A/N: Was poking some worldbuilding for the background of DtB/Bleach, and Urahara stuck his nose in.

...Who am I to argue with the scariest not-quite-mad scientist out there?

Perched on the restaurant roof, Kisuke Urahara eyed two stars hastily retreating from Karakura's patch of sky, and heaved a partly mock sigh. "Too late."

Partly mock. He'd so wanted the chance to examine a Contractor firsthand. Living humans, rumored among the higher-ups in the Yakuza to have traded their souls for power? Mortals developing supernatural abilities in a way Soul Society had never seen before? How could he miss the chance?

Preparing desperate last-ditch measures against Aizen and the Hogyoku, that was how. Chalk another mark on the ex-captain's long list of offenses: interfering with proper scientific spirit research.

Urahara peered up at the not-stars of Contractors currently in Japan, studying how the patterns subtly changed. Let's hope Aizen's too busy for new research as well.

So far as Urahara's information sources in Seireitei knew, the Gotei 13 hadn't even noticed the Gates opening. Stars in Soul Society were still perfectly normal; the moon rose and set in its proper ancient rhythm. Shinigami who came to the mortal world were too busy chasing Hollows to spend much time looking up, and why would they want to? Everyone knew modern-day pollution blocked out stars that had shone clear and pure just a century before. Ten years was barely a flicker in a shinigami lifetime. Why would they think anything had changed?

A flicker for a shinigami; a long time for young humans, the refugee scientist reflected. Kurosaki's friends probably don't even think about the Gates. One's across the world, unreachable by mortals; the other's over in Tokyo, walled off. The Hollows are here, now, and deadly.

Which had left Urahara in the tantalizing position of a scientific mystery all to himself.

...Yet almost no chance to investigate it. He couldn't stray too far from Karakura as Ichigo grew up. The one time he had indulged his curiosity, traveling to the outskirts of the warp in reality that was Hell's Gate as it shimmered and sang like an unholy siren-

That rainy day, Masaki Kurosaki had died.

Confirming that the energy-patterns of Hell's Gate had an echo of Hollow... hadn't been worth that. Ever.

Since then he'd sat on his scientific urges and stayed put, even after the unknown catastrophe in South America had set Hell's Gate ringing like a struck bell. Unusual as the phenomenon might be, so far it only affected the living world. If he wanted to save all the worlds from Aizen, he had to stay in Karakura to keep the Kurosakis safe.

And Contractors avoided Karakura. Wise of them.

These two didn't.

And that was daunting. Not so much as a risk to Kurosaki and his friends; powers like levitation and force-blades might be lethal to normal souls, but Contractors were still flesh-and-blood mortals and one punch from Chad would put the toughest human down. No, this risk was entirely different.

Urahara looked down at the readout in his hands. It hadn't changed. Damn.

Here, someone reshaped reality.

Maybe. Maybe. This little tablet was meant to pick up signs of Aizen's incomplete Hogyoku, and only more recently and hastily recalibrated to also scan for Orihime's rejection of reality. Whatever had happened on this rooftop hadn't been either of those.

So what was it?

He itched to know. To chase down those traces of distorted souls - they were still human enough to have soul ribbons, no matter how tattered - and shake answers out of them.

But he wouldn't. That might draw Aizen's attention.

Not worth the risk.

After all, if he was right, there was a Contractor out there who could touch the essence of reality. And they couldn't afford for Aizen to snatch up any more hole cards.

So. He couldn't indulge his curiosity yet. But if Aizen was stopped, if they survived...

I wonder what it'd take to hack Astrometrics?

A/N: Spoiler alert. It's DtB canon that BK-201's power is not, in fact, electrical manipulation. That's how Bai and Hei usually used it, and that's what almost everyone (including the Syndicate) thought it was.

In fact, Hei manipulates reality on the quantum level. To the point one mad scientist speculates that he was able to change matter the same way humans are changed into Contractors.

Bunnies: Hogyoku. Orihime rewriting reality. Ichigo's contagious powers. Oh yeah, this so fits...