"Ren, you're here too?! That's great! I was actually planning to go to the Kingdom of Falmuth to find you. With something this fun going on, how could I forget my best buddy?"
"Now that you're here, this labyrinth officially becomes a joint project built by the five of us! Someday it'll definitely become famous across the whole world! Hahahahaha!"
The moment Ren Kuroda appeared, the one who reacted most enthusiastically was Milim.
Ever since the Sky Queen, Frey, had become her subordinate, Milim had completely turned into a hands-off ruler. She practically lived at Rimuru's place now, rarely ever returning to her own territory.
After all, everything in Rimuru's domain felt fresh and exciting to her. And most importantly—she never had to worry about being bored.
As for the "five people" Milim mentioned, they were simply: herself, Ramiris, Veldora, Rimuru, and now Ren.
In the past, Ramiris's residence had technically been called a labyrinth as well.
But honestly, it was just… a labyrinth.
The monsters guarding it were embarrassingly weak—and there had only been one of them.
For someone who held the title of Demon Lord, Ramiris had been so poor it was almost tragic.
This time, however, things were different.
After learning that Ramiris intended to settle down permanently in the Jura Forest, Rimuru discovered something interesting: Ramiris possessed the natural ability to easily construct underground labyrinths.
And that was when Rimuru suddenly came up with a bold idea.
He wanted to create a massive, multi-layer underground labyrinth open to both humans and monsters.
From the upper floors down to the deepest levels, the labyrinth would contain monsters of increasing difficulty, each floor guarded by progressively stronger bosses.
Adventurers entering the dungeon could challenge deeper and deeper layers according to their own strength—until eventually confronting the Demon Lord who ruled the labyrinth itself.
By the time Ren arrived, the underground labyrinth was already nearly complete.
Most of the monsters populating its floors had been gathered by Veldora and Milim from various parts of the world.
As for the final boss guarding the deepest floor…
That role had naturally been claimed by Veldora.
Rimuru had even prepared a grand treasure hoard for the final chamber.
Being able to serve as the ultimate boss of a dungeon thrilled the chuunibyou dragon to no end.
Veldora was extremely satisfied with his new job.
"Treasure… dragons… dungeon exploration…" Ren muttered while rubbing his chin.
"This is basically turning into an RPG."
"Well… for this world, a facility like this would definitely be something completely new. Honestly, it sounds like it could work."
Just from Milim's excited explanation, Ren immediately understood what Rimuru was trying to do.
After all, he also came from modern Earth.
"Yeah! Yeah! That's it! That thing Rimuru said—RG something!"
Milim nodded energetically.
"As expected of my best friend! You figured it out right away!"
"It's RPG," Rimuru corrected with a sigh. "Role-Playing Game."
"The people challenging the labyrinth are the heroes, while Ramiris and Veldora act as the Demon Lords."
Rimuru then turned to Ren.
"What do you think? If we charge a small entrance fee to challengers while developing the labyrinth… do you think people would come?"
Even though Raphael, Lord of Wisdom was incredibly powerful when it came to analyzing and processing data, it obviously wasn't omnipotent.
It couldn't teach Rimuru how to run a country.
And in his previous life, Rimuru had only been a regular office worker.
This entire dungeon project was basically just a spur-of-the-moment idea.
Ren stared thoughtfully at the labyrinth entrance before speaking.
"…Mind if I try clearing it as the first challenger?"
"If I don't experience it myself, I won't be able to give you any meaningful feedback."
He was genuinely curious how far Rimuru and the others had taken the concept.
"You can, sure," Rimuru replied.
"But the monsters on the lower floors are pretty rare, so don't go overboard."
"With your strength, you could definitely blast your way through the entire labyrinth."
"Veldora and Milim spent days catching some of those creatures."
Half an hour later, Ren returned to the surface.
Yes.
Only thirty minutes had passed.
The labyrinth had one hundred floors.
And Ren had cleared every single one of them in half an hour.
Most of that time had actually been spent walking.
After all, the labyrinth had been designed with adventurers of different skill levels in mind.
The first five floors contained no monsters at all—only complex maze-like terrain.
Ironically, this simplest challenge for ordinary people had been what slowed Ren down the most.
Starting from the sixth floor, low-level monsters began appearing.
Their strength was extremely weak—roughly equivalent to the classic fantasy trio: skeletons, slimes, and goblins.
Interestingly, these monsters hadn't been captured by Milim or Veldora.
They had formed naturally.
Because Veldora possessed an enormous amount of magicules, the excess energy leaking from his body constantly generated weak monsters in the surrounding environment.
Most of these creatures lacked intelligence.
As long as Veldora remained as a massive magicule source, new low-level monsters would continue spawning endlessly.
The labyrinth contained one hundred floors, and every ten floors Rimuru had placed a mini-boss, just like in an RPG.
The bosses gradually increased in strength the deeper one went.
During his run through the dungeon, Ren even spotted several familiar figures.
Among them were former subordinates of the late Demon Lord Clayman.
There was Adalman, the undead priest who had once guarded Clayman's territory.
Then the Death Knight Albert.
And one of Clayman's former Ten Great Fingers—the fox-like nine-tailed creature known as Kumara.
Further down, Ren encountered members of the Insectar race from the Jura Forest.
After receiving names from Rimuru, both the Insect King and Insect Queen had evolved into powerful monsters and now served as floor guardians.
But the most outrageous part was waiting near the very bottom.
The guardians of floors 96 to 99 were four dragons representing the elements:
Fire, Ice, Lightning, and Earth.
Not drakes.
Not pseudo-dragons.
Actual true dragons of the lower dragon species.
They weren't primordial dragon types like Veldora or the legendary Star King Dragon, but natural dragons born from environmental magic.
Even so, each of them possessed power comparable to the former Demon Lord Clayman.
In terms of magicule reserves, they were essentially Demon Lord–class monsters.
Milim had personally gone through enormous effort to capture them from across the world.
At first, the four dragons had fiercely resisted.
As members of the proud dragon race, they absolutely refused to work under others as mere employees.
But after Milim gave them a thorough lesson in "persuasion through virtue"—
The dragons obediently allowed themselves to be dragged into the labyrinth.
However, once they actually arrived…
They discovered the environment was far better than expected.
Because Ramiris could freely shape the labyrinth's terrain, she customized floors 96 to 99 into environments perfectly suited to each dragon's element—icy tundras, blazing volcanic fields, and more.
And since Veldora guarded the 100th floor, the closer one got to him, the denser the magicule concentration became.
The four dragons' floors were practically right next to the Storm Dragon himself.
Comfortable habitats.
Extremely dense magicules in the air.
For dragons, it was basically paradise.
After experiencing this luxurious living arrangement, the four elemental dragons immediately changed their stance.
As long as food and housing were provided…
Working as dungeon bosses?
No problem at all!