with his grandfather's body in the back of Asami's car, he decides he's hungry so he, his mother, and sister stop at a restaurant for a celebratory dinner. When Asami asks what they should do with Shuzo, Koichi tells her to just leave him in the backseat. Anyone who sees him will just assume its an old man taking a nap.