This movie made me even more curious after reading today's chapter. Let's make a wild guess and factless theory :) (Dear Mods, please let me know if this post is inappropriate to be placed in this threads, I'll delete it accordingly).
What if, when Naruto and Sasuke meet their destined moment, none of them could win and they eventually made a pact / agreement to end the cycle of hate?
Sasuke would offer to end the cycle of hate by being the 'hokage' / ruler of all Shinobi, at the cost of Naruto being banished or secluded himself from Shinobi world. Naruto considered the offer and together they freed up all the Shinobi trapped in Infinite Tsukiyomi (join effort to perform the seal), and then Sasuke tell everyone a different set of story...
He would tell everyone he's the savior of the world, while casting Naruto away (either declare him as dead or cast some jutsu). The only witnesses alive are Kakashi and Sakura, and probably Sasuke could just cast a jutsu at them to modify their memory. Literally writing a history to his own benefit at the same time breaking the cycle of hate...
... and then this story is about Naruto's journey afterwards. And how his friends, especially Sakura, felt that something is missing and goes to search for him.
'The Last' can be associated with different vibes and theories... it could be the last jinchuuriki, the last 'survivor' of the war, the last / true hero, the last journey to become a hokage or the last fight to regain his deserved hokage title. If 'Road to Ninja' starts with a question about 'What is Shinobi?' and ends with a poetic answer 'Shinobi is those who endures'; then 'The Last' could be pretty interesting to follow...
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"I'm sorry I didn't believe. But I'd given up believing in so much, until I met you. From the first day I saw you, you were everything I ever wanted to believe in. You can do this, Diana. I know you can...But I have to go."
"What? What are you saying?"
"It's okay, this is what I came here to do. I can save today, but you... you can save the world."