Chapter 7

The Vow to the Father is the seventh chapter of the JoJo's Bizarre Adventure manga. It is also the seventh chapter of Part I: Phantom Blood.

Summary
Seven years back, Dio is trying to give his father some medicine only to be hit by Dario who would rather drink booze than take medicine. Dario also wanted Dio to sell his mother's dress saying he doesn't need some "dead bitch's stuff". This causes Dio to cry and finalize his decision to kill his father. Later, Dio, wearing a mask, goes to a Chinatown area to get some Oriental poison from a man named Wangchan.

Back in the present, Jonathan learns that Dio killed his dad and is trying to use the same poison to kill George. Dio denies this claim but Jonathan says that he plans to investigate the medicine to see if it's legit. Dio tries to make Jonathan return the medicine to the tray, but he refuses. However, Jonathan says that if Dio swears his innocence on his father's honor, he will return the medicine and never speak of it again. However, Dio refuses and says that someone like Dario had no honor at all. The thought of Dario causes Dio to hit Jonathan. However, the years have past and Jonathan is much stronger now. Jonathan grabs hold of Dio and throws him down from the second story of the house to the first. Jonathan knows that they never were friends and says he'll make sure to get the medicine analyzed and send Dio to jail. Dio knows it will take Jonathan at least three days to find proof of the poison and says that he'll have to finish off Jonathan before then.