Well, got back into this recently, and came up with a... crack-ish sort of generic crossover intro, so... enjoy?

PMMM Crossover prelude

Homura was never the best at forward planning.

Back when all… that happened, there had not been a lot of time to think about what she was doing. She had a very limited window of opportunity and was in exactly the right mind-frame (insane. She had been insane) to try it without wondering too much as to why, exactly, she was doing what she was doing.

It's only after she'd turned the entire Universe into a gilded cage fit for a Goddess that she found a reason to attempt it in the first place.

A relic of her time-travelling personality, she'd thought at the beginning. To address the effect before the cause had manifested itself had been a mainstay of her plans to save Madoka, though doing that invariably turned her reactions to effects that had yet to occur into causes for other effects to take root instead. She had been extremely impulsive by the end of her time in the loops.

But then she'd become a Goddess herself and all thoughts of what she had gone and done that for had become obvious in hindsight;

Madoka had never been what one would call overly organized. Though more punctual and studious than, say, Miki Sayaka, Madoka hadn't had to really organize her own routine very much in life. School laid out what she needed to learn, her parents dictated when and where she needed to be when she wasn't out & about and Sayaka tended to take the lead on where to go and what to do when they were off doing things.

It wasn't really her fault, per se. She had been a teenager when she ascended and going from having her entire schedule and study work dictated by adults to gaining total dominion over all magical girls in existence across the entirety of space & time did not go… quite as well as she'd hoped for.

Homura hadn't been expecting to find the Law of Cycles to be in as much a mess as she did, but she hadn't been too surprised either. Madoka, well, wasn't exactly the best at planning ahead.

For example, when a magical girl died, her Witch didn't necessarily die with her. Instead, the Witch and all the grief that had gone into creating it was absorbed into Madoka's own Grief Seed, which grew proportionately to the amount of grief it had gained.

Back when Homura first saw the thing, it had been the size of a planet. By the time she took over, it was the size of two solar systems and so heavy it acted as the center-point for its very own galaxy.

That… wasn't exactly an optimal outcome. She hadn't lasted for nearly long enough after Madoka's ascension to justify an increase in size of that magnitude.

Then there had been the magical girl system itself. The Incubators, bless their shriveled, rotting little hearts, had endlessly tried to tweak the contracting system into working. When it finally did work, then the Law of Cycles would shift in response, causing the system to inexplicably fail despite almost working once or twice. Then they examined the cause of the failure and discovered that whatever tweaks they'd made had been rendered moot because new errors had popped up elsewhere in the system.

Once or twice could have been explained away. Humans were just so… alien. Different. It was hard to get a handle on them at the best of times, what with being so emotional, adaptable and crazily variable that even they themselves ended up not really knowing what it is they would either want or need five minutes into the future. So errors were expected. Encouraged, even. The more errors addressed early on, the less likely they would become in the future.

That helped explain away the first dozen errors. Not the next million or so.

It didn't take the Incubators long to figure out that their designs were failing by design.

And, for all their alien tendencies, Incubators were just as petty as the average human when it came to getting revenge on someone (or something, as Gods were wont to be either) that was fucking with them.

Hence her former predicament.

Then there had been the absolute capper-Heaven itself. A house, a garden and a patio, large enough to comfortably house the billions of magical girls Madoka would come to collect. It sounded simple on the surface; Each girl got their own little flat and could roam around the grounds without a problem. They could reincarnate if they wanted to. They could go on missions for their Goddess if they wanted to. There were no real rules, per se, more guidelines everyone agreed to follow.

There was no attention paid to the fact that, for all that they were dead, Magical Girls were still human. Still remembered their time on earth. Still held grudges. And happened to live right next to their enemies in a completely unregulated environment where nobody could die, no matter how much they wanted to do so.

In short, when the Goddess and her chosen few were around, everybody behaved. The second they flounced out of sight, prison rules applied.

It spoke volumes that Homura's own Witch's barrier was probably a much safer and more comfortable place to live, faceless familiars and pyromaniac blimps notwithstanding.

Madoka was a nice girl. Niceness mixed extremely poorly with the sort of discipline and enforcement of said discipline you needed to stop billions of teenage girls sharing the same space (even if it was Earth-sized, it still would never be enough for some people) from trying to kill each other over petty stupidities.

Homura hadn't been surprised. The setup was more hopes and dreams birthed into a horrible reality than the orderly, well-maintained structure something that qualifies as a Law of The Universe should be given.

Turns out that giving a teenaged girl the power to warp reality had unintended consequences. Who knew?

It also carried with it the implication that the Law of Cycles was, well, doomed to collapse upon itself. Too reliant on a single point of failure. Too simplistic. Too… well… fragile.

And if Madoka took it badly enough to allow her Galaxy-Sized Soul Gem to blacken and spawn a Witch, then the end of the Universe would come sooner rather than later.

Since that was a threat to Madoka's existence, Homura did, eventually, set out to rectify these design flaws.

And, for once, it worked out. Unlike Madoka, Homura had had to structure her entire life around a self-appointed schedule and stick to it. She'd had to figure out how things worked if only to replicate/subvert them. Everything from field-stripping and cleaning a rifle to interrogating gang members to find their safe houses had ended up on her schedule at one time or another and she'd had to develop the discipline and time management skills her peers had sorely lacked back then.

Fixing broken systems hadn't been something she'd specialized in before becoming the Devil, but she knew how to go about learning how to do such things, so she did.

She didn't really think she'd end up doing things this way, but that was a silver lining of sorts to her selfish act of betrayal. She could set things right. Stabilize the Law of Cycles, rebuild Madoka's Heaven into something more sustainable, keep the Incubators and whatever other horrors the cosmos could spawn from devouring the energy powering the Law, give Her and the others a chance to grow up and learn how to organise & plan ahead, the works.

All she had to do to make that happen was fix the Law, the Universe and the Afterlife whilst giving everyone a natural life-span to live out.

It wasn't even that surprising that Sayaka popped up to fuck with her plans every so often. As in life, so in death it seemed. At least Miki showed she still cared enough to confront Homura directly rather than haring off to do something actually constructive to her goals like, say, waking Madoka up.

Now that would have been the day.

And so she passed the hundred years subjective time (and billion-plus years real time, because fixing that mess was just that hard, goddess, devil or no) alternating between her Universe, messing with the fabric of reality, Madoka-watching, Sayaka-brainwashing, Mami-pleasing, Kyouko-teasing (that had never gotten old when she could pull it off, not once) and Kyubey-torturing.

In other words, she worked. And worked. And worked. And worked. Working over Kyubey for answers, advice and stress relief was fun, but still qualified as work when you got down to it.

In the mean-time, the others grew up, fell in love, either adopted or made their own families, learned about being parents, worked, grew old, retired and died, one by one.

Mami was the first to go. Her love of sweet things had eventually overcome her rationality and, without the calories burned fighting for her life, she spent most of it battling fun things such as obesity and heart disease. Homura tried fixing her, eventually resorting to giving her an aversion to all things sweet (Mami switched to sour, which turned out even worse somehow), but still Tomoe didn't make it to see her sixtieth birthday.

Kyouko followed a decade later.

Nagisa hit eighty and keeled over.

Then… Madoka died, a hundred years and one day old.

Homura had finished her great work of un-fucking the Universe by then. She'd fulfilled her wish-to protect Madoka. The woman had lived a full and happy life and her Goddess self now just had to follow the very simple and easy to understand instructions Homura had left behind for her benefit.

All that done, she'd gone to visit an old folk's home just as she felt her powers wane and her Universe start to unravel at the strain of keeping the Law of Cycles out. She walked into Miki Sayaka's room, called her Oktavia to her face and, just as the old crone sputtered in outrage at what the Devil in front of her had done, shot her in the face with a Desert Eagle.

For old time's sake, of course. The fact that it would give Magical Girl-ghost Miki a centuries-long headache was merely a bonus.

Then, finally, Homura let herself die, crumbling alongside the very Universe she'd created and sustained for so very long.

That was the final act in her grand plan. The pinnacle of her achievement. Her Grief would fuel the Law of Cycles for millions of years, her Seed would purify the Goddess's soul gem for as long as it took for Madoka to get back in the saddle, her work would stabilize the Law, her memory would instill the healthy paranoia necessary for the Girls to detect and fight any unexpected interlopers and her Death would allow her to escape that final, terrible judgement Madoka would have in store for her when she fully awoke to what her best friend had done.

Of course, as her Clara Dolls had endlessly reminded her, any plan one Homura Akemi came up with was a plan that was destined to just up and fuck itself at the very last minute, no matter how powerful she became.

This time proved to be no exception.

And done.