Diamond is Unbreakable - Chapter 16 
The Nijimura Brothers, Part 8 (虹村兄弟 その⑧ Nijimura Kyōdai Sono 8), originally The Strange Man in the Attic (屋根裏の怪人 Yaneura no Kaijin) in the WSJ release, is the sixteenth chapter of Diamond is Unbreakable and the two hundred eighty-first chapter of the JoJo's Bizarre Adventure manga.
Koichi tells Josuke that they must find the Bow and Arrow so that no one else will die from being pierced by it. Josuke tells Koichi that it may be upstairs. They both go upstairs, where they hear a chain dragging on the floor. Koichi is afraid to go inside, but kicks open the door, only to be grabbed by a monstrous creature. Josuke punches the creature, cutting off his hand. The creature regenerates the hand quickly.
Keicho enters the room and tells them that this monster is unfit for the light of day and that he is actually the Nijimura's Father. Keicho says that this Bow and Arrow are his most precious possessions because he is looking for a Stand user to save his father. Josuke asks if they want to heal his father, but Keicho replies that he wants to kill his father. 10 years ago, Keicho's father was implanted with DIO's cells and transformed into this creature when DIO died. Keicho tried to kill him many times but he always regenerates. He wants to end his father's misery.