This is basically the jotakak version of a yandere Jotaro x Reader. Yes the child is Jouta.

Kakyoin finally left Jotaro. After he found out about the egg he just layed in his sleep, he took the opportunity to leave Jotaro since he was asleep. Kakyoin drove far away from the house. He drove to a place called Morioh. Once he got a house and moved in, he didn't know what to do with the egg. Kakyoin walked into the room holding the egg. "Now what to do with you," Kakyoin said to himself. Then the egg started hatching. Kakyoin was shocked and confused. 'What should I do?' Kakyoin thought. Then the egg cracked, there was a baby inside it. It had Jotaro's hair but with with Kakyoin's eyes. Kakyoin slowly walked towards it and gently picked up the child. He noticed it had the Joestar birth mark. 'It's me and Jotaro's child...' Kakyoin thought, 'What should I name him?' "J-Jouta?" Kakyoin stuttered out loud. "Yeah, Jouta," "I like the name but I don't like who it reminds me of..." "He'll never find me anyways." Kakyoin got a soft blanket and wrapped Jouta in it. "We'll live a good life together." Kakyoin said.

Three years later...

Aka the part where they find out about Kira in part 4...

Also Jouta has his stand...

Kakyoin's outfit!

Kakyoin walked down the sidewalk with Jouta holding his hand. Him and Jouta were talking. "Can we go to the beach?" Jouta asked. "Sure," Kakyoin replied. The two walked to the beach. Jouta played in the sand while Kakyoin was drawing in his sketch book. "Kakyoin..." A familiar voice said. Kakyoin turned around. "Jo-Jotaro..." Kakyoin said. Kakyoin brought out his stand, Hierophant Green. Jotaro brought out his, Star Platinum. "What do you want from me?"  Kakyoin asked. "Why did you leave me?" Jotaro asked. Kakyoin didn't respond. "Daddy, who is he?" Jouta said, "He has a stand like us." Jouta brought out Charmy Green. "Why does his stand look similar to mine?" Jotaro asked angrily. "Because, because..." Kakyoin muttered. "Because what!?" Jotaro asked. Then grabbed Kakyoin by the collar. "Leave my daddy alone!" Jouta said. "He's your son..." Kakyoin said. "Jouta he's your father." Jotaro let go of Kakyoin and apologized. "Your stand does look similar to mine." Jouta said. Hierophant Green held Charmy Green. Star then hugged Hierophant. "At least you're safe." Jotaro said. "What do you mean?" Kakyoin asked. "There's a murder on the lose," Jotaro said, "and since you and our son are here." "I'll do anything to protect you, my cherry and my son." Jouta was confused but thought that his other father wants to protect him and his dad. "We'll be safe with my other dad!" Jouta said. "Yes, you and you father will be safe with me."Jotaro said. Kakyoin couldn't do anything. He was now stuck with a man that has a powerful stand and who is obsessed with him. He couldn't leave him mainly because of Jouta and a murder on the lose isn't helping the situation either.

Fin...