Unknown

Konoha was a big city. The most populous hidden village by a decent margin, and one of the single largest settlements the planet. By the time Sasuke had returned more permanently, these things were even more true.

But even Konoha at its busiest wasn't like this. Especially not at night. People were absolutely everywhere, milling about like ants. Sasuke kind of hates it, and he's up on the rooftops looking down at this mess. He couldn't imagine what it'd be like to be down there, surrounded on all sides by throngs of pedestrians.

Fortunately for Sasuke, he's a shinobi, and thus fully capable of avoiding the hassles of civilian life like waking the streets. He leans forward on his haunches, thumbing the grey fabric of his not stolen Haiori that he bought with his stolen money. He could've just skipped the money part, but even the simple act of buying things was a way to gather information.

Unfortunately, none of it was particularly useful. He knew the country he was in was called Japan, and that this city Tokyo was the capital, and a laundry list of other mundane facts and extrapolations that left him no closer to getting home then he was before.

Sasuke stands, stepping back from the roof's edge. What he really needs to do is start searching dimensions, see if he can find his way home on his own, and just how far away he'd ended up. That the multifaceted space all realities seemed to occupy had such a concept as distance was still mind bending, but far be it from Sasuke to study the structure of existence more than was strictly necessary to master his Dojutsu.

He turned away from the street, facing the center of the building. In any hidden village, he'd be a little more leery of doing this on a random rooftop. But here? He wasn't worried. There were shinobi, sure, but they seemed even more removed from people's lives then any of the hidden villages, and if some patrol was going to accost him then they'd have done so by now.

So, he focuses on his rennigan, feeling it become a blackhole for his chakra as the space in front of him spins and folds. A doorway between this dimension and the next swirled open, dark and lightless.

Sasuke steps through, shrugging off the slight nausea the transition brought. The portal slides closed behind him, and Sasuke find that this world is significantly less hospitable than the last. Red rock stretches for as far as the eye can see and the air feels like sandpaper. He's moving on to the next before he can take it in any further.

And then the next.

And the next.

And the next after that to.

It's on world number 6 that Sasuke stops, because he's already taxed his still recovering chakra reserves more then he's comfortable with and none of these dimensions have been familiar. They don't even have chakra, which means he's farther away from his home dimensions and Konoha then the thought.

Much farther in fact, because when Sasuke sits down to mediate and actually feel the dimension around this one, he does in fact find home. Certain chakra signatures are unmistakable, and his new space time Jutsu may not have extend his actual sensory range by much, but it did let him search though dimensions. Normally only nominally useful, but right now?

Invaluable, and also horribly horribly depressing, because the distance between where he is right now and home is…well, Sasuke has chakra reserves second only to Uzumaki Naruto, but he's fairly certain he'd succumb to chakra depletion long before he got home if he continued on as he had been, hoping from one dimension to the next closest.

Sasuke slowly stands. The world he's in right now is a weird one, full of black pillars reminiscent of what Kakashi-sensei had told him of the Kamui dimension. It's kind of cold and not very comfortable, but it's hospitable.

The same cannot be said of every other dimension he'd been to. If he for whatever reason did continue as he was, and ran out of chakra at an inconvenient time…

Sasuke needed a different solution.

He shunshins up a pillar, and then seats himself at it's summit. This dimensions really does seem to go on forever, and up here there was a small breeze that helped to clear his head. He can't slow boat it across the multiverse. The distance is simply to large, and even if he paced himself, the odds of ending up somewhere be couldn't stay while low on chakra were to high.

Many small jumps were just off the table. But one massive leap? He'd….never done one of this scale before. Hoping over a realm or 2? Sure. The massive number of dimensions between him and home right now? Not so much. Though the more he thought on it, the more Sasuke thought it might just be possible. Not easy, he'd need a truly monumental amount of chakra, but it could be done.

If nothing else, it was his best bet at returning home. The longer he waited, the more likely a certain blond idiot was to do something stupid, the less likely a pink haired medic was to stop him.

Sasuke rose to his feet, Adjusting his haori. If he was actually going to do this probably stupid plan, he needed chakra, and a lot of it. That wasn't something he'd be replenishing very fast here, and so the space before him warped and twisted into a portal, which the uchiha promptly stepped through.

The roof hadn't changed since Sasuke had been gone, save for the shadows sitting a slightly different angle as the moon continued along it's journey. He walked to it's edge, his world rotating 90 degrees as he continued down it's side and into the shadows of the alleyway it shared with its neighbor.

The noise was louder towards the street, and so Sasuke walked in the opposite direction. He needs to think, and navigating throngs of civilians wasn't going to help that.

He needs a way to pool chakra, and a lot of it. More than his reserves normally hold when he's topped off in fact. Moreover, he needs to pool all of that chakra in his Rennigan. Theoretically he could just focus on funneling all of his energy into his left eye, but a single lapse in concentration could have all his progress lost.

No, he needs something more full proof. The closest thing that he knew of was the strength of a hundred seal, but Sasuke's chakra control wasn't nearly good enough to complete it. It'd taken Sakura years to finish, and she was far more precise then he was.

But the underlying concept was the same, so perhaps he could use it as inspiration?

Food for thought if nothing else. He'd have to start experimenting sooner rather then later, because the longer he was a away the worse things would be when He returned. Because he was going to , one way or another. If not on his own power then, when Naruto lost his patience.

It's when Sasuke turns onto another back street that his musing is interrupted.

"It's you!"

The voice is loud, filled with a type of brightness that he can't help but find familiar, and for the scarcest moment, Sasuke worries that Naruto did in fact get tired of waiting and is here to drag Sasuke back to Konoha again.

But when he looks over his shoulder, it's not a head of blonde hair with whiskered cheeks.

No, instead he sees a boy at least 2 years his Junior. His eyes go to the checkered haori first. It's eye catching if only because of the pattern, and highlights everything else strange about the kid. His hair is red for one, a shade so dark it's become burgundy. It matches his eyes and earrings at least, which are almost as out of place as the box on his back and the poorly concealed sword under his haori. There's a scarf wrapped around his head like a hood, and his smile does little to conceal the discomfort.

And to top it all off he's tugging along a girl with a piece of bamboo for a muzzle, who looks like she might just fall asleep on her feet.

He wonders if it's to late to Shunshin, but the boy is marching up to him with the same bright grin on his face and relief in his eyes. It's painful, to see that sort of kindest directed at him. It hurts when he sees it from Sakura or Naruto or Kakashi or anyone else who found it in themselves to forgive him despite everything.

How a stranger can bare such a look for Sasuke he does not know.

"In so glad you're okay! I'm sorry I didn't have time to stay for you to wake up." The boy says. His shine hasn't diminished when Sasuke turns around. If anything, it's brighter, and he has half a mind to squint to protect his eyes.

The boy comes to a stop before him, and now that he's bothering to really listens, the kid's voice sounds rather nasally. "Oh! I haven't even introduced myself, I'm Kamado Tanjirou, and this is my sister Nezuko. I was the one who found you on the side of the road."

Ah, so this is the person who witnessed his humiliation. Sasuke is certain now that the sage can see him now and is punishing him for his past crimes, which is fair. He definitely deserves it, but that doesn't make it any less embarrassing.

"Hn" is all he can muster in response, along with a nod. It's only seconds after he lets out the Uchiha's trademark grunt that he realizes he should probably reciprocate introductions.

"Uchiha Sasuke" he says, and later, he will pin down this as the exact moment he bound himself to this realm with attachments. He'll look back at this conversation and know that it was here the seeds of another bond he could not break were planted.

But In the now? He is still innocent of that realization. And when Tanjirou offers to share a meal with him, suggesting udon of all things, sentimentality gets the better of him. The kid didn't exactly give him much of a choice either, bypassing Sasuke entirely to order two bowls at the stand occupying this backstreet with them.

"So, are you from the city?"

Sasuke glances at Tanjirou out of the corner of his eye. He has no reason to lie, and so chooses to shake his head. Evidently, that simple gesture is enough for his impromptu companion as he hums and nods along. On the boy's other side, his sister is listing further and further towards him, looking like she'll fall asleep at any moment.

"Ah I see. Im not either. Me and my sister come from the countryside actually, what about you?" Tanjirou prods.

Sasuke side eyes the boy again as he deliberates on a response. It doesn't take him long to come to a decision, not when Konoha's name means nothing here and he is not planning to stay long enough for that to change.

"I lived in a village." He responds, and Tanjirou smiles, letting out a noise Sasuke thinks means he's pleased.

"So did my family! Or well, we lived near one. Our home was on a mountain. It was rather cramped with all 8 of us, but we made do." Tanjirou says, something sad-and more importantly, familiar-in his face. With the past tense used, it's not hard to imagine what happened, and Sasuke feels a pang of sympathy for a boy who's family shared a fate so similar to his own.

But then the street vendor is calling that their food is ready, and the melancholy is gone before any words of comfort or wisdom can be offered.

And then their seated next to each other again, this time with bowls of steaming udon in their laps as Nezuko finally gives in to sleep.

"Thank you for the meal" they say in unison, though Tanjirou's voice is far above his own as they snap the chopsticks apart. Sasuke had long since mastered eating with a single hand, but he's hardly got a bite in when the sound of ceramic shattering nearly startles him into dropping it.

There is something in the air, distant and hardly registering to Sasuke's senses, but present regardless. Whatever it is Tanjirou senses it too, seeing as he's standing now, nostrils flared as his looks slowly to the left. His own instincts are screaming now, if only because there is clearly something flying under his radar here.

Sasuke has but a moment to formulate his question before Tanjirou is taking up his sword, and running.