In one world, Naruto coughs up wet blood onto the hand embedded in his chest, onto the hand that pushes a still-beating heart out of his back. In one world, Kurama's corrosive orange chakra bleeds onto Sasuke's skin, vindictive and clawing for something the Uchiha cannot give. In one world, the strongest of the bijū is held back by a blonde boy with an iron-strong will.
In one world, the Last Uchiha makes himself join the jinchūriki in death.
In yet another, Sasuke puts a hand through Naruto's chest and kicks him through the air. In that world, the jinchūriki lives long enough for them to clash again, to give and take and give and take and lose an arm each. In that world, Naruto lives to fulfil his dreams, and Sasuke lives to fulfil his punishment. In that world, they have children, and their children have children.
In that world, both Uchiha and Uzumaki cross to death hand in hand, with their families standing staunchly by their sides.
In another, Naruto is sliced open by a drunk civilian.
In another, Sasuke is sliced open by Itachi.
And still, there is another-
Ah.
It seems I am losing the tale.
Take a step to the left, shift through an unknown barrier.
In this world, Naruto and Sasuke are Tony Stark and Steve Rogers.
In this world, Naruto and Sasuke are Ashura and Indra.
In this world, Sasuke is born into the searing heat of a World War and feels the tension in the air.
Maybe it is his long-lost conscience that convinces him to become Captain America; maybe it is something else. Maybe it is Naruto, or as much as Naruto can be a shade turned pale and distant by the current of a river.
In this world, he chooses the shield and wields it like a kunai.
In this world, he chooses the safety of the people he loves and drives himself straight into an icy grave, flirting desperately with a woman he pretends to love.
In this world, Captain America dies.
Twenty-five years later, Naruto is born to a hollow-eyed mother and a too-fierce father.
In this world, Howard beats him and berates him even as Tony pushes to be better, to be more. In this world, Howard shatters bottles on his head and breaks his belt on his back.
Tony doesn't break, and Naruto can't help but feel like this is familiar.
In this world, Tony meets Rhodey and Honey Bear, and for some reason, the older man sticks to him and likes him and loves him for who he is.
In this world, Howard and Maria and Jarvis die after Tony turns twenty-one. Naruto mourns Jarvis, who reminds him of ramen and kindness and silver lichen drooping over shadowed branches. Rhodey holds him through it all.
In this world, Tony is near forty when he's captured by the Ten Rings. In this world, Tony is near forty when shrapnel shoves its way into his chest cavity.
That feels familiar too.
In this world, Tony builds the suit and gives himself flight and fire, and that burns like something else. Like Sasuke, maybe, as much as Sasuke can be paper wrinkled and blackened in equal measure.
In this world, Tony lays waste to a terrorist organisation with Yinsen and Sasuke burning heavy in his heart.
Tony drinks and drowns and drinks and meets Pepper.
He sees more than feels the way the palladium in his chest begins to take effect.
In this world, he meets Natalia and sends her back to Nick Fury.
In this world, he lets her approach him from behind and jab him with lithium dioxide.
In this world, he feels the spiderweb of palladium poisoning spreading from his chest.
In this world, he doesn't tell them that the poisoning isn't what's killing him.
Sasuke comes back to life with a gasping breath, and orange and warmth and Kurama.
For a fleeting moment, he remembers a smiling face with whiskered cheeks and thinks – Naruto.
Except it isn't, because it's a man that introduces himself as Nick Fury and reminds him inexplicably of the Hokage.
In this world, Sasuke follows a man who could have been a village's leader in another life and decides to save this new Konoha.
In this world, Naruto and Sasuke first meet in Stuttgart, and with Loki playing catalyst they explode into their first fight.
They don't have jutsu, but Tony spots the uchiwa carved into the shield and Sasuke sees a suit of metal and fire, and they become Known.
Neither of them acknowledge it.
In this world Naruto sees a vision of Sasuke broken and bruised, and Ultron becomes more than just an idea.
In this world they pick up Wanda and Pietro, and then Pietro dies and it stings because though he was blue he was still a flash.
Wanda gets absorbed into the team, and it hurts but Naruto has always found it selfish to object.
In this world the Sokovia Accords are presented to them, and Naruto is tired. Sasuke is not.
In this world they stand diametrically opposed, foes.
In this world Naruto has Konohamaru, has Kakashi and Iruka and Sakura in not as many people.
In this world Sasuke has Genma, has Sai and Isshiki and Bucky who reminds him too much of his own lost arm.
In this world they clash suit to shield, Rasengan to Chidori.
In this world their allies fall before they do.
In this world Tony's hand goes straight through Sasuke's chest, and Steve's shield embeds itself in Naruto's heart.
In this world, they die by each others' hand.
(In another world, Naruto laughs as he holds the universe in his hands. In another world, Naruto snaps his fingers and bends the story to his will. In another world, Naruto goes out in a blaze of fire and wind and ash, and Sasuke thinks for a moment that he looks beautiful like this, looks for all of a second like the bijū are standing by his side, looks like the same self-sacrificing idiot that he's always been. Then, of course, the burning spirit leaves a body too weak to contain it, and Tony is gone.
Sasuke lowers his head and lets himself mourn what could have been, lets himself whisper a quiet "dobe".
Then Steve ceases to be Sasuke, and the spirit riding on lightning leaves to follow his counterpart.)