Spoilers for Crazy Diamond's Demonic Heartbreak Ch.10The villainous DIO is one of the most iconic enemies in Jojo's Bizarre Adventure, while Josuke Higashikata is one of the series' most popular heroes, so it's a shame that the two never got the chance to go head-to-head... until now.
The spinoff series known as Crazy Diamond's Demonic Heartbreak follows Josuke as he aids the reformed minion of DIO Hol Horse in retrieving a Stand-wielding parrot that once belonged to the vampire himself. This parrot has a Stand ability like Pet Shop did, and it's pretty dangerous, as it is able to force its victims to relieve any memory it witnessed--from warlord atrocities down to the events of DIO's final battle with Jotaro and the other Stardust Crusaders. Hol Horse was seemingly forced to kill the parrot, but its sudden reappearance left Josuke under the effect of its powerful Stand.
In chapter 10, the parrot known as Petsounds decides to subject Josuke (and Boingo, a.k.a. Mondatta in Jojo's English translation) to a very particular memory: the memory of the death of its trainer. Petsounds and Pet Shop were both trained to use their Stands by a talented falconer, but this falconer didn't become one of DIO's minions. Instead, DIO killed him without mercy, and Petsounds is forcing Josuke to relive the event from the perspective of its former master. Josuke finds himself seemingly in Egypt, and freezes as he hears DIO's voice, feeling every bit of fear that the falconer did. The falconer, caught by DIO after attempting to flee, is then attacked by the very birds he trained--an attack to which Josuke is about to be subjected to. Josuke attempts to block Pet Shop's attack with his own Stand, but that's not how the memory goes. Powerless to stop the onslaught, Josuke is struck by a spear of ice as the chapter ends.
Josuke Versus DIO is a Fan Dream Turned Nightmare
Fans of a franchise with many parts, like Jojo's Bizarre Adventure, will naturally wonder how the hero of one part might stack up against the villain of another, so getting to watch Josuke face-to-face with DIO should be the ultimate fan service. However, the context of the fight and the fact that DIO is merely an illusion definitely changes that. It's literally impossible for Josuke to fight at all, much less at full strength, and this illusory DIO can't respond to his actions anyway. Since Crazy Diamond's Demonic Heartbreak is a prequel, Josuke barely knows anything about Stands at this point and likely wouldn't fare well against the real DIO, so it's probably for the best. At the very least, Josuke ought to have a new appreciation for what Jotaro has already dealt with, and it might explain why he was able to trust Jotaro relatively easily.
Crazy Diamond's Demonic Heartbreak has been bringing together different eras of Jojo's Bizarre Adventure, and Josuke seeing DIO in all his power is only the latest instance of that. The spinoff has been built especially for the most dedicated fans, drawing connections between characters and plot points that previously had no relation. Fear, and fear of DIO in particular, has been a major theme, so with any luck, this turn of events will help Josuke and Hol Horse understand each other better and let them work together to ensure no one else must suffer because of this bird again in Jojo's Bizarre Adventure.