WARNING: The following contains major spoilers for Boruto: Naruto Next Generations Chapter #51, by Masashi Kishimoto, Mikio Ikemoto and Ukyo Kodachi, available now in English from Viz Media.
The latest chapter in the Boruto manga is certainly an ominous one, as it seems like Naruto will have to sacrifice himself to save Boruto, Sasuke and the free ninja world from Isshiki Ōtsutsuki. The alien's unleashed his full form and unfortunately, Konoha's shinobi can't stop him, leading to Isshiki breaking Boruto's hand and knocking Sasuke near-unconscious.
Naruto, however, has an ace-in-the-hole, seemingly tapping into Kurama's power to create a new Sage Mode, one that will destroy his body and most likely leave him a martyr. However, there's one secret move Sasuke has that could let him resurrect Naruto by sacrificing his own life.
This is the Samsara of Heavenly Life Technique, a forbidden move users access through the power of the Outer Path. It's available to those with the Rinnegan eyes, which Sasuke gained after the last ninja war and Itachi's death. He and Naruto were powered up by the Sage of the Six Paths to fight off Kaguya, and while Sasuke prefers not to cross the barrier between life and death, this could be the exception.
Nagato used it when Pain and the Akatsuki destroyed Konoha, right after Naruto taught him what peace and love meant. However, this move uses up so much chakra that it kills the user. Now, one would think Sasuke might consider Naruto's death here natural, but in terms of diplomacy, Naruto as Hokage is very important to the future. Sasuke's a great Ranger but ultimately, he's a soldier and him wanting Naruto to continue building bridges and a utopia will bring his redemption full-circle.
It fits the narrative because these sacrifices are what Shisui and Itachi made to make a better world, so Sasuke would fall in line with them and once more prove the Uchiha clan did have heroes. His death would also beef up Boruto's arc as Sasuke is his main mentor, plus it would continue to inspire Sarada to be a better Uchiha warrior and continue clearing her clan's name after years of bloodshed.
Knowing her dad brought Naruto back means Sarada will want to honor the legacy of the Hokage office and what Sasuke died for -- it might even make her stronger, as strife is the main way Sharingan users get more Tomoe. Sasuke resurrecting a Hokage sets the stage perfectly for this, which would also accomplish what Madara once wanted. An Uchiha leader like her, with a firm understanding of love, family and loss, is the ultimate redemption story, motivating the Uchihas of tomorrow to aspire higher.
This would also connect Sarada to Naruto's family even more, pushing the Boruto-Sarada ship closer to setting sail. Conversely, the grief will add more depth to the series because it'll remind Konoha that peace may be an illusion for the next generation. At the end of the day, it's been a long time since the Uchiha garnered any respect, so Sasuke's heroic move could change that dynamic forever, bookending his journey after he came back to the light and Naruto's side.
