Purple Haze Feedback is a spinoff novel written by Kadono Kouhei and co-authored by Hirohiko Araki who drew the insert art and offered story guidance. This review will contain spoilers for the manga "Jojo's Bizarre Adventure: Vento Aureo," so read that before reading this review. There will be no spoilers for Purple Haze Feedback, except for the events set up in chapter 1.
Purple Haze Feedback takes place about a year or so after the events of Vento Aureo. Giorno Giovanna is the new boss of Passione, but not everything has changed since he ousted Diavolo. A narcotics group is still running wild in Passione, but
they cannot be stopped by Giorno himself. To defeat them, Giorno sends his subordinates Guido Mista and Sheila E. to recruit a friend of his who abandoned him and his group during the events of Vento Aureo. This person is Fugo Pannacotta, the user of the Purple Haze stand.
By far the most interesting aspect of Purple Haze Feedback is how it delves into Fugo's psyche. His extreme anger is alluded to in Vento Aureo by the appearance and abilities of his Stand, but nothing ever really came of it. Here, the reader is able to get right into Fugo's head and truly understand his motivation both during Vento Aureo and with his new mission given to him Giorno. The way he's fleshed out is both consistent with his actions in Vento Aureo, and also very compelling from a narrative standpoint. You slowly start to see Fugo's attitude change, and it happens in a very natural and believable way.
The new characters created for Purple Haze Feedback are also very interesting and unique. Fugo is joined by two companions to take down the narcotics gang, and the narcotics gang itself is made up of four members, all very distinct and memorable. Although Fugo gets the most attention, the side characters certainly add a lot to the story and don't feel as if they were written to be defeated or add another fighter to the mix. Aside from Fugo, most of the scenes with Vento Aureo characters are flashbacks shown from Fugo's point of view, and some of these scenes were already in Vento Aureo to begin with. However, they all benefit from knowing what Fugo was thinking at the time, and as such are a necessary addition.
Another aspect of Purple Haze Feedback that bears mentioning is the exquisite attention to detail. Kadono Kouhei demonstrates his knowledge of Italian culture and Jojo itself with very clever references and allusions that will leave fans very pleased. His treatment of the pre-existing characters is very much in line with Hirohiko Araki's, and as such it feels like a proper continuation rather than an inconsequential fluff piece. The new stands themselves feel a bit grounded compared to some of the insane ones in Vento Aureo, but they're all different and unique enough to not feel as if they were already done in Jojo before.
There isn't many negative things I have to say about Purple Haze Feedback. It should be obvious, but the book does not work as a standalone piece. Various plot elements will only be understood by readers who have already read the Jojo manga, and several concepts are simply unexplained since it's assumed the reader is already familiar with them, such as stands. The ending is also a bit rushed, but it suitably wraps up the story in a satisfying way.
Overall, Purple Haze Feedback is a must read for anyone who read Vento Aureo. It fleshes out a character who was in dire need of fleshing out, and also adds interesting details to both Vento Aureo and Jojo as a whole. This review was purposely kept as spoiler free as possible so that anyone who hasn't read the book will give it a shot. It's debatable if it can be considered canon, but seeing as it doesn't contradict anything in Vento Aureo or future Jojo parts, I feel it's safe to say it is. It's a short read, so give it a chance.