Jujutsu Kaisen Modulo is a spin-off series by Gege Akutami that has been the talk of the town recently, and for good reason. It seems the creator has taken fan criticism of the original series and worked on his world-building. The style of revealing the lore has also changed. Recently, Modulo released another promotional video, and a particular detail has caught the attention of fans.
Yuji Itadori’s voice actor, Junya Enoki, is unmistakably the one guiding the promo, and that single choice has sent shockwaves through the Jujutsu Kaisen community. This has led fans to ask one question: If Itadori is the narrator in Jujutsu Kaisen Modulo, would he be something like how Tengen was as an omnipresent narrator in the original series?

Because if this ends up becoming true, then Jujutsu Kaisen Modulo would not just be a simple spin-off series, because there would be added depth that would make it a complete narrative evolution. In the original series, Tengen was the one who narrated the story, and his character was perfect for this because of his detachment from humanity. He was someone who existed beyond the concept of time, and now that we know that Yuji is someone who also does not age anymore, it could be plausible that he has taken over this role.
Although Yuji Itadori, on the other hand, is the exact opposite. He is emotional, burdened by guilt, deeply human, and if the promo is any indication, stripped of the youthful optimism that once defined him. This sounds like someone who has lived far too long, seen far too many funerals, and carries the weight of a century of loss.
How Jujutsu Kaisen Modulo’s lore supports the narrator theory

Yuji, being the narrator for Jujutsu Kaisen Modulo, has opened up interpretations that end up aligning with the lore we know behind him. There was one event that changed the way he looked at life, and that could have been the cause of him losing the last shred of his humanity and his goofball energy.
It was when he attended Hana Kurusu’s funeral, admitting he can no longer watch any other friend of his die while he gets to live on. This character has now visibly gone through various changes, and he is not the boy we knew. The situation around him has pushed him to mature and stay detached from the world. Now it makes sense as to why his character would be especially chosen to become the narrator in Jujutsu Kaisen Modulo.
Yuji becoming the observer instead of the protagonist

Now that the story is focused on Tsurugi, Yuka, and the next generation of Jujutsu sorcerers, where even the threat they are facing is not something that the original cast could have even imagined, facing it would be in the best interest of Yuji to be the observer rather than the protagonist. Moreover, his story is over, and it would be graceful for him to only intervene if it was absolutely needed and let nature take its course, and allow the future generation to beat the Simurians. Fans have had a positive reaction to this addition and are still rooting for the creator could still end up making him an important part of Jujutsu Kaisen Modulo, especially when the final battle has already begun.
Final thoughts
Gege Akutami is known to make moves in ways that would confuse fans. That does not mean that having Yuji's voice actor narrate in the promotion video could be just a coincidence. It could very well be a calculated choice, as fans have been impatiently waiting for him to make a proper entrance in Jujutsu Kaisen Modulo. So if he is the narrator, it would mean that while he is off-screen, he has an active part in the series.