— — — — — —
High above the sky, a lone figure drifted upward toward the crown of the World Tree.
"That was way too close!" Rimuru let out a relieved sigh. "Good thing I reacted fast, or I wouldn't have lived to see tomorrow's sunrise." He patted his chest dramatically, still shaken.
"But now that I think about it…" He allowed a sly smile to curl his lips. "I wonder if this little idea of mine will actually work." With that, he shot upward faster.
Before long, he reached the very top.
"Wow, that's high." Rimuru leaned forward, peering down at the sprawling city far below. "This tree is ridiculously huge. Honestly, it's like a whole forest by itself. The Gacha has many good things for real."
Folding away his wings, he set foot on the leafy canopy.
"Alright. I hope it goes well. Time to get started."
He pressed his palms together, letting energy swirl between them. Slowly, a perfect cube of shimmering space-energy formed in his hands.
"Open!"
The cube exploded outward, releasing a veil of glowing blue light. It spread, wrapping around the treetop.
In moments, the entire crown of the tree was enclosed.
Rimuru poured his strength into the space itself. Like a balloon being inflated, the inner world stretched larger and larger, though from the outside the light barrier remained unchanged.
Dozens of times bigger. Hundreds. Thousands. Soon it rivaled the size of the Great Jura Forest itself, and still it kept expanding.
"Perfect." Rimuru clapped his hands in satisfaction. "Looks like my idea worked. They're in for a huge surprise."
Whistling a tune, he happily flew back.
"Master!" Ranga bounded toward him, tail wagging as he caught Rimuru's scent.
"Good boy, Ranga." Rimuru rubbed his head affectionately and bounced along, humming.
Ranga tilted his head. "Master seems really happy…" He watched Rimuru's skipping figure with confusion, then trotted after him.
---
The next morning, before dawn had even fully broken, Rimuru was already awake. He sent word to all guild members to gather for the construction project.
"Why so early?" Shion grumbled, rubbing sleep from her eyes. "If I don't sleep well, it ruins my skin, you know."
"Maybe it's urgent," Benimaru muttered, also squinting blearily but forcing himself awake.
"Zuuuuh…Gorororo."
That was Garp—yes, snoring while standing upright.
"He'd better have a good reason for this," Whitebeard growled. He was not a morning person.
Roger nodded.
As everyone mumbled complaints, Rimuru strolled out, beaming with excitement.
"Looks like everyone's here. Great job showing up on time." He scanned the gathered crowd with satisfaction.
"So, Lord Rimuru," Shion asked with suspicion, "why did you call us out at this hour?"
"Didn't I tell you?" Rimuru tilted his head innocently. "We're going to build the guild today."
"You told us that?" Everyone shouted in unison, veins popping.
"…Maybe I forgot?" Rimuru's smile faltered under their glares.
"So that's it? You dragged us out here just for this?" Whitebeard's fists tightened, glowing faintly with quake energy. "I didn't sleep because of this?"
"It's kinda rude." Roger wanted to draw his sword.
"Rimuru-sama. Please excuse my rudeness," Shion said sweetly, hefting a giant blade onto her shoulder.
"Zzzzzzz…Gorororo." Yes, Garp was still asleep.
"Well… it's morning already! Early to bed and early to rise makes you healthy!" Rimuru laughed nervously.
Shuna's voice was ice-cold. "It's four thirty in the morning."
"..."
---
After thoroughly scolding him, the group reluctantly calmed down and followed Rimuru to the top of the World Tree.
"What's that?" Shuna stared at the enormous blue barrier glowing before them.
"Hehehe." Rimuru snapped his fingers proudly. "Come inside and see."
Inside the barrier, everyone froze in shock.
"Incredible…" Whitebeard muttered. From the outside, the crown hadn't seemed so large. But inside was an entire world, vast enough to rival a god's creation.
"So this is the surprise?" Shion's eyes widened in amazement.
"That's right," Rimuru declared smugly. "I made a pocket world, about the same size as the Jura Forest. Pretty impressive, huh?"
"Truly worthy of Rimuru-sama," Diablo said with admiration. Destroying worlds, they could all manage. Creating one? That was something else entirely.
"Alright then," Rimuru said, striking a pose. "Let's get to work on the guild!"
"Yeah!"
The members sprang into action. Some gathered resources, others started construction. At first it was chaos, but soon teamwork kicked in and progress accelerated.
At the center, everyone joined forces to raise a massive guild hall. But when Rimuru saw the finished product, he nearly died of embarrassment.
It was a colossal blue slime. A giant Rimuru-shaped building.
He was so mortified that his slime form was about to turn pink.
...
Elsewhere, Whitebeard and his crew built a house shaped like a giant ship, modeled after the Moby Dick.
Sengoku's group recreated a miniature version of the Marine Headquarters.
The local demon lords… well, Guy Crimson and the other Primordials built nothing but giant stone pillars and called them "houses."
And his other subordinates? Multiple different-colored slime houses.
Did no one think about Rimuru's feelings? Mortifying didn't even begin to cover it.
Milim, meanwhile, didn't build anything at all. She just claimed a room in Rimuru's "slime house," declaring she wanted to live close to her bestie.
The truth? She was just lazy.
At least most of these creations were still functional.
But Ramiris… oh, Ramiris. On the outside, her house looked normal. Inside? A sprawling labyrinth with no exit. A "home" that instantly lost all house privileges.
The good part was that everyone enjoyed building the guild, knowing there would be many more worlds to explore later.
---
After a while, a strange voice echoed.
"Uh… hello? Where am I? This doesn't feel like Hogwarts anymore."
.
.
.