Diamond is Unbreakable - Chapter 8 
Jotaro realizes that Anjuro wasn't born a Stand user, but became one. Anjuro confesses the man who made him a Stand user wore a Japanese school uniform. Last year, Anjuro had trouble sleeping before his death sentence. Someone came into his cell wearing a school uniform but did not reveal his face. As Anjuro demanded what was happening, the man shot him with the Bow and Arrow. As Anjuro survived, the man gave him a "gift", called a Stand. When he was hung the next day, Anjuro didn't die, that was when Aqua Necklace came to be and the criminal escaped. The man did not reveal his name right away to Anjuro but told him to meet in Morioh if he wished to know more about him. With that, Jotaro began to realize that the man with the Bow and Arrow is the new enemy.
Before they can do anything further, a child is heard screaming. Aqua Necklace is still active and is trying to strangle the child. Anjuro then demands Josuke to change him back to normal or his Stand will murder the boy. As Josuke calmly considers complying, Anjuro makes an inappropriate comment about his hair. Angered, Josuke has Crazy Diamond beat Anjuro, infusing him further and creating a rock face. Aqua Necklace is no more and Jotaro remarks about Josuke's deadly personality.