Using the code for the current universe, you were able to deduce something. The final four numbers were the ones you needed to figure out, and if this very similar universe was coded at 1700-8915-8730, that meant L's universe would be a few numbers either before or after 8730. So 8729, 8731 or something close to that. That narrowed things down a lot, but it would still be a little trial and error.

"Let's try 8729 first, if it's too different we'll know we have to count up and not down" you suggested.

"Good idea" L replied.

Back sitting in your little bag that hung on L's shoulder, there was some extra weight to said bag. Now full with some food, water and other basics graciously provided by his gender swapped counter part.

"Good luck, it was definitely an enlightening experience to meet myself, just slightly different" L's girl self said.

"If for whatever reason you end up back here, you're welcome to come by again" Quincy added.

"Thank you, take care of yourselves" L smiled.

It felt kind of like saying goodbye to family members, there was still a lingering feeling of disbelief on everyone having met their alternate counterparts. It's definitely not something that happens everyday. But you and L had to make tracks, so with the thanks for the help and a final good bye, you were off. Punching in the code to your next universe and hitting enter, L and everything he carried including you, were quickly zapped into the next universe across.

The cold of England was immediately replaced, the moment he landed in this new universe he found it was hot. The sun was out, the sound of city life wasn't far off and he found himself standing in an alleyway.

"So... a city? Where exactly?" He muttered.

Stepping out into the streets, he immediately noticed the hiragana on the street signs. He was back in Japan, but this wasn't the hotel he was taken from. This looked like a much more rural city. No where near as packed as somewhere like Tokyo. His first thought was to find a train station, from there he could look at the train line maps to figure out what prefecture he was in.

"This can't be my universe. It's summer, way too hot. It's winter back in my version of Japan" he muttered.

"I was just thinking that" you replied.

It dawned on L that talking to you while out in such a busy city while definitely look a little weird, and a moving 'picture' on a bag would draw unnecessary attention. He shifted the bag on his shoulder to hold you closer to him, so you could talk more without being too noticeable.

"Keep the volume low ok? I really don't want to be caught by someone with a literal cosmic being in my bag" L muttered.

"Right yeah, shutting up now-" you replied.

Luckily because of how good Japan's train system was, L was easily able to find the nearest station. According to the map, this was Yamagata. Costal, not super densely packed but not a completely empty spot either. Right in the middle of the city though, it seemed much busier than it actually was.

"Yamagata... never actually been here, what about this place is linked to my universe though?" L muttered.

The last universe made sense, he landed near wammys and it contained his gender swapped self. So what was significant about this one? As far as he knew, he'd never been to Yamagata or knew anyone from Yamagata that this universe may have swapped his role with.

"Yamagata... Yamagata... what is significant about Yamagata?" He pondered.

"Lawliet! Get back here!"

He jumped, still not used to hearing people call his real name. Looking around for the source, he was met with a kid rushing past him followed by presumably their mother. The child, mesmerised by the sign on a store advertising a brand of confectionery, was promptly scooped back up by their mother.

"Jeez Lawli- you run fast!" She said.

"Mama!! I want the strawberry ones!" The child replied.

It suddenly dawned on L, upon seeing the child's face. That was him. He was looking at his child self, although it seems in this universe, he wasn't raised in Winchester, but Japan instead. Which wasn't that strange to think about, he was half Japanese. It seems this universes twist was which part of his mix he was raised in. The lady though, notably didn't look like him. Her hair was a dark brown and not black, she was short and slightly tanned compared to him.

Perhaps, she was a foster parent? L was still an orphan, just one in Japan rather than England.

Intrigued he had to follow, but he didn't want to come off as some stalker, so he kept his distance while he followed the two over to the train station.

"Holy shit (y/n)... that's me" L muttered.

"Dude you're so cute, so little!" You laughed.

"I guess this universe is 'L is raised in Japan' universe. And so much of my life is different from that one small change... I'm never going to become a detective, I'll never meet my dad or my successors, I might never leave Japan at all..."

He wasn't sure how to feel about it, on one hand it seemed this version of him was having a relatively normal childhood, something he definitely couldn't relate to. And he was glad, that some version of him could be happy as a kid. But he also felt a sense of emptiness, knowing this version of him would never meet his wammys family or have the legacy he has as L. But... maybe that's for the best in this universe? This was Japan in the 80s, he was a little kid with seemingly a nice foster mother, and he could live a perfectly normal childhood.

He wasn't even sure where he was going, when he followed them onto the train and sat beside them, simply listening in for information. But he didn't really care, he would leave this universe soon anyway. But if he had the chance to see how his childhood COULD have been... he'd take it.

"Lawliet no biting your nails, it's bad for you" the mother said, pulling the child's hands away from his mouth.

"Yeah, yeah..." he complained.

"I told you to bring your chewy necklace"

"Oh that's what I forgot!"

L held back a chuckle, looks like this version of him also had a touch of the tism. He did that exact thing as a kid... in his universe. This WAS him as a kid after all. You simply stayed still, blended in with your surroundings acting as if you were just a print on a bag. No one needed to know you were a living being right now. Plus... you had a feeling this was something L needed to see, you wouldn't interrupt him. But you did watch, closely, intently. Taking in his reactions.

The train made a sudden halt, making the passengers stumble a bit. L's child counterpart bumped into him, and it caused the kid to lock eyes with what he didn't know was his older self.

"Ah- sorry mister!" He said.

"It's alright" L replied.

As you expected, the sudden halt was the train temporarily stopping because of an issue on the tracks. The announcement telling everyone to wait a moment and sorry for the inconvenience confirmed it, it wasn't uncommon for this to happen in more rural areas. Fallen trees, animals and other things can make it onto the tracks and cuss a delay.

"Hey... you look kind of like me" child L spoke up.

"Are you part English? I am, that's probably why" L replied.

The woman the child called a mother looked up at him, then back down at the kid.

"Huh, you do look similar. He's half English too, what a coincidence" she said.

You couldn't help but find it somewhat symbolic in a way. Symbolic of what? You weren't sure. But the way L looked down at his child self, and the way the child looked up at him. There was a sense of familiarity, although the clueless kid had no idea why the random man next to him felt so... close. L was literally staring at his past self, even if that was an alternate past. It was still him...

It made him feel a lot of things, most of them very bittersweet. He hoped to the gods, that this version of him got to live the happy childhood he deserved. Because he knew firsthand what would happen to him if he didn't get that, the trauma it brings and the long term effects he still deals with today.

Maybe this was fates way of telling him that he needed to look toward his own inner child more, let him heal, let him play.