Boruto: Naruto Next Generations may have started the Mitsuki Disappearance arc with a greater focus on Mitsuki's inner turmoils, but as it has progressed it's clear that the focus have shifted more toward the former Tsuchikage, Onoki.
With the finale of this arc fast approaching, it may very well come full circle as the synopsis for a future episode teases that Onoki may have to sacrifice his life as a way to avoid the death of others.
Translated by @OrganicDinosaur on Twiter, Episode 91 of the series is titled "Ohnoki's Will," reads as such, "Kuu apears once again in front of Boruto and his comrades. No matter what happened, Boruto tries to belive in Mitsuki. Kuu sneers at him for it, trying to provoke him. He tries to start attacking Boruto, but someone is preventing him from doing so. at that time, Onoki uses the assitance of Sekki, a Hidden Stone shinobi."
Going further the synopsis reads, "One way or another, they struggle and manage to reach Kuu's location. Onoki is introspective once again, and reconsiders what his own true will is. In order to stop Kuu from rampaging any longer, he resigns himself to a battle to the death."
Onoki originally began the plan to create artificial beings after the death of his grandson Kozuchi as a way to avoid the deaths of other humans. He's been wanting to keep the bloodshed to a minimum, but the plan started blowing up in his face as the Fabrications began developing their own emotions and desires.
So it seems like as the Mitsuki Disappearance arc comes to a close, Onoki is going to come face-to-face with the human sacrifice that he's been dreading. It would be a fitting way for the arc to come to a close for Ohnoki to finally accept the importance of will for both the humans and his Fabrications.
If he does sacrifice himself, then it would be fully accepting what he set out to do and sacrificing his own life to avoid the loss of another. It would also add a semblance of importance to this arc, as the series has very few deaths overall.
Originally created by Masashi Kishimoto, Naruto ran in Shueisha's Weekly Shonen Jump for 700 chapters. The story follows a young ninja, with a sealed demon within him, that wishes to become the leader of his home village. The sequel, Boruto: Naruto Next Generations is set several years after the events of the original Naruto story and features the children of many of its key characters such as Naruto and Hinata.