After the war Sasuke got back on good terms with the leaf and set out on a journey.[1] Sasuke went on this journey for two reasons, one of which was for his atonement.[2]
Sasuke did a lot of foul things as a kid, granted he was much younger, less wiser and ultimately misguided. Still, he inflicted some serious damage and caused plenty of pain to the shinobi world. So he decided to travel the world to places where his hands or his name created conflict, offering help to correct the mistakes he made in the past.[3]
Sasuke couldn’t afford to make another mistake. Even though his darkness was defeated, Sasuke(and Naruto) failed to get rid of it. Sasuke still has darkness brewing deep inside him,[4]
‘A violent impulse that ate into reason slept within his body.’ Back during the start of the 4th war, Kurama knew Sasuke' darkness couldn’t be erased,[5] and that still holds true in his adulthood. As for now Sasuke feels he has things under control. Still, Sasuke also knows that getting consumed by darkness again and reverting back to his former self can happen at anytime, all it would take is a moment of weakness[6] and confusion.[7] Making more bonds increases his chances of falling into darkness, so journeying is something Sasuke must do alone. This allows him to learn about his momentarily suppressed violent nature, so he can control it.[8] Which leads us to the other reason for Sauske' journey.
The second reason for Sasuke' journey was his desire for information. He wanted to know more about the shinobi world and about kaguya.[9]
Sasuke was bothered by the story of Kaguya, and questioned the things she did. He couldn’t understand why she would need to create a white zetsu army, if IT was meant to be the start of a peaceful era. So he used his travels to also learn anything and everything about the nature of the world he’s in, and hopefully get closer to understanding Kaguya' reasoning for why she needed an army. His information usually came in the form of his communications with the leaf and allies[10]
about ongoing/current affairs.[11] Plus with the recent discovery and deciphering of kaguya’ scroll, Sasuke learned who kaguya pursuers were and where to find them. He also learned the reason they were after kaguya, and how she betrayed her clan, something Sasuke’ all too familiar with because of Itachi.
My Prediction:
Just as Kaguya' perception changed as she became the rabbit goddess, I believe Sasuke' will continue to change as well as his character evolves. I believe that as the progenitor of chakra, Sasuke sees a link between Kaguya' actions and his own darkness. I believe Sasuke is looking for a way to reach Kaguya' home world to further understand the ways of her and her clan, intern learning about the darkness inside him. I also think that by Sasuke taking Boruto as his student, hes making yet another connection which will ultimately test his control over his darkness. I believe that Sasuke' journey will lead him down one of two paths:
1. Learning to control his darkness and in a moment of confusion loses sight of what’s important.
2. Failing to control his darkness and in a moment of weakness gives in to his impulses, again becoming consumed by it.
and in doing so, he will become part of that which Boruto is prophesied to dispel.[12] Sasuke will die by Boruto' hand, it will be Jiraiya Vs Pain 2.0, but the teacher is the bad guy this time. Ok maybe NOT ALL of that will happen, this could just as easily be the setup for the Naruto vs Sasuke rematch we've been waiting for. Still, like most of my predictions, I do believe this outcome is possible. Mostly because it's been decades since Sasuke was saved from his darkness, he's nearly doubled in age. In that, he is long due for another test of his impulse.
Open Questions:
1. Do you think Sasuke ever learn to fully control his darkness?
2. Why would Sasuke take Borate as a student if he knows the danger of his darkness could creep up on him?