Minato should have expected it.
He honestly doesn't know why he still thinks someone can actually keep his senseis in line. It's been repeatedly proven that no one can. Surprisingly, it's often Kushina who has to keep Mizuki in line but when they agree on something, it's futile to stand in their way. He'll deny it but he wouldn't do that anyway. There's absolutely no point.
He wonders just how he came to know this a fact.
How he came to know them so intimately, so deeply.
First he came for the sealing.
He took to it like a duck to water and he could probably leave now - he's more proficient than he expected when he chased after a redhead. But he isn't doing that. He finds himself unable to leave Uzushio. It is a magnet and Minato hadn't known it before but he is magnetic. He was going to leave, eventually. He doesn't want to anymore. He can't fathom the idea of leaving Kushina, Mizuki, Kanna, Mito and the sheer warmth of the island.
The answer to why has been staring him it the face for a while.
He begins to realise when he makes an offhanded comment about his family being dead and Kushina threatens to beat him up for "calling us dead, 'ttebane".
When he stares at her, his mouth gaping wide open, she huffs in frustration.
"You've been adopted, Uzumaki Namikaze Minato."
Minato flees. He's not quite sure how to deal with this. Kanna is of no help at all. She seems to think he already knew so. Minato runs to the only other semi-sane person of the island - Mito. (He runs to Mito when he doesn't know what to do.)
Even this proves fruitless because she simply regards him, a mischievous smile on her face. You can take the Uzumaki out of Uzushio but you can't take the Uzushio out of the Uzumaki. Minato is outnumbered and he knows it. It's like they're all conspiring against him. He shudders at the thought. Mizuki is probably the calmest Uzumaki he knows - when she's actually awake. Otherwise, she fluctuates between practically dancing around and sitting there like the world's too boring for her.
Minato honestly doesn't know how Kushina deals with it but he doesn't know how Mizuki deals with Kushina either so all he does is be glad he isn't in one of their places. He really wouldn't have survived. He shudders to even imagine it.
He will never have to.
Instead, he's stuck with Kanna. Kanna who happily follows his senseis into everything. If he didn't know better, he would have sworn she was the 'little sister' of their group. That would make him the little brother. He finds he rather enjoys it.
What he doesn't (pretends not to) enjoy is all the excursions he inevitably gets dragged on.
In front of him, Mizuki hisses, "Hurry up!"
Kanna laughs, Minato picks up the pace and Kushina comments: "You worry too much."
This a familiar argument, one they've had some many times that Minato knows how it's going to go. It go to the point where the two of them have the argument for the sake of have it.. and everyone else of course.
"Because you don't worry enough!"
Kushina laughs and Mizuki huffs, holding it for a few seconds before joining her.
They are far enough away from the scene of crime that Minato gives in to his laughter too. To his left, Kanna's eyes are sparkling with glee and on his right, Mizuki and Kushina sport matching grins. In front, Mito watches them all fondly.
It is nearly time.
Time for Minato to make his 'graduating piece' as it is.
He can almost sense Kanna's worried gaze so he takes her hand gently. When he is done, he will not, cannot leave her behind. He knows she would come with him but he doesn't want her to have to make that choice. There is no one outside he longs for, no other family so why would he leave?
Shakily, he approaches Mito.
His new seal is a masterpiece and Mizuki has verified that it should work. There is always an element of probability for new seals but if there are any adverse effects, they aren't very obvious and should therefore be minor.
Mito smiles up at him reassuringly.
She has discussed it with the fox - here she notes wryly that it took some time before it was willing to do anything other than rip her throat out - and it has agreed to the terms. Most of Minato's seal relies on its' cooperation. There is a failsafe but as Mito made clear, they don't wish to use it because it would only cause the Kyuubi more pain.
Gently, he begins his work on Mito's hand.
The fox has been neutralised for the time being so while Mizuki removes the previous seal, Minato gets to work on his seal. It is a thing of great beauty, complex and swirly but Minato cannot appreciate its beauty when he doesn't know if it will work or not.
As he waits for Mito to wake up, he trembles worriedly.
Mito must wake up. He needs her to.
She does and Minato has never been so relieved. Even the sudden appearance of a fox next to her doesn't snap him out of it. For a second too long, he thought he'd lost her that she was gone because of him, because his seal was faulty. It would have been all his fault.
The fox looks at him impassively. When it speaks, it growls the words out, "So you're the brat who changed the seal."
Mizuki inclines her head and Minato tries not to stutter as he replies, "Yes."
The fox stares at him a little longer, sniffs all five of them and then slinks away. Minato tries not to worry. The seal should work. The seal will work. He has to believe it. Mizuki believes it and she's even better than him.
"So... what do we do now?" Mizuki ponders, "Kushina, we were going to tell them something, weren't we?"
Minato tries not to react as her thoughtful look twists into a wicked smile.
"Yes, the Chunnin exams, wasn't it?"
Minato huddles with Kanna as they desperately try to escape from his former - as if: current senseis' manic laughter. Mito watches them with her usual calm smile. They all know she's trying not to laugh at their misfortune.