Shunsui has lost Jushiro - and Yama-jii, and Retsu, and...
It doesn't show. He doesn't seem older.
He should.

So...
This is both a fic about mourning, and about how aging works in Soul Society, because hell, it makes sense to me. And I'm a little bit good at making things trajic in whole unexpected ways, I hope.

(To be clear, I don't think Kubo has really worked out a canon explanation for souls aging, and I don't think it's much of a problem at all, since there is no plot point about it. I just like to figure things out even when it seems all over the place.)
(same thing, I've worked out my own personal Bleach timeline, always following what canon gives us, and interpreting for everything else, and I'm planning on using it consistantly in my Bleach fanfics, even if it doesn't always have much impact on the various pieces I'm writing.)

tags: Kyoraku Shunsui & Ukitake Jushiro, Kyoraku Shunsui, Ukitake Jushiro (mentioned), Yamamoto Genryusai (mentioned), Unohana Retsu (mentioned), aging, grief/mourning, canonical character deaths, chronic illness

How the years take hold

Shunsui was vaguely surprised to find – after everything, after Yama-jii, after Retsu, after Jushiro – that his slight wrinkles – if you could even call them that at this point – were barely more marked. He supposed, were he to take a picture of himself today – now that Bach was defeated, now that everything was over and done with – with one from before the Winter War – Aizen's arrogance and his will to have as many witnesses of his ascension to godhood, at least, had saved lives, if not their self-confidence, whereas Juha Bach's... – that he'd find some slight differences, signs that his body had aged, oh, what, perhaps a few months, maybe a year as a consequence of everything that had happened.

Jushiro's death – and Yama-jii's, and Retsu's, and... – deserved more than a few months of aging.

And yet.

After all these years – two thousands, one hundred, twenty four years since he'd been born as a citizen of the then-newly-founded Seireitei – his body barely looked forty, maybe. Chronological age and bodily age did not work the same as in the Living World, when you were a soul with a body made of reishi instead of molecules.

Oh, sure, the first years of life went about the same as with humans. More or less, children reached adulthood by two decades – unless your name was Overachiever like Nanao-chan or Hitsugaya-kun, and you overexerted your power training while your body had not yet stabilized into adulthood, in which case it could take up to several decades to grow up correctly. When a soul stopped aging visibly, they were considered adults, physically speaking.

Shunsui, just like Jushiro – worse even for Jushiro, considering his health – had taken a few more years than usual to finally reach bodily adulthood, if only because they both had a high amount of reiryoku to begin with, and that tended to cloud the waters when you were still growing up – Jushiro's spiritual power had never stopped growing, not with him needing to use it again and again, always, more, just to stay alive, and that had caused Shunsui's friend to stabilize into adulthood only by the time he was chronologically forty years old.

Once a soul had an adult body... That was were aging became complicated.

Mostly souls just didn't grow older, no matter how many years passed. Or at least, they didn't get older without reason, or for the only and usual reason that was the passage of time.

There were ways, since a few centuries ago and thanks to the fourth division, to determinate precisely how "human-old" a soul's body was at a precise point of time – rather than just estimating by eye, which wasn't always very accurate. Shunsui could go to the fourth division – where Retsu wasn't, not anymore, never again, and he had been the one to make it so, even if Juha Bach had forced his hand – and they'd be able to tell him how many days exactly his body had gained since the last time he'd had a check-up.

He wasn't particularly insterested.

He didn't want to be able to... quantify the death of his closest friend, of his mentor, of his senior.

One of the most common ways for souls to gain a few months – nine, at the very least – to a few years – up to nine years, if the records were to be trusted – was, to put it plainly, pregnancy. Or more accurately, having a child, as both parents aged even if the mother was the only one pregnant. The higher the reiryoku of the child, the older the parents got. Byakuya-kun's father, Sojun, had taken almost six years by the time his son was born. Jushiro's own parents had gotten quite a few years on them that way too, in between Ju-chan's high reiryoku and his seven siblings, though their spiritual powers had been weaker than their eldest brother's. Shunsui also suspected that, had Kurosaki Ichigo been born in Soul Society instead of the Living World – however that would have happened – Isshin and his wife would have aged a lot, perhaps the whole nine years limit, through the pregnancy.

Now that he thought about it... Wasn't Aizen's birth the last one to be recorded with such a massive aging for the parents?

Nevertheless. Shunsui's body had taken roughly twenty years since he'd reached adulthood, and he was pretty certain none of those years had happened through a nine-month pregnancy – yes, he liked to sleep around occasionally, but he was prudent, thank you very much.

Which meant that particular way of aging had nothing to do with his personal aging.

The other way to get years onto a soul's body, though less obvious than having a child, was the one that generally got everyone eventually – everyone who died of old age, so, generally speaking, not shinigami. Though Byakuya-kun's grandfather, Kuchiki Ginrei, had died in his sleep, but that was an entirely different story, one that was quite disheartening, considering he'd been barely past four hundreds, but responsibility did that to a soul, and the Kuchiki were nothing if not overly responsible.

Yes, souls did not age with the passing of time.

No, they still aged because of the passing of time.

Humans called it having an old soul, Shunsui believed. Or was it being disillusioned? Becoming aware of the world's cruelty? A bit of all that, probably.

A soul grew in age whenever a new wound was inflicted upon it, be it literally or not.

Everytime your principles were crushed, for some – generally people you'd call principled; people to whom their principles mattered above much everything else. Jushiro had probably taken half a decade because of that, a few days here and there, each time someone disappointed him deeply, each time he was reminded of how hard the world could be, and all these disappointments came and put themselves on top of the ones that had come before. Because Jushiro was someone principled.

If you asked Shinsui, he'd probably aged, like, half a day because of principles, himself – then again, Shunsui wasn't the most honest person available, so perhaps you shouldn't ask him, and rather ask his best friend, Ukitake Jushiro. Except Jushiro was dead, now, so you couldn't ask him even if you wanted. Which meant you were stuck with your own impression of who the current Captain Commander was – the second one only, in all of the Gotei's history, because Yama-jii had held on for twenty-one centuries, but now, now he wasn't here either, now, was he? – So, your own impression, and Kyoraku Shunsui's lies on the matter.

How many days – weeks? Months? Probably not years, that seemed a bit too principled for him – would you guess Kyoraku Shunsui had aged because of what he believed in?

There was a theory running around, too, that souls could age a bit when they went through a personal, profound transformation. The kind of situation when someone would say something, and their friends would look at them appreciatively and say "well, you've gotten more mature".

Personally, Shunsui was pretty sure that this was the other face of the same coin – the wound was, perhaps, not quite as obvious as when someone's principles were rattled, perhaps not as aggressive, too, but people didn't change like that, out of the blue, without a reason.

A lot of shinigami gained a year or two when they first killed something that wasn't a hollow – when the necessity to kill someone, rather than purify a monster, arose. Honestly, that didn't happen that often in times of peace, but well. Peace had been relative lately.

Everytime someone important to you died, too.

Jushiro had, physically, aged two years in about two days when his parents had passed away.

Shunsui had aged one year when his first vice-captain had died – and the next one, six months; and the next one, two months. By the time Lisa had disappeared – had been taken away, experimented upon, sacrificed for mere curiosity – Shunsui barely aged a week when one of his vice-captains died in battle – two had retired, and then had died of old age, but that was different.

People got used to everything, it seemed. Even the death of their trusted colleagues. Two thousands years as a captain and sixteen vice-captains later, here he was.

Let's not talk about all the other soldiers who had died under his command.

Then Shunsui had aged another year when his own parents had passed away. Then another when his brother had, too, twelve decades ago. Then another when his brother's wife had, barely a few years later – executed, for something she had done, knowing what it would cost her. Then...

But no. Apparently, Jushiro and Yama-jii and Retsu didn't warrant a year of his body's time.

Apparently, he wouldn't age from that.

The worse?

He had an idea as to why.

Two distinct reasons. Yama-jii and Retsu, because they were from the first generation. Even for someone like Shunsui, who'd come right behind, they were from another time. They were old. He'd never wanted them to die, but perhaps... Perhaps, even though he'd never imagined they would, it still seemed natural that they'd die before him – as if any of this, as if serving for thousands of years for the Gotei 13, where people commonly died within a century, was natural.

Jushiro...

Aging was a complicated thing, for a soul.

And yet, Shunsui would say that, in the end, there was a simple way to define what made souls age – asides from having children.

Everything that could tire out a soul, really. Everything that weighted heavily on their shoulders, that made them a little bit more hunched, a little bit less enthousiastic.

That was what aged a soul.

Because their body, made of reishi, were much more the reflection of their soul than a human body could be. In principle, it was the same thing that happened when a soul of less spiritual power failed to injure an opponent with greater reiryoku, even with a blade, even with a well-aimed strike. The soul was stronger, and therefore the body would not be damaged.

In the same way, nothing made a soul age quite as much as weariness.

So yes, Shunsui was slightly surprised – in a terrible, defeated way – when he noticed his lack of obvious aging over the losses caused by Bach's assault. He certainly did not wish to be able to quantify Jushiro's death – or anyone else's for the matter – by the number of days it'd cost his body, but perhaps he'd have – not appreciated, obviously not, but still – felt more at ease if his best friend's death had been acknowledged by the aging of his soul.

Maybe he'd have rather been told that yes, this had happened.

What kind of friend was he, that he didn't seem affected anymore, not even by Jushiro's passing? – his sacrifice, his long-awaited supplice, and all that for what? For Juha Bach to cut him down through Mimihagi, to make that martyrdom useless.

But Shunsui knew why.

Jushiro had always, always been going to die, and Shunsui had always, always known it – and by that, he didn't mean it in the way that everything eventually went away. By that, he meant that be it because of his illness, be it because of Mimihagi, or be it because of a fight – probably because at some point, his illness would have flared up at the worst time, and even with Mimihagi's support it would have cost Ju-chan a fight, and the death that came with it – Jushiro would have died in pain, after a life of suffering, and that even if he had never needed to become the Soul King's substitute because he was Mimihagi's host.

Most shinigami didn't die in their sleep, and Jushiro was not the kind to retire anyway. Yet, somehow, the truth of his condition – his health, the secret behind his survival, the fact that it still wasn't enough to keep him going, that he was expending more and more reiryoku only to remain standing – had always, to Shunsui at least, meant that his best friend's death was awaiting around the corner, in a much more poignant way than even the fatality of any shinigami's death.

Shunsui had a hard time mourning Jushiro – because that was yet another way to put it, here, in Soul Society mourning meant aging, and the deeper the grief, the more numerous the visible years – simply because Jushiro had always been living on borrowed time, and perhaps...

Perhaps Shunsui had done his mourning centuries ago.

Or perhaps he'd never stopped, and that had taken, oh, only a few minutes here and there, but over and over again, just a bit more. Just a bit older.

Until there wasn't anything left to give, until his grief had been completed and could not cost him more, even though it had only truly happened less than a month ago.

Because, though Jushiro was dead now – and Shunsui was left alone, but that was another story – at least his suffering had come to an end.

Finally.

After two thousands one hundred and eighteen years of sickness.

Yes, perhaps Shunsui's grief for Jushiro was visible, after all.

Perhaps it showed, just a little bit, just enough to be in each second taken, in the years past adulthood that his body displayed, alongside all his other losses.

When my dog died two years ago, he'd had cancer for a whole year before that, and the thing is, we didn't cry that much when he died, because we'd already spent one year crying and watching him lose energy and not eating (which, considering the glutton he was, was very worrying) and suffering. Yes, we cried, but we cried less than when we'd learned he had cancer.
It felt as if there was no tears left to be cried.

I think that seems plausible concerning Ukitake's less than stellar health record.