Maybe it's the seal. Maybe it was just the slightest imperfection in the writing. Maybe it was the boy's own body rebelling. Maybe, maybe, maybe.
Whatever it is, the cage bars are wide, easy enough for someone as determined and quick as the fox to slip through.
And he does succeed eventually, after the boy he's trapped in ends up bleeding out, ends up praying to whatever deities there are that he'll survive.
The fox wants out, is willing to overwhelm his jailer's mind, is willing to forcefully occupy the frail mortal body he is trapped in.
That's what he intends on doing. That's not what happens.
Maybe the boy fights back in his dying moments, maybe his will is stronger than the fox expects.
Whatever the case, the fox and boy aren't so separate anymore.
Naruto learns quickly to be careful not to say we or us when they talk. They're careful to hide any signs he isn't normal, isn't right.
The boy of before wouldn't understand, but they do.
They throw themselves into learning, the boy's fierce determination and the fox's knowledge coming together.
"I want to be a shinobi," they declare when asked just why they're studying so hard, biting back the we that lingers in their mouth
They enter the academy with abilities they shouldn't know, knowledge they shouldn't have, signs that they aren't right anymore tucked close to their chest.
They feel close to breaking by the time they're assigned a team.
Sakura is the first to notice how they frown when she calls them him, the first to ask if they're a girl or if they want different pronouns.
"We" they say, "us, them," and Sakura smiles in response.
Sasuke is next, frowning when they make him promise not to say it around the adults. He doesn't understand but he's willing to try.
It's not until they're in Wave and sensei is out scouting that they lean close and tell their teammates about jinchuuriki, about the attack on Konoha.
"Is that-" Sakura asks, "is that why you want plural pronouns?"
"Something went wrong." They eventually decide to say. "Something went wrong, and now we're not an I anymore. We are...we are me."
"No one can know" they whisper, "no one can know we're wrong, that we aren't Naruto and we aren't the Kyuubi."
Sasuke swears, Sakura swears, and they feel something in their chest tighten. For once it isn't fear.
Meeting Gaara is a surprise, realizing he has their sibling trapped in him is a bigger one.
Gaara and Shukaku are obviously separate and they wonder if that's what drives the boy mad, wonders if he'd be sane if he were like them.
"It must be lonely" they finally tell him.
Teal eyes stare back and they find themselves talking more.
"It must be lonely to have two people in one mind, to not be able to decide just who you are."
"It must hurt you brother."
"Kurama?" the other jinchuuriki asks, hope swelling in his voice, and they shake their head.
"We are not him. We are not Naruto either. We are me."
"How?" the boy asks, their brother asks, and they shrug.
"We can't remember. We think we're better off not knowing."
They hesitate, wonder if they should, before reaching out a hand and settling it on Gaara's-on their brother's-cheek.
"We missed you."
Kakashi confronts them after the chuunin exams.
"Where is Naruto?" he demands, "Where is he?" he hisses, holding a kunai to their throat.
"We are Naruto and we are the Kyuubi" they respond.
"We are, we have always been."
Sensei blinks, sees no lies in their words, and sheathes his weapons.
They only shrug in response. They cannot remember a time before we and us, they can't remember being two separate beings.
They are, we are, as simple as that.
The sage isn't the one that notices, it's one of his toads.
"You smell wrong" it says, looking up at them, and they shrug in response.
"What do I smell like?"
"Fox and human, but not."
Jiraiya looks up at that, narrows his eyes, and they wonder just how to explain it.
"Our name is Naruto" they finally say, watching the man's brow furrow.
"Our name is Naruto, but we are not him."
They ignore it when he tenses.
"We are not the fox either."
The man blinks once, twice, before responding.
"Your minds are melded?"
They bite their lips, wondering just how to respond.
"Maybe? We are both and we are not at the same time."
Jiraiya asks endless questions, asks how, why, what does it feel like, questions that make it obvious just what he plans to do.
"We are me!" they finally snap at him. "We do not want to be cured, we do not want to be separated!"
They don't speak to him until he apologizes. It takes two weeks.
They're fighting the Akatsuki when it happens.
There's a hand clenched around their wrist, rooting them in place, and they're busy struggling until a burst of pain-pain-pain.
And then they-no, then he-blinks open his eyes and screams.
He falls to the ground and screams, screams and cannot stop.
They are gone, Kurama is gone, and he is broken.
Sasuke and Sakura pick him up without flinching, carry him back to Konoha as he sobs and screams and vomits on their shoes.
He needs him back, he needs the fox back. He can't be alone in his head, he can't, he can't!
The hospital sedates him, lets him live in a blurred haze for two weeks. Two mind numbing weeks until his team returns.
They tell him they can try to put Kurama back, they tell him there's a chance of death or madness.
He would prefer it to the emptiness his mind's become.
He says yes.
There is a boy standing in front of a cage.
Slowly, oh so slowly, the boy reaches out and unlocks the gate.
The caged fox moves before the boy can react, swallows him whole like it did years before.
A moment passes, a moment where the boy struggles and the fox fights back.
A moment passes, and then they are whole again.