There is a small blond boy who wanders the village alone. It is not safe at the orphanage for him - he is too easy to find there - so he sleeps in hidden rooms in dark alleys in different parts of town every week. There are shadows charged with protecting him, or, more accurately, keeping him alive. But what do shadows care if the boy is hungry or lonely or sad as long as he is still breathing. Anyway, shadows are to remain unnoticed so the thrown rocks and refusals to sell him food go uninhibited. The boy is too skinny with dark bruises and he is still breathing.
If the villagers could look past their hatred for a demon, they would see a remarkable resemblance to their beloved Yondaime Hokage...the man whose newborn son coincidentally disappeared on the same night Naruto was born and the Kyubi was sealed.
If they could overcome their bitter hurt, they would notice the Uzumaki crest, the clan of the Yondaime's wife, adorning all of the boy's clothes. They would notice the characteristic round face and wind chakra nature to go along with his last name.
If they could ignore their misguided anger, they would see a lonely boy who is friendly and polite when given the chance. They would see a boy who is always smiling even though Kami knows no one has ever given him a reason to.
If they opened their eyes and just looked a little closer, they would see that it is an insane smile. It is a smile that says nothing is okay, but maybe, if he can smile just slightly wider, if he can hold it just a minute longer, maybe one day it will be. It is a smile that says no on has ever smiled back at him.
It takes over a decade but eventually they do notice that he is a boy who makes promises and keeps them. They see that he is someone they can trust, someone who has saved their lives more times than they know. However, they don't realize that this teenager only makes promises to distract himself from the fact that no one ever promised him anything.
The boy still smiles constantly. He smiles through missions and war and hospital rooms. They still don't notice that there is something off about it. It's as if he is trying to make up for all the ones he didn't receive as a child. It's as if he is worried that, if he stops now, he will never see another one again.
Another decade and he is just months shy of fulfilling his greatest promise, the only promise he has ever made for himself. He is about to become Hokage and this is when they finally remember a sad skinny boy covered in bruises. They see a shadow of that boy in the great hero who collapses at the village gates, bleeding out and carrying two unconscious comrades. They see the small lonely boy dressed in rags in the image of their future leader when he mourns at the memorial stone for the one teammate he couldn't bring home.
But still, none of them can truly see the pain and fear tearing at the man in the white robes because they cannot understand what it felt like to be so completely alone for so long. They will never understand how his childhood is his greatest fear. How every mission, every death, is a step closer to his nightmares, to his past.
It takes a lifetime and the sacrifices of a small boy but they finally learn something, something that sticks. So when the most powerful and revered Hokage in history dies (and saves them all once again) and the Kyubi is sealed into a mysterious orphan girl with green eyes and black hair and no name, the little girl is adopted the next day. She eats dinner every night and goes home to a family and no one ever calls her a monster. She does, rather lovingly, adopt the nickname "Kit". Her smile is soft and honest and natural. And, if he could have been alive to see it, the great heroic Hokage who was once a small broken boy would say that this is his greatest legacy, that it all just may have been worth it.