It starts years and years ago, when Kisuke is still officially Third Seat and unofficially lieutenant of the Second Division. He's returning from a long-term solo mission, messier than usual, dark clothes still stained with blood, and all he wants is to collapse into bed and maybe not wake up for a decade or so, when he hears a distinct noise of pain somewhere out of sight. He thinks about just ignoring it, but when he concentrates, the flutter of reiatsu isn't quite like any soul he's ever come across. Different in a way he doesn't recognize, and for all that he's exhausted down to the bone, he is still curious by nature. He figures he might as well investigate. It isn't too far out of his way at least.
So he goes, follows the sounds of a struggle, and stumbles on a sight that at first he's not sure isn't a hallucination brought on by exhaustion and lagging adrenaline and possibly blood loss. In front of him stands three ogre-like humanoid beasts, and Kisuke only has a moment to wonder if maybe they're a new type of Hollow before he spots what two of them are pinning down with clawed hands while the third advance, hunger writ large on its brutish features.
It's a pipe fox. Or at least Kisuke assumes it's a pipe fox, orange-furred and about two feet long. He's never met one, and up until this point, he always thought they were a myth, but hell, he's a Shinigami living in a city for dead souls-- he probably doesn't have much room to throw stones.
The fox screeches again, twisting and turning, trying to free itself even as the beasts - oni? why not - draw more blood, staining the grass underneath. The fox thrashes again, harder, and when its head turns in Kisuke's direction, Kisuke catches its eye, large and amber-gold and full of a desperate sort of fury.
And Kisuke moves without really thinking about it. Maybe he's more tired than he thought. Maybe he feels a foreign pang of sympathy for the pipe fox, outnumbered and cornered by creatures clearly intent on eating or at least killing it.
The oni aren't expecting him but even so, the last one he kills manages to score a long set of gashes along his shoulder before Kisuke beheads it too. It crumbles, like the others, into a dark smog-like pile before dispersing into the air, and he turns around just in time to see the kudakitsune stagger into the air and dive through a portal made of red and black flames before that too winks out of existence behind the fox.
Kisuke stares for a long moment, then heaves a sigh and sheathes Benihime again. It is way too late - or early - to deal with supposedly mythological creatures come to life. He can rearrange his perspective of exactly how big the universe seems to be after he gets home and gets some rest.
Later, once he's a little more awake and a lot more refreshed, he berates himself for not at least capturing one of the oni for further study. He thinks longingly of those unique red-black flames that kudakitsune could apparently produce, but he never sees it again, or any other supernatural creatures for that matter, even when he goes back to that clearing. Even the fox's blood was gone, washed away by rain.
He drops a few hints, to Yoruichi and Tessai, and later to Hirako and even once to Kyouraku once he becomes a captain and has more reason to strike up conversations with his colleagues, but none of them gives any signs that they know anything about the existence of creatures that aren't Hollows, and eventually, Kisuke gives up on that line of investigation.
Decades later, years after the first and last time Kisuke saved a pipe fox from oni and has long since half-convinced himself that he imagined the whole thing, he's out in Rukongai, inwardly panicking as over half a dozen captains and lieutenants scream and writhe in agony around him, slowly but surely and brutally Hollowfied without warning, while Aizen smiles and turns to leave with Tousen and that Ichimaru boy, and Kisuke can't see how this night won't end in anything but disaster.
A flash of red-black flames roar into existence over their heads, everyone who still has their wits about them turn to look, and so they're all in the perfect position to see a bright orange kudakitsune spiral out of the portal, teeth bared and eyes a bright piercing gold as it lunges straight for Aizen.
Aizen's eyes have gone wide, but he still has the presence of mind to raise a hand, Kidou already sparking at his fingertips. It does him absolutely no good though, because between one blink and the next, the kudakitsune shifts, its body blurring around the edges for a moment before bursting outward in a blaze of gleaming flame-coloured fur, a black mane, and four giant black tails that rise behind him, red balls of flame already forming at their tips. The fox flings them all at once, and they grow in size to engulf Aizen and his two subordinates in a wave of dark crimson, shattering Aizen's retaliatory Kidou spell like it was nothing.
The kudakitsune - turned four-tailed kitsune - soars around the inferno once, twice, three times, and when the foxfire finally pulls back, all three Shinigami are singed and sprawled on the ground, their wrists and ankles are bound with flame, and a collar of the same has wrapped itself around each of their necks. Aizen seems to be shouting something, looking enraged for the first time Kisuke has ever known him, but no sound comes out, and Kisuke catches a glimpse of intricate red runes glowing faintly in a circle around them.
On his part, Kisuke watches in astonishment as the fox lands lightly on the grass, not bending a single blade even as more runic symbols stretch out from beneath its paws toward Hirako and the others, and one by one, they fall silent. Kisuke would be worried that the fox has killed them, but he can sense their reiatsu calming, as well as see their grotesque half-transformations fall away and crumble to white dust and then to nothing around them, and he has no idea how, but he knows the fox is reversing the Hollowfication.
When even Hiyori falls into peaceful unconsciousness, no longer in danger of dying, the fox finally turns to peer at Kisuke with large inquisitive eyes. Its mouth doesn't open but a distinctly male voice echoes around the clearing– “A debt was owed. A debt is paid.”
Kisuke stares for a moment longer. And then his shoulders sag a little with sheer relief. Beside him, Tessai shifts his weight, brow creasing a little with worry but Kisuke waves a hand in reply. “It's fine, Tessai-san.”
A debt. One that the fox took into account and has apparently not forgotten, even after all these years. Then again, a handful of decades is probably nothing for a creature that's probably lived at least four hundred years and will live quite a few hundred more.
Kisuke inclines his head, respectfully. Sitting up the way it is, the fox's head is level with Kisuke's shoulder but its tails loom high over all of them, and Kisuke has just witnessed firsthand what the fox is preliminarily capable of. Besides, all the stories caution against offending kitsune, especially one with even just four tails’ worth of power. “I thank you. You did not have to do this much, but I am grateful for the assistance.”
The fox's head cocks, then it rises to its feet and makes its way over. Both Kisuke and Tessai tense, but not as much as they could have. There is no killing intent in the fox anymore, and in another second, its shrinking once again, back to its pipe fox form.
“You aided me when you had no obligation to do so,” It declares. Its voice is several pitches higher in this form. “It is only right for me to return the favour in your time of need.” It glances back briefly over its shoulder at Aizen, who's simply fuming in silence now. “Is there anything more you need of me while I am here?”
Kisuke hesitates, because he's not sure if this is the same favour or a different one, and however harmless the fox seems to him right now, it very much isn't, and Kisuke isn't in the habit of falling into anyone's debt so easily. The fox blinks at him though, and when it speaks again, it sounds amused. “Assistance freely given, human. Consider it the same debt, if it makes you feel better.”
Well, that’s good to know. And Kisuke does want to see that flame portal again...
“Could you transport us back to Seireitei? To the Twelfth Division?”
The fox considers him for a moment. “I can transport you anywhere. But where is this ‘Twelfth Division’?”
That question results in a quick description of Kisuke’s squad compound, complete with hand gestures and a hastily sketched picture in the dirt that the fox noses curiously at before copying with a flick of its tail that produces impressively accurate illusions all around them.
Kisuke has so many questions.
But they can wait for later. Hopefully, the kudakitsune would be willing to stick around for a while longer. In the meantime, a portal of red-black flames open, and Kisuke begins the arduous task of slinging unconscious Shinigami over his shoulder and taking them back to his labs for a checkup.
At least Aizen hasn’t escaped and left Kisuke to take the fall for the clusterfuck that would’ve been tonight without the fox’s intervention.
Kisuke wonders what kitsune like. Udon? If that turns out to be true too, Kisuke will buy the fox a year’s supply of the stuff just as soon as this mess is sorted.