Board Thread:Episode Discussions/@comment-35594580-20181118172605/@comment-25122992-20181118174152

Actually, it wasn't Kozuchi. Kozuchi was said to be Oonoki's grandson, while the masked Ku reffered to Oonoki as his father. So, it's clear that Ku is Oonoki's son and obviously the father of Kozuchi. And we can also assume that both Ku and Oonoki came to these malicious plans for some reason connected to Kozuchi's forementioned death.