Suddenly, but if you head west from the wetlands where Lizardmen inhabit, you'll reach a mountainous region.
The Great Underground Cavern is a natural labyrinth born from an active volcano. Its structure is so endlessly convoluted that even the Lizardmen themselves haven't mapped all of it.
Venture deep into one passage and you'll find yourself in an ice cave world; take another route far enough and you'll emerge into a scorching realm of magma pools.
It's said that a demonic domain deemed too dangerous for entry is hidden within.
But this time, the focus isn't on the labyrinth.
It's on the active volcano itself.
If there's a volcano, shouldn't there be hot springs too? — That was how it all began.
◇◇◇ "So, everyone! I'm thinking we should go to a hot spring. What do you say?"
My voice echoed through the conference room.
But apparently, my plan didn't come across well to the others.
"I mean, sure, but a hot spring is just hot water, right? Can't we just bathe in the river?"
"Yeah, exactly. In the Dwarf Kingdom, they had hot spring water piped into the bathhouses, but it's really nothing that special."
It seemed hot springs weren't anything novel to them, and I could understand their perspective. But what I had in mind and what the dwarves were imagining were completely different things.
"A hot spring, you say? What exactly is that?"
"I believe it's a place where hot water, warmed by volcanic heat, wells up and collects?"
By thoroughly practicing proper hygiene through bathing, you could also prevent illness. More importantly, as a former Japanese person, I fully intended to champion bathing culture. That it was something I personally enjoyed the most went without saying.
"Exactly right! Well, there are hot springs unrelated to volcanoes, but let's set those aside. The volcanic hot springs Souei just described are our destination this time. During the process of underground water being heated, all sorts of minerals dissolve into it, making it incredibly beneficial for the body. You could say it's the perfect remedy for bodies exhausted from battle!"
My impassioned explanation piqued Benimaru's interest.
"That does sound good. Trying it out could be fun."
"As expected of Lord Rimuru, you're quite knowledgeable."
It looked like they were coming around to my plan.
Now came the convincing of the old dwarf guys — "And another thing — just imagine it. When you bathe in a river, do you go in fully dressed? I mean, if you're just splashing water with a bucket you don't need to strip down, but in a bath, taking off your clothes is natural!"
"Well, yeah, that's true, but..."
"We're perfectly happy with just a river bath, right?"
"............"
Good grief, these stubborn old guys.
"Irrelevant, all of you. Let your imaginations run a little wilder. For instance —"
"Oh!?"
Before I could elaborate, Kaijin seemed to have caught on to something.
"...No way! Boss, you're —"
Following Kaijin's lead, Garum finally grasped what I was getting at as well.
"Heh heh heh, I see you've figured it out. That's right, gentlemen. A paradise awaits you there — wouldn't you agree?"
At my words, everyone swallowed hard.
The half-hearted attitudes from moments ago had vanished entirely, and passion burned in every pair of eyes.
"Furthermore, hot springs have this wonderful custom called 'mixed bathing' —"
"Boss, I'm in."
"Need you even ask? We're comrades!"
"Mm. So it is."
"............!!"
The dwarves pledged their enthusiastic cooperation.
Benimaru was somewhat less keen, and Souei wore his usual "this doesn't concern me" expression.
And so, the plan to bring hot springs to the Monster Nation was set into motion.
◇◇◇ Why not just build a bathhouse, you ask?
Well, it wasn't that I couldn't. The reason I didn't go with a bathhouse was simple: it would cost too much.
Heating a bathhouse required enormous quantities of firewood. Right now, construction was in a frenzy and we could repurpose scrap lumber, but it was unwise to assume that would last forever. Even gathering branches from the forest, we already used fire for cooking — there'd be nothing left over to heat a bath.
After surveying the site, I discovered a hot spring source at the perfect temperature for bathing.
From there, it was my turn. I crafted pipes from
The work took place within shadow space, but since I didn't need to breathe, it posed no problem at all. The only real challenge was figuring out how to disguise the pipes emerging from the shadow space — and even that, I left entirely to the Great Sage, so it was resolved without any fuss on my part.
The dwarves carved out marble and built a magnificent bathhouse. The mention of "mixed bathing" had clearly done the trick — their enthusiasm was palpable. One glance and you could feel the air of luxury; it was a truly lavish construction.
This hot spring would later become a tourist attraction and spread throughout the world, but that's another story.
Huh, what happened to the mixed bathing, you ask?
In this world, nothing that good could possibly be that simple.
"My, what a wonderful result. As expected of dwarven craftsmanship.
Not only do we need a women's section, but you'll have to prepare a men's one too, you know."
When
Benimaru, apparently content so long as hot springs existed at all, consoled the dwarves. At least they wouldn't be discouraged and would keep working hard on the men's bath. Everything was going according to plan.
Incidentally, being a slime, I could go in the women's section whenever I wanted — but that was none of their business.