When Makoto returned home, he found Shiki sitting comfortably, going over reports spread out before him, while talking with Riku—who sat across from Shiki, also looking at the reports in his hands—and Shuvi, who was preparing tea.
"Welcome back, Waka-sama," said Shiki.
"Waka-sama," Riku and Shuvi said, bowing to Makoto.
"I'm back," Makoto said.
"So, how did it go, Waka-sama? Did you manage to bring the item back?" Shiki asked him.
"Of course I succeeded in bringing it back," Makoto replied, pulling out a transparent case that revealed an object resembling a short spear.
"I don't sense any aura coming from this thing," Riku remarked.
"That's not true, Riku. From what I can tell, we can't sense anything because the case is sealing away all the aura and energy of the object inside it," Shuvi corrected.
"Shuvi is right. This case is made of dimension walls, which have the property of repelling energy," Makoto explained.
"But Waka-sama, aren't dimension walls unable to fully isolate the energy within them? After all, that's how you were able to detect other worlds out there," Shiki pointed out.
"That's true if you only use ordinary dimension walls—they wouldn't be enough to fully isolate this object. Which is why I used a little trick when I made this case," Makoto said.
"A trick? What kind of trick, Waka-sama?" Shuvi asked curiously.
"It's simple really. All I did was compress the dimension walls and make them extremely dense," Makoto answered.
"EHHH!?" Shiki exclaimed in shock, while Riku and Shuvi just looked confused.
"Um… why are you so surprised, Shiki?" Riku asked, bewildered.
"Of course I'm surprised! Riku, you have no idea how absurd what Waka-sama just did is! Let me explain—from all my research, a dimension wall is a membrane that separates a world's dimension from the void of chaos. It's a very unique, flexible, and remarkably sturdy membrane," Shiki explained.
"So what's so strange about it?" Shuvi asked, still puzzled.
"I've tried compressing samples of dimension walls myself, you know. But every time I tried, the wall would crack and shatter into pieces instantly! I still haven't figured out why the samples broke," Shiki said.
"Ah, that's because you were studying them the wrong way, Shiki. A dimension wall exists as a single, complete whole. Examining just a portion or a sample might be enough for basic observations, but if you want to understand it fully, you have to study it as a whole," Makoto told him.
"I see… So that's why every one of my experiments failed. You have to look at the whole picture, not just an incomplete sample," Shiki muttered, sinking into deep thought.
"Helloooo~ Shiki, snap out of it!" Makoto called out, waving his hand in front of Shiki's face.
"Ah—my apologies, Waka-sama! It seems I got lost in my own thoughts again," Shiki said, bowing apologetically.
"It's quite alright. Now, where were we?" Makoto asked.
"You were about to explain this spear-like object, Makoto-sama," Shuvi reminded him.
"Oh, right. This item is quite fascinating," Makoto said.
"Does it serve some special purpose, Makoto-sama?" Riku asked.
"This object is a fragment of a spear that was destroyed long ago. While the materials used to make it are ordinary, this spear could store a unique energy capable of corrupting anyone below the rank of a god," Makoto explained.
"Is this energy truly that dangerous, Makoto-sama?" Shuvi asked, concerned.
"It is. Ordinary beings without special protection would be unable to resist its corruption—it would drive them mad, and they would attack anyone in their path," Makoto replied.
"Any idea where this thing came from, Makoto-sama?" Riku asked.
"Not yet. We'll need to investigate it further," Makoto told them.
"Understood, Waka-sama. Riku and I will draw up a plan to deal with this as soon as possible," Shiki said. With that, the three of them left Makoto's residence.
"Haah… I never expected something like this to come up," Makoto sighed, gazing at the mysterious object still radiating dangerous energy.
"For now, all I can do is wait for Shiki and Riku's report. First things first—I need to write an interdimensional invitation. Nueria, please create an interdimensional invitation for Rimuru as a test run," Makoto said.
[Response: Understood, Master. Beginning creation process… 1%… 10%… 30%… 50%… 80%… 100% — Process complete.]
At Nueria's words, an elegant golden invitation adorned with the World Tree emblem materialized before Makoto.
"Ooh, this is even nicer than I imagined," Makoto said, holding it up.
"Hmm… what should I write? Since it's for Rimuru, I'll keep it simple," he thought to himself, and began to write.
"Alright, it's done. Time to send it on its way," Makoto said. He easily opened a portal leading to Rimuru's world and tossed the letter through.
"Now we just wait for Rimuru to arrive," he said casually.
After being sent, the letter traveled for several days toward Rimuru's world, passing effortlessly through that world's dimension wall.
Meanwhile, Rimuru was discussing dungeon construction with Ramiris when they both suddenly stopped—surprised to see a letter appear out of thin air right in front of them.
"Rimuru! Did you see that? That letter just appeared out of nowhere!" Ramiris exclaimed.
"I saw it. It suddenly showed up right in front of my face," Rimuru replied.
Raphael, can you detect where this came from? Rimuru asked in his mind.
[Response: The letter's origin is unknown.]
Do you detect any danger from it?
[Response: All readings indicate this is an ordinary letter.]
"Alright, let's open it," Rimuru said, reaching for the letter. Though still wary of something appearing so abruptly, he trusted Raphael's judgment.
"Wait! Isn't that dangerous, Rimuru?" Ramiris asked anxiously.
"Relax. No danger detected," Rimuru assured her.
"Let's see what it says," Rimuru said, and opened the letter.
Hello Rimuru! How are you doing? Hope you're doing well!
Sorry for the surprise—this letter is a prototype interdimensional invitation I made specially, so you can come visit my world and hang out! It's really easy to use: just tear this invitation, and a portal leading to my world will open for a short time. Since it uses my portal, you can bring as many people as you like. Don't forget to bring Milim along—I'd hate to have her pout because she wasn't invited.
Best regards,
Misumi Makoto
"Ooh! It's from Makoto!" Rimuru said, eyes lighting up.
"Makoto? Who's that?" Ramiris asked.
"A friend of mine from another world," Rimuru replied.
"Another world!? Like in the comics I read!?" Ramiris asked excitedly.
"Umm… I'm not sure. I've never been there myself," Rimuru said.
"So what does it say? What's it about?" Ramiris pressed.
"It's an invitation—to come play in Makoto's world!" Rimuru said.
"Can I come too!?" Ramiris asked instantly the moment she heard the word "play."
"Hmm… I don't see why not. He did say to bring Milim as well," Rimuru said.
"YATTA~! 🎉" Ramiris cheered.
"Alright then—before things get too busy, let's take a little trip," Rimuru declared.
"YAY~!" Ramiris beamed.
And so, Rimuru and his companions began making plans for their journey to the world of Erindal. Without hesitation, Rimuru contacted Milim and explained the invitation. Milim was overjoyed—so much so that Frey, who was attending her, could barely keep up and simply followed along, leaving Carrion to watch over their territory.
A few days later, the whole group gathered: Rimuru, Milim, Ramiris, Veldora, Frey, Shion, Shuna, Ranga, Hakurou, Gobta, Beretta, and Treyni. The others couldn't come, as they had duties to attend to.
"Everyone! Are you all ready!?" Rimuru called out.
"YES~!" they all shouted enthusiastically.
"Alright then—let's go!" Rimuru said. He tore the invitation in his hand, and instantly a portal opened before them. Without a moment's hesitation, they all stepped through. Once everyone had crossed, the portal closed behind them.
At that same moment, in the center of Origin City, a portal appeared in the main square—and out stepped Rimuru and his party.
"Looks like the city Makoto built is even more impressive than I imagined…"
"Woah! This city is gorgeous!" Ramiris marveled, looking around in awe.
"I can feel so many powerful people here," Veldora remarked.
"I smell something delicious!" Milim's eyes lit up.
The group looked around in wonder, and before long, Makoto appeared before them.
"Yo, everyone! Welcome to Origin City!" Makoto greeted them with a wave.
"Hey Makoto! Long time no see!" Rimuru smiled.
"Long time no see~!" Milim chimed in cheerfully.
"Good to see you both, Rimuru, Milim," Makoto said, then greeted each person in turn.
"Come on, let's head to my place first. Mio's prepared snacks and tea for you all—and after that, you're free to go exploring the city!"