Because Reinhardt had to step away for business, our afternoon training was left to the four of us: Lady Elia, the Madam, Reinbach-sama, and me.
"Goodness, my father is always like this the moment work is involved," Elia sighed.
"It really is a problem, isn't it? Leaving his daughter and Ryoma-kun behind like that. Don’t you agree?" Elize added.
"Well, I’m partly the cause of it, so I can’t really complain... Besides, Reinhardt-san is just dedicated to his work. That’s better than him being lazy, isn't it?"
"I suppose that’s true... Ah, we’ve arrived. It’s here."
Guided by the two adults, we arrived at the entrance of a relatively large mine shaft.
"Now then, from this point on, I want the two of you to take the lead. My father-in-law and I will follow behind. We’ll step in if things get dangerous, but otherwise, you won't be getting any help from us."
"This is for Elia to gain experience, and Ryoma-kun is already quite seasoned himself. I’m sorry, Ryoma-kun, but I’d like you to refrain from offering too much advice as well, if you would?"
The challenge was laid down before us without warning.
"I will do my best," Elia said firmly.
"Understood."
Seeing how Elia obeyed without a hint of hesitation, she seemed used to these sudden assignments from her family. She stepped into the shaft without delay. This tunnel was wider than the one we had explored this morning, and the walls were covered in moss in several places. It looked like it might be slippery if I wasn't careful where I stepped. I made a mental note to stay alert.
"It’s so dark that I can’t see very far ahead," Elia murmured.
I’d noticed this during the morning session as well, but unlike me—who was accustomed to the dark from hunting at night—the young lady’s vision was quite limited in this environment.
"Ryoma-san, how did you handle hunting at night? Did you use Light magic?"
"If it didn't matter if the target noticed me, then yes. For example, when attacking bandits. But if you want to move without being detected, it's better to use the neutral magic, Detection. There’s a chance they might sense your mana, but it’s still harder to spot than a Light spell."
"I’ve never been able to use Detection very well. How do you do it, Ryoma-san? I was taught to 'spread my awareness,' but I never really understood what that meant."
Detection, huh...
After a moment of thought, I used Earth Magic to create a stone bowl and Water Magic to fill it.
"Please, look at this."
"?"
I showed her the bowl and dropped a small stone into the center. Naturally, ripples spread across the water's surface.
"Think of the stone in the center as yourself and the ripples as the flow of your mana. You spread your mana out in waves from your position to cover the area you want to search. Now, if a monster is there..."
I placed several more small stones in the bowl, calmed the water with magic, and then dropped the center stone again. The ripples formed once more, but this time, the waves were interrupted by the other stones.
"See how the waves hit the stones and break? If you think of that as the reaction you get when a monster or a person is caught in your Detection, it might be easier to visualize."
"I see! That’s much easier to understand than the explanation I received before. Let me try... Detection!"
The moment Elia activated the spell, a massive surge of mana scattered from her into the surroundings. It was an overflowing tidal wave of mana, unlike anything I had ever felt from anyone but myself.
Even without trying to concentrate, I could feel the sheer pressure of her magic. It was, in a word, incredible. But at this level, any enemy mage would notice her instantly.
Sensing the mana within one's own body through Mana Perception is the absolute fundamental of magic. Regardless of talent, there is no such thing as a mage who cannot perceive mana.
"There are many things just a little further ahead!" she exclaimed.
"That was a success. However, you put a bit too much mana into it. If there was a mage nearby, there’s a high probability you would have been discovered."
"I-is that so? I suppose I need more practice."
"I’ll take over Detection duties while serving as the vanguard. Please focus on your magic just as you did this morning, My Lady."
"Understood. I’m counting on you, Ryoma-san."
With the task entrusted to me, I used my own Detection. She was right; there were a large number of creatures ahead. However, they seemed to be a gathering of very small monsters.
"Further ahead, the path opens into a large cavern. There's something filling the entire ceiling. Since they're up there, I assume they're Cave Bats?"
"If they're on the ceiling, they likely are," Reinbach confirmed.
"If they’re filling the entire room, that might be a bit much for Elia, don't you think?" Elize asked.
"Indeed. If it were one or two, it would be good practice for her aim, but with a swarm like that, you’d hit something no matter where you fired."
Cave Bats were roughly the size of an adult’s palm—monsters that fed primarily on insects. Their ecology was virtually identical to the bats on Earth. They had almost no way to attack and were weak enough for a child to defeat, but because they flew around so much, they were difficult to hit, earning them a Rank F classification. Dealing with a whole swarm sounded like a nuisance. Neither of the adults seemed particularly eager to deal with them either.
"In that case, may I try an experiment?"
"An experiment?" they asked in unison.
"Yes. If it goes well, I might be able to wipe out the Cave Bats all at once."
I double-checked what I knew of Cave Bat biology and confirmed they were indeed just like the bats from my old world. If so, my best weapon was "sound." I figured that if I hammered the cavern with a massive noise via magic, I could knock them all unconscious.
In my previous life, we had non-lethal weapons like stun grenades. I could replicate that effect with magic.
I had spent time in the forest researching sound-related magic. There was Silent, which suppressed air vibrations to erase sound; Big Voice, which amplified vibrations; Voice Change, which could make you sound like you’d inhaled helium; and Whisper, which delivered sound to a specific spot within sight. Then there was Sound Bomb, a combination of Big Voice and Whisper.
I had originally developed Sound Bomb for exactly this kind of situation. When I tested it on a Black Bear, it ruptured the creature's eardrums and knocked it out cold with one hit. As long as I didn't mess up the execution, it should work on bats. Though, I hadn't used these spells much lately—ever since I’d spent hours talking to myself indoors to practice Whisper and realized how pathetic I looked, I’d stayed away from them.
The only concerns were whether the noise would cause a cave-in, whether other people were nearby, and what to do if I failed to finish them off.
"You needn't worry about the tunnel," Reinbach assured me. "This shaft has been reinforced with Earth Magic to prevent collapses. As for other people, you can check with your Detection. And if you fail to finish them..."
"...Should I leave the rest to the slimes?"
"That sounds like a plan. If that fails, we'll step in."
With the plan settled, I summoned a Big Sticky Slime from my Dimension Home.
"I'm counting on you."
I had the slime block the tunnel with its massive body. I crept forward just enough not to startle the bats and signaled the slime to stretch its body into a mesh. It obeyed perfectly, creating a sticky net across the tunnel. Finally, I cast a Soundproof Barrier using Barrier Magic, wrapping it from the front of the slime net all the way back to the Madam at the rear to ensure no sound leaked inside.
"Preparations are complete."
"Any time you're ready."
"Then... Sound Bomb."
In that instant, a tremendous explosion must have thundered through the cavern on the other side of the barrier. Even though I couldn't hear it, I saw a rain of shadows falling from the ceiling.
"It looks like a success. Let’s go."
I dispelled the barrier and pushed forward with the slime net as a shield. The ground was carpeted with an immense number of Cave Bats. Most had been knocked unconscious before they could even twitch, and of those that remained conscious, fewer than ten were able to take flight. Even those few flew unsteadily, crashing into the walls and falling back down. A couple managed to flutter toward us, but they were immediately caught in the Sticky Slime’s net.
"My word, this is..."
"You really defeated them all with a single spell."
"That was amazing, Ryoma-san!"
"It’s been a while, but I'm glad it worked. Their sensitive hearing turned out to be their downfall. Oh, would it be alright if I let the slimes eat them?"
"They are the monsters you defeated, Ryoma-kun. Do as you wish."
"Besides, Cave Bats don't have any parts that fetch a price anyway," Elize added.
I commanded the Big Sticky Slime to separate, and a total of 364 Sticky Slimes set about devouring every last bat.
Oh, looks like several of the Sticky Slimes are ready to divide again. I’ll have to take care of that once we’re back at the inn.
For the next hour, we continued through the tunnels. I provided support and advice while the slimes helped as Elia used her magic to hunt the remaining monsters.
"Hey, Ryoma-kun!"
When we finished the second round of extermination and exited the shaft, Reinhardt was waiting at the entrance.
"Is something the matter?"
"It’s about the iron. I was hoping you could make some iron blocks for me to use as samples for the merchants and blacksmiths. If possible, could you shape them into rectangular ingots?"
"I can do that easily. Alchemy has a Deformation circle specifically for changing shapes. It’ll only take a moment."
"Really? Then I’d like to get started right away."
I swapped places with Reinhardt and began producing the ingots. He offered to help, but I told him I had it handled and sent him back to Elia’s side. It wasn't a job that required two people.
True to my word, the work was finished in a heartbeat. Most of the time was spent simply walking to the slag heap.
"Sebas-san, the ingots are finished."
"Indeed. I shall take custody of them. ...By the way, Ryoma-sama, what do you intend to do with the rest of your time?"
"Let’s see..."
With the ingots handed over at the square, my work was technically done. I considered going back to monster hunting, but Elia and the others were already deep inside the mine.
Should I go into another shaft alone? Honestly, the monsters here were so weak they didn't offer much training value. Considering the time it would take to get back to town, it was an awkward gap... I suppose I’ll use the time to manage my slimes.
"Some of my slimes are about to divide, so I think I’ll handle the contracts and some training."
"In that case, please feel free to use that corner of the square. It’s open, and we’ll be within earshot if you need anything."
So, I spent the remaining time leisurely, letting the slimes divide and putting them through their paces.
One hour later.
The Jamil family returned to the corner of the square, which was now occupied by various groups of slimes separated by type.
"Ryoma-san!"
"Ah, My Lady. Is the training finished?"
"Yes, we’re done for today. More importantly, I have a present for you."
"A present?"
"Hehe... I think you’ll quite like this one, Ryoma-kun," Elize said with a smile.
Reinhardt stepped forward carrying a stone box.
"There is a monster inside. It’s a weak one, but be careful when you open the lid," Reinbach warned.
Intrigued, I carefully pried open the lid. The moment I saw what was inside, I was mesmerized.
"A slime?"
Inside the box was a dull, metallic-colored slime, unlike any I had ever seen, wriggling around in search of an exit.
"It’s a Metal Slime, a rare evolved species. We happened to find it and caught it for you."
"I can really have this? Thank you so much! I'm thrilled! Another new species..."
"It’s still a monster, so you should establish a contract first," Reinbach reminded me.
Right, of course.
I snapped out of my trance and performed the taming contract. The Metal Slime calmed down immediately. When I picked it up, it felt cold and metallic to the touch. It was also significantly heavier than any other slime I owned. Since it was a Metal Slime, its diet probably consisted of metal.
"That reminds me, Reinhardt-san. May I take some of the iron-rich soil to use as food for this slime?"
"You're going to feed it dirt?"
"Either the dirt itself, or I'll extract the iron for it. I’d also like to try giving it to my other slimes to see what happens."
"If that’s the case, take as much as you want. It’s just waste from the mining process anyway. We wouldn't even have given it a second look if you hadn't brought it up."
"Thank you!"
I could pile it up in a corner of my Dimension Home and have enough to last a long time. It eats iron, huh? I wonder if a normal slime will turn into a Metal Slime if I feed it enough iron? Or maybe something else entirely... I couldn't wait to find out.
"By the way, Ryoma-san, what were you doing just now?" Elia asked.
"Oh, I was increasing my slime count and doing some combat training..."
"Training... slimes?"
Elia looked skeptical. I could understand why. Even if she acknowledged how useful slimes were for utility, their combat potential was a different story. In the eyes of the world, they were Rank G monsters that even a child could kill. And frankly, that assessment was usually correct.
However, slimes possessed two incredible traits: a semi-liquid, flexible body, and the fact that they wouldn't die as long as their internal nucleus remained intact.
Furthermore, a slime can move its nucleus anywhere within its body. For example, if it's about to be kicked, it can shift its nucleus to the side furthest from the impact and use its semi-liquid body to absorb the shock. Even if it's sent flying, it can do the same upon landing to negate the damage. I believed I could weaponize those traits.
I used to think wild slimes were too slow for this, but after spending so much time with mine, I realized they had become significantly more agile. I’d been training them in the forest ever since.
I’d taught them grappling techniques to dive under an opponent's weapon and entangle their limbs. I’d taught them defensive maneuvers to parry strikes by shifting their mass. By now, some of them had even learned how to extend parts of their bodies to wield spears and poles.
"Mind you, in a one-on-one fight, they still can't beat a goblin. They’re still overall lacking in power."
"No, no... the fact that a slime is using a weapon at all is plenty amazing," Reinhardt muttered.
"Ryoma-kun," Reinbach said, "perhaps you should take a beginner's course at the Tamer Guild? It might help you understand what 'common sense' looks like."
"Shouldn't we be asking Ryoma-kun to give the course instead...?" Elize whispered.
I’d had a feeling my slimes were a bit unusual, but they were being quite blunt about it.
I offered a quick word of thanks to the three adults, who all looked suddenly exhausted for some reason, and then went to collect the red iron-soil from the slag heap. Elia kindly offered to help me.
By the time we were ready to head back to town, blocks of red soil were piled like a mountain in a corner of my Dimension Home.