Kamon

Kamon also known as Kuchinawa is a former senior disciple from 900 years ago. Following the Great Kanto Earthquake he was serving Tanehiko who captured and murdered women in his mansion by getting rid of their corpses. Just as he reunites with Mao who came to rescue Tanehikos last victim Tenko he was hired by his father to kill him as he was removed from power of the mansion due to his murders and does so by making his heart squeeze out. He and Mao then recognize each other and have a conversation about what happened 900 years ago although Kamon didnt know much detail.