Naruse Masato

Actually, he was abused by his father, and his mother closed her eyes to his abuse. Being so lonely, he "created" his illusion of a brother, the only person with whom he could actually talk. They drew a story about a wolf and a rabbit, where the wolf eats the rabbit and dies because he has eaten unpure flesh. There Masato was rabbit and wolf—his dad. It could be said that it has become a rule. Then the protagonist was bitten by a dog and told his brother about it. His brother (taking control of his body) killed many dogs.

Masato thought that his mother was looking for him, that she was on his side, but one day everything changed. They fought over something trivial, and then the mother blamed him for the family problems. He concluded then that she was like his father and started killing girls who looked like his mother. After that, the mother tried to kill them and slit her wrist once more. She was alive and would live through, as she did many times, since she did not actually intend to die, yet her brother found her and carried out the sentence.

He, or rather "his brother", is the so-feared Jack the Ripper.