Spoilers ahead for Boruto chapter 72!
In classic Otsutsuki fashion, after his seeming selfless sacrifice to save Boruto from Kawaki's death blow, Momoshiki's sudden reappearance reveals that he never intended to give up the possibility of returning. This is in line with the hardwired philosophy of all Otsutsuki, including Isshiki, to never die without an effective backup survival plan.
In accordance Like Momoshiki and Boruto, nearly all of Isshiki's "data" was ed into Kawaki before he was stopped during the final transfer of data.
In Boruto chapter 72, readers learn that Momoshiki did not die after all, as he appears to Boruto just before Naruto's son is about to go on an important mission to save Konoha Village. It appears that, before sacrificing himself, Momoshiki implanted a bit of himself into Boruto's consciousness such that they can communicate with one another. The idea seems similar to the way Naruto communicated with the Nine-Tailed Beast sealed within him. That is, while Boruto may still be Boruto, he will be riding with Momoshiki, who will occasionally provide internal commentary, advice, and criticism whether he wants it or not.
Momoshiki's presence in Boruto's mind suggests that same should be occurring with Isshiki and Kawaki. Isshiki was the Otsutsuki originally tapped centuries ago to mine the Earth for the God Tree. He was thwarted when his partner Kaguya decided to take the Earth for herself. He survived only because before he died, he engraved his Kama on a monk ing by his body. His Kama was inscribed on Kawaki, because after experimenting with others, he presented the best fit for Isshiki to live a long and prosperous life. While Isshiki was defeated, it is unlikely that he, a more senior member of the Otsutsuki Clan, would not know about dropping a bit of himself into Kawaki's conference as a fail-safe.
Considering the bottomless desire of the Otsutsuki Clan to live, it seems unlikely that Momoshiki would have thought about implanting himself in the consciousness of a vessel but Isshiki would not have thought of the same fail-safe. More specifically, the return of Momshiki paves the way for the return of Isshiki, most likely in a similar "ghost whisperer" form to Kawaki. What's even more interesting is that if Isshiki does return, what will his relationship with Momoshiki be? Only time will tell in future chapters of Boruto if Issihiki has a similar relationship with Kawaki as Momoshiki has with Naruto's son.
Boruto is now available from Viz Media.
