Tasara doesn't know what the Domain was thinking, sending this girl here. Either they're more desperate than she thought, or this girl is extremely foolhardy. Likely the latter. She's, hm, maybe three years out of training, judging by her stamina. Not much finesse, but exuberance in abundance, and a stubborn refusal to admit she's outmatched. If they were further from the city Tasara would flatten her, but the goal is defense, not destruction.
She adds another barrier on the fox's side of the gate and reinforces the one around her and the boy.
He doesn't stop producing the waves for several minutes. They don't seem to actually tired him out, but if he doesn't crack her barrier or boil them behind it he'll subside eventually.
He snorts, eyes her, apparently deep in thought, then flashes his tails forward again - this time sending up a concealing wall of steam.
He's hiding something. She sends her own blast of force to knock away the steam and jolts him through the chains again.
That is enough to reveal, but not disrupt, the massive ball he's forming, which dwarfs him - and he dwarfs mountains.
He breathes - and it rockets towards them so fast the sound of its passage falls behind.
It slams into the gate, flashes, throws them open -
And vanishes.
A man's standing there, who wasn't before. White coat with red flames along the bottom, his back to them. Bright yellow hair, the same shade as Naruto's. His back's to them, and he's standing between them and the Nine Tails, with one arm flung to the side.
"Yondaime!" the Nine Tails roars, quite helpfully. "You bastard!"
"Hello to you too!" the man calls, voice a bit cheerful. He half turns to Tasara, smiles softly, and says, "Thank you for looking after my son. For now, I don't quite have this... I'm faster than him, but I wasn't able to beat him the first time around, even at full power... But I'll do what I can to help."
"Stay here, then."
She flicks the chains and they go rigid, pushing the fox upright instead of holding him down. Gathering magic around her, she launches at the monster in a luminous streak, aiming to push it back into the recesses of the cell away from the other two.
He snarls, and the air in front of her turns into shockwaves. He's clearly able to track her, no matter how fast she's moving.
She arrows through, matching the blasts with ones of her own at the opposite frequency. She starts throwing energy missiles that curve around and attack from all directions.
He destroys most of them with his tails, but a few hit, making him grunt.
He swipes at her, claws creating shockwaves as they pass.
Tasara is fully on the offensive, the blur of her movements merging with the bright lances of her attacks so it seems like she's everywhere at once. Even if the monster can track her, it does no damage and any time she's knocked off course she simply weaves the momentum back in to the flow of her dance.
The key question in a magic fight is who can keep up the offensive longest. Right now, it seems that's her.
It really doesn't help the fox's frustration that all of his large attacks keep getting teleported away by the Fourth.
Chains wrap around him - ones not caused by Tasara - that seem more effective, more targeted, than the ones she'd made. There's a woman standing on the surface of the water, shouting something indistinct and angry at the fox.
More help, apparently. A part of her not occupied with the immediate rush of combat wonders how many people this boy has inside his head.
"Take that you furry asshole!" the woman shouts, adding more chains to an increasingly irate demon fox.
The newcomer is able to decisively swing the battle in the favor of Naruto's allies, and soon enough the fox is fully restrained.