Alternate universes. Parallel worlds. Timelines. All of these are separated by a border of reality, keeping the inhabitants from meeting one another. The idea of them meeting together is absurd, as well as borderline impossible.

But this special location was the exception.

Mid-World. This location is the center of the multiverse, where inhabitants of different worlds can converge and meet, without causing catastrophes to the space time continuum.

Some time back, the entity known as System once merged the four worlds together for the sake of a fighting tournament. Despite being defeated, she did it once more, bringing in three more worlds. The inhabitants dubbed this the Phantom Field incident after they defeated her.

Originally, they would have destroyed her and set their worlds back to normal, but they had grown fond of their friends from other worlds. A few even starting relationships despite their short time together.

They decided that, in the end, they would have System atone by finding a way for them to meet together naturally, without being forcefully summoned there. She agreed, and scoured the multiverse to find a place where they could all meet in peace.

It was then that System had come across Mid-World. It felt all the requirements that they needed. She had finally found a place where everyone could meet. She sent messages to all of them with the Keystones they all still had.

Yumi had received a message from her white Keystone that informed her that System had found a place, giving them all a date when they would be able to go there, with the Keystone as a teleportation device.

Yumi had to admit she was really excited at the idea. Seeing not only the friends she had made during the incident, but also... seeing Naoto again.

Kurogane, to be specific, not Shirogane. Everyone always got a bit annoyed at the confusion, but those two didn't. They loved being "Team Naoto" whenever they were paired up.

Getting back to the topic on hand, she couldn't wait to see Naoto (Kurogane) and the others once more. But then she got another idea. She sent a message to Asuka, asking if they could meet up at the park again.

Thankfully, Asuka had some free time and came right on time.

"What's up, Yumi?" Asuka asked.

"Well Asuka... you remember the friends I've mentioned before, right?" Yumi said.

"Of course." Asuka said, recalling Yumi's story. "That whole Phantom Field thing, right?"

"That's correct." Yumi said.

"So what is it?"

"Well, we've found a way to meet together without jeopardizing our worlds, and I was wondering if you and Tanjiro would like to come visit it." Yumi said.

"Eh? Really?" She said excitedly.

"Yes, really."

"That sounds wonderful!" Asuka said. "I'll talk to Tanjiro about it! What time?"

"Well, whenever he's ready." Yumi said. "Time has always been an... oddity, when we travel through worlds."

"Oh, okay." Asuka said. "I guess you're the expert for this."

Asuka went off to go tell Tanjiro. It was fairly late, so they'd talk in the dreamscape soon enough.

Yumi took out the Keystone and held it close, remembering who she would see again.

"Naoto..."

The day had come. Asuka and Tanjiro met up with Yumi. Tanjiro was really excited to meet inhabitants from other worlds, as was Asuka.

"Are you both ready?" Yumi asked, holding her Keystone.

They both nodded, was Yumi closed her eyes and concentrated. There was a brief flash of light, blinding them all momentarily, before it died down. When they opened their eyes again, they seemed to be in a place akin to an airport. Of course, Tanjiro didn't know what an airport was, much less airplanes, though Asuka got a good understanding of the area.

"We're here..." Yumi said.

"Hey! I was waiting for ya!"

They all turned to see a young man waiting for them. He had stylish brown hair with a single one inexplicably sticking up. He had brown eyes and a friendly smile. He was dressed in mostly black, wearing a tight fitting short sleeved coat that actually exposed a bit of his stomach.

"Naoto!"

Yumi ran up to him, where she took his hands. They looked into each other's eyes.

"Told ya. I told you I'd keep my promise to meet you again." He said.

Yumi smiled, hugging him. Naoto noticed Asuka and Tanjiro.

"So, you wanna introduce me to your friends here?" He asked.

"Of course." Yumi said, stepping back. "Naoto, this is Asuka, and her boyfriend, Tanjiro Kamado."

"Any friends of Yumi are friends of mine." Naoto said. "Nice to meet ya both!"

"Likewise." Asuka said, briefly bowing.

Tanjiro on the other hand, smelt the air around Naoto, causing the boy to look a little confused.

"I smell a lot of blood, but I can tell you're a good person." Tanjiro said, hand under his chin. "But your arms and one of your legs... they're..."

"Huh, I'm impressed you already managed to pick up on that. But yeah, I lost both of my arms and my right leg thanks to a couple of scraps." Naoto said. "No big deal though, since I did get replacements for them."

"He smells of blood?" Asuka said.

"Oh, that might be because of my ability." He said. "Let me show you."

Yumi stepped back from Naoto, as he held up a hand. Suddenly there was a flash of red, and he held a spiky weapon colored crimson.

"My Drive, Bloodedge, let's me turn my blood into any weapon I need." He said.

"Woah..." Asuka said in awe.

"That's just like some Demons back home..." Tanjiro observed.

"Anyways, we're getting a bit distracted here." Naoto said, causing the weapon to disappear. "We're gonna meet up with the others at Junes."

"Junes?" Yumi asked. "The department store from Yu's world?"

"Yeah. Turns out, this place kind of responds to our thoughts as well." Naoto explained. "It can recreate places from our memory, if want to. It's pretty cool."

"Huh, that sounds a lot like the dreamscape where Tanjiro and I met." Asuka noted, as Tanjiro nodded in agreement.

"Well, we're killing time." Naoto said. "Or... at least as much time passes in this world. Anyways, let's go."

They all walked together, the two couples sticking close by one another. Tanjiro was in awe at all the advancements of the different worlds, as was Asuka seeing how the projections of the worlds had seamlessly fused. She actually wondered why she and Tanjiro had never done that idea back during the dreamscape. It should be possible, right?

They both kept wondering and marveling, until they realized they had walked into the center of a shopping center. When did that happen?

"Yo! We're here!" Naoto called over.

Tanjiro and Asuka looked forward to see several others sitting down by some tables. There were many new faces there.

"It looks like everyone is here." Yumi noted.

"Well, not everyone." Naoto said. "Ruby went to go get Heart, but I think they'll be here soon."

"We can at least start introductions." Yumi said. "Come on."

The people sitting at the table too notice of the ones arriving.

"Hey! What took so long?" Asked a boy with spiky blonde and black hair.

"It didn't take that much time." Naoto argued.

Asuka and Tanjiro were almost overwhelmed by how many people were there. A grey haired boy in a school uniform cleared his throat.

"I suppose introductions are in order." He said. "My name is Yu Narukami. Nice to meet you."

"My name is Asuka." Asuka said, bowing.

"Kamado! My name is Tanjiro Kamado!" Tanjiro said, bowing just like Asuka.

"No need to be so formal." Yu said, waving it off. "Everyone here is quite nice."

"I'm Hyde Kido. Nice to meet you." Said a the boy with blonde and black hair.

"Orie Ballardiae, a pleasure." Said a girl with long blue hair.

"Likewise, I'm Weiss Schnee." Was the voice from a girl with white hair tired in a ponytail.

"And I'm Yang Xiao Long!" Came the loud and boisterous voice from a blonde haired girl, before pointing behind her. "And last but not least..."

"I'm Naoto Shirogane." Said a voice. "Pleased to make your acquaintance."

"Eh?" Asuka said, looking at Yumi's boyfriend. "Two Naotos?"

Naoto (K) chuckled. "Yeah, we get that a lot. Just remember that I'm a guy and she's a girl, and you're good."

"W-Wait, a girl?!" Tanjiro said, stunned.

"If my appearance confused you, my apologies." Naoto (S) said. "I've just preferred this look for most of my life."

"I won't question it." Tanjiro said, respecting her privacy.

"Is Ruby still not here yet?" Naoto (K) asked, looking around.

"She sent me a text saying they'd be here in a few minutes." Weiss said, pulling out her scroll. "Actually, she should be here right now-"

"INCOMING!"

Everyone turned to see some... thing barreling down the road towards them.

"I-Is that a tank?!" Asuka shouted.

"A demon?" Tanjiro said, putting a hand to his sword.

The giant tank with a skull for a turret drifted to a stop right in front of the group.

"Thanks for the ride, Blitztank!"

Tanjiro and Asuka looked up to see two girls sitting on the back of the tank, before hopping off. The tank almost seemed to nod at them, before treading off.

"That was... something." Hyde said.

"Something indeed." Naoto (S) chimed in.

"Ooh Yumi, are these two your friends?" Said a peppy pink haired girl.

"Y-Yes they are." Yumi said, calming down from Blitztank's sudden appearance.

"Well, it's really nice to meet you two! I'm Heart Aino!" The pink haired girl said, spreading her arms.

"And I'm Ruby Rose!" Said an equally peppy girl with red and black hair and silver eyes.

"Took ya long enough sis." Yang said.

"Eh? You're sisters?" Tanjiro asked.

"Yup!" Yang said, pulling Ruby over. "The closest you can be!"

"Then I won't ask any more questions." Tanjiro said, smiling.

"So, what's your story, Tanjio?" Naoto (K) asked. "Yumi told us about Asuka, but never mentioned her having a boyfriend."

"Well, that's a recent development." Asuka said, blushing slightly and smiling.

"That, and Tanjiro's different." Yumi said. "He's not from our world, but rather, another."

"Another world?" Hyde said. "Like us?"

"Indeed." Yumi said, nodding.

Yumi then went on to explain the type of person Tanjiro was, as they all sat down at the tables. She told them how Tanjiro was a Demon Slayer, who was on a quest to turn his little sister back into a human.

Orie, Ruby, Weiss and Yang approved of his occupation, as Orie compared the Demon Slayers to the Licht Kreis while the others compared it to being hunters and huntresses. Yu and Yang both found Tanjiro's sibling devotion to be admirable, as they too had little sisters (well, little cousin in Yu's case) that they would protect with their lives.

Yumi then went into talking about Tanjiro's latest fight with Rui, where Asuka had supported him.

"-and then, despite being pushed to the absolute limit, Tanjiro got up, ready to keep fighting to protect Asuka and Nezuko." She said. "And that inspired Asuka to fight harder two and use her true power, letting the two of them defeat Rui."

They were all amazed at the feat the two had pulled off. Yumi hadn't explained yet that Rui actually wasn't defeated then, but she didn't get a chance to speak up before Yang chimed in.

"That's... awesome." Yang said with a smile. "And the sucker thought he was stringing them along?"

Everyone groaned at that.

"God dammit, Yang." Naoto (K) said, putting a hand on his face.

When Yumi told them how Tanjiro and Asuka met, they were all surprised. The fact that the two of them had met through their dreams. They didn't even think it was possible, but Heart was super ecstatic about it, saying how even dreams could be influenced by the power of love. System chimed in, saying that they went through their database, saying that the circumstance of Asuka and Tanjiro's meeting is completely unique, and is unheard of throughout the many worlds in the multiverse.

Everyone was amazed at it, and most of the girls found it quite sweet how the two had found true love in their dreams. Some of the guys found it a bit weird, but accepted it since, well, they were all from alternate worlds. How was this of all things too weird?

"But what are all of your powers?" Tanjiro asked. "Yumi told me and Asuka all about them, but it was still kind of confusing."

Yu smiled. "We'll gladly show you."

Yu held up a hand, while Naoto pulled out her pistol. Tanjiro watched in awe as mystical cards appeared before them.

"Izanagi!"

"Sukuna - Hikona!"

Yu smashed his in his hand, while Naoto shot her card. There was a burst of blue flames before them, before spiritual guardians manifested behind them.

"These are our Personas." Yu said. "Our true selves."

"Though senpai can use more than just one." Naoto noted, putting her weapon away.

"Incredible..." Tanjiro said, as they faded away.

Hyde and Orie were up next. Hyde pulled Insulator out of his hand, while Orie summoned Thanatos alongside here.

"So these are the EXS..." Asuka said. "They're both so different. Orie's is like a Persona."

"Wait, where do you keep your sword?" Tanjiro asked, looking at Hyde's hand.

"I... actually don't know." Hyde admitted.

The rest of the girls showed off as well. Ruby with her super speed, Weiss with her glyphs, and Yang with her golden aura. After they showed off their semblances, Heart raised her fist to show off some pink energy. The power of Partinias, the Arcana of Love.

"Well, we need to meet up with some of our other friends. We need to explore this place more." Yu said, looking at his watch. "It was nice talking to you two."

"Likewise." Asuka said.

Everyone waved goodbye, leaving Tanjiro, Asuka, Yumi and Naoto (K).

"Umm... what do we do now?" Tanjiro asked.

"Hey, you two wanna hang out with us?" Naoto asked. "Maybe like a double date or something?"

"That sounds lovely." Yumi said. "Are you two alright with it?"

"Well, yes, but..." Tanjiro stuttered, blushing.

"This would be our first date." Asuka said, equally red.

"Oh..." Naoto and Yumi said in unison.

"I... don't really know how a date works." Tanjiro said, rubbing the back of his head.

"Well, I do have dating experience." Naoto said. "I can lead the way, I guess."

Acting as the unofficial leader of the group date, Naoto led the group around. Tanjiro was still amazed by all the advancements the world had, the technology being far more advanced than what he had back home. Every now and then they would bump into someone familiar and there would be a short introduction or two before the double date continued.

Asuka couldn't help but find Tanjiro's reactions to everyday conveniences to be both funny and adorable. When the group brought crêpes, the face Tanjiro made when biting into it was priceless, as he had never tasted something as delicious as that before.

They eventually went to an arcade, where Naoto decided to teach Tanjiro about video games. It wouldn't really be of help to him in his world, but he might as well help Tanjiro enjoy himself.

Asuka and Yumi sat down on a bench nearby, as Tanjiro and Naoto were at a crane game.

"Alright Tanjiro. Let the master teach ya how to do this." He said, inserting a coin into the machine.

Tanjiro nodded, looking closely.

"You take the joystick here. Move it above the one you want and then..."

Naoto hit the big red button next to it. The crane drooped down and grabbed a small teddy bear, which it then carried to the exit.

"And that's how you do it." Naoto said, holding up the stuffed animal.

"Amazing!" Tanjiro said, with stars in his eyes. "Allow me to try!"

"Alright buddy." Naoto flipped him a coin.

Yumi and Asuka watched as Tanjiro got ready to play.

"They're getting along quite well, don't you think?" Yumi said. "I'm glad."

"I can see how you fell in love with Naoto." Asuka said. "He's very kind."

"Same for your Tanjiro." Yumi said. "Imagine if our roles were swapped?"

The two laughed at the idea of having swapped romantic partners.

"Hey, do you think maybe the others might want to meet your alternate world friends too?" Asuka suggested. "If you could bring me and Tanjiro, I think they could come too."

"That sounds like a wonderful idea." Yumi agreed. "I can only hope it's possible."

The two turned back to the boys, before laughing again. This time, at Tanjiro failing the crane game.

"I will master this contraption!" Tanjiro declared, as the claw missed again. "Naoto, another coin please!"

"You're gonna wring me dry dude." Naoto said, giving him another one.

The day was soon over. While some of the others would stay longer, it was almost nighttime for Asuka, Yumi and Tanjiro. It was time for them to leave.

They walked back to the original courtyard, where they heard System waiting for them.

"I've analyzed this world during your visit." She said. "The world is perfectly stable, meaning that you can come back anytime."

"Well that's pretty sweet." Naoto said. "Alright!"

"And furthermore. This world acts like a crossroads too. This means that you will be able to visit eachother's worlds as well."

"Even more sweet." Naoto said. "I guess that means..."

Yumi smiled, hugging the teddy bear that Naoto had won earlier. "Our relationship can continue."

"But what about me?" Tanjiro asked. "I don't have a keystone or anything. I can't bring any of my friends along..."

"I have a solution for that." System said. "Tanjiro, hold out your hand."

He nodded, and did so. Forming in his palm was a keystone not unlike Yumi's. This one was pure black, like his sword.

"With that keystone, you can visit the midworld anytime you wish, without having to contact Asuka or Yumi first." She said.

"Really? Thank you so much!" He said, bowing... even though there was nothing in particular to bow to. He looked at the keystone in his hand. He could bring Nezuko, Zenitsu and Inosuke here too. He couldn't wait.

"Well, I suppose it's time for us to go." Asuka said.

She and Tanjiro briefly hugged, as did Yumi and Naoto. They separated, before Yumi and Asuka glew with white light, while Tanjiro glew with black light.

Naoto waved to them and said goodbye, as they all disappeared, going back to their own world.

With them all gone, Naoto stretched a bit, before putting a hand on his neck.

"Man. I can already tell that things are gonna be hectic now." He said. "But... it'll probably be even more fun too."