Afternoon.
"—And that was the gist of it."
After weighing my options, I had decided to give Niki a crash course on every species of slime I owned. I covered their various uses and gave him a brief rundown of how some of them had evolved.
Niki stared at the rows of slimes lined up across the table in the now-empty dining hall, his eyes wide with curiosity. He seemed receptive enough, but I wondered how much had actually sunk in.
"Is there anything else you want to ask about? Or any slimes you’re particularly interested in?"
"Hmm... in that case, the Medicine Slime! If someone gets seriously ill or injured, we have to travel all the way to the next village. Having one of those around would be huge."
That was a far more practical reason than I had expected.
"It’s true that they produce fluids that work as disinfectants and wound medicine," I said. "They’re quite useful for treating minor injuries. However, they can also produce deadly poisons. Since their diet consists of toxins and drugs, Medicine Slimes are actually quite difficult to manage. For a beginner, I’d personally recommend the Heal Slime. They can use Healing Magic, and you can keep them healthy with nothing but water and plenty of sunlight."
"I see... but slimes that can use magic are rare, right? They must be worth a fortune. You’ve got five different types, counting the Heal Slime, Big Brother."
"Yeah. In my case, it’s because the slimes I was already raising happened to evolve, but apparently finding them in the wild can take years. An acquaintance of mine who knows a lot about monsters mentioned that almost no one has a collection of five different magic-using species. As for the price, I’m not entirely sure... but it seems there are plenty of nobles who want things just because no one else has them, which drives the prices up. They’re probably popular as 'rare pets' for people who like to show off."
"I get why they’d do it, but I don't really get the feeling," Niki admitted.
"Don’t worry about it. You’ll probably understand eventually, and even if you never do, it won’t exactly make your life harder."
It was only human nature to compare oneself to others. He would likely realize that and struggle with it as he grew into an adult. But if he could avoid that trap entirely, he’d be spared a lot of misery. I figured that wouldn't be a bad way to live, either.
"Huh... oh, I know! You said before that their evolution changes based on what they eat. If they keep eating fish, would they become Fish Slimes or something? Do those even exist?"
"The number of slime evolutions is so vast that even professional researchers can’t keep track of them all. I don’t know if Fish Slimes exist, but I think it’s certainly possible. For example, my Metal Slimes and Iron Slimes branched off based on whether they ate a variety of metals found in the local soil or if they ate only iron. Given that, if there were slimes that ate only copper, tin, or lead... I think there’s a high probability that entirely different species would be born."
To take it a step further, the idea that evolution was determined solely by diet was merely my current working theory. In fact, lately I had begun to suspect that even that wasn't the whole story.
"Is the theory wrong?" Niki asked.
"Well, saying it’s 'wrong' might be an overstatement."
As far as my observations went—especially with the Sticky, Poison, Acid, and Cleaner Slimes I had been researching since the beginning—I had been able to control and reproduce their evolutions based on what I fed them. Therefore, the fact that diet influenced evolution seemed indisputable.
"But it feels like something is missing. Diet is definitely one of the conditions that determines the path of evolution, but I suspect there might be other hidden factors that separate one species from another. For instance, take these Weed Slimes. They’re a species that evolved from eating common weeds, but recently, a few of them started eating poisonous and medicinal herbs. Normally, you’d expect them to evolve into Poisonous Herb Slimes or Medicinal Herb Slimes, but..."
"Wait, wasn't poisonous grass the food you used to make Poison Slimes?"
"Exactly! That’s exactly the point. Up until now, slimes that ate poisonous herbs became Poison Slimes—essentially 'toxic slimes.' Right now, I’m waiting for these Weed Slimes to finish their evolution process. If they don’t turn into Poison Slimes after eating those herbs, then I’ll know for sure that there’s 'something' else that differentiates a slime that eats poison from one that eats poisonous plants. If there are truly so many types that researchers can’t keep track, then it wouldn't be strange if they were further subdivided. Strictly speaking, Acid Slimes eat bones as their primary food, yet they haven't become 'Bone Slimes.' I believe they evolved specifically to enhance their digestive capabilities so they could consume bones."
"...You look like you’re having the time of your life, Big Brother. Even though you’re talking about being wrong or not knowing things."
"Haha, well, searching for the answer precisely because I don't know it is what makes it fun. You observe, you form a hypothesis, and you experiment. If you find out you were wrong, you acknowledge it, rethink your strategy, and try again. The moment you finally find the answer makes all that effort worth it."
"Huh. If you say so."
Oops... was that a bit too much? I had intended to keep things simple, but once I got passionate about my research, I tended to get carried away.
"Hmm... look at it this way. It doesn't have to be about slimes. Don't you feel happy or excited when you finally become able to do something you couldn't do before, or when you learn something brand new?"
"Oh, I guess I get that. Like when I finally learned to climb trees, or when we finished the secret base... or even right now, I guess!"
So he was having fun right now? As I thought, Niki had a real knack for this.
"In that case, do you want to try helping me take care of the slimes for a bit?"
"Is that okay?"
"Of course. It’s mostly just giving them food and water, but when you have this many different types, even the preparation becomes a major chore. I have to prepare specific meals for the slimes waiting to evolve, so you’d actually be doing me a huge favor. I have supplies on hand, but if possible, I’d like to get some local materials to use for the experiments as well..."
"Then let's go ask Mom and the others! At the very least, I know where all the trash is!"
And so, after making the rounds through the village with Niki...
"We really gathered quite a mountain..."
A corner of the square that had been lent to us for temporary storage was now piled high with massive heaps of junk and refuse.
Niki was a bold kid with a naturally friendly personality. He charged into various houses and shops, successfully securing all sorts of discarded items from the adults. It probably helped that Niki was the one asking; the villagers seemed more comfortable dealing with him than with a stranger like me. He was a massive help.
Better yet, when I summoned my slimes and showed them the haul, several of them reacted immediately. It seemed the pile contained several new types of food they were interested in!
"Whoa... that's a crazy amount. Big Brother, have you really been keeping this many? Space Magic is awesome."
"No time to stand around being impressed. First, we need to check which slimes want which items and sort everything out. If we don't hurry, the sun will be down before we're finished."
"Got it!"
We worked together to sort through the "gifts."
The children playing in the square and the local adults watched us from a distance, but I ignored them. The news of what we were doing had already spread through the village, so I didn't feel the need to offer any further explanation.
I focused entirely on the task at hand.
"First... let's look at this."
It was waste from the processing plant. It was a mixture of inedible fish parts—guts, bones, and various offal.
The ones reacting to this were the Scavenger Slimes, the Acid Slimes, and a single Bloody Slime.
The Scavengers were interested in the organs that had begun to spoil and the waste inside the digestive tracts. The Acids seemed to want the bones, which was their usual diet, so nothing unusual there.
However, the Bloody Slime was another story. It wanted the internal organs. At first, I thought it was after the blood remaining inside, but the other two Bloody Slimes I had on hand showed zero interest. This suggested a high possibility of a new evolution.
The question was what, specifically, it was reacting to. When I gathered the specific parts that triggered a response, it only amounted to a tiny fraction of the total pile. Furthermore, the slime didn't seem to care about the species of fish or the type of organ. I could pull out the exact same organ from the exact same type of fish, and more often than not, the slime wouldn't react at all.
Just then, Niki spoke up.
"Big Brother, I think I figured it out."
"Oh? What is it?"
"It’s probably parasites. My dad and mom always say there are certain fish you have to be really careful with this time of year. Almost everything you’ve sorted into that pile is one of those types."
"I see. Parasites, huh... Appraisal."
Heap of Fish Offal: A pile of internal organs collected from multiple species of fish. Various organs contain the eggs of parasites native to Lake Latoin, or early-stage hatched larvae.
"Bingo! Niki, you’re exactly right! When I used Appraisal Magic, it confirmed that every single piece in this pile has parasites in it!"
"Seriously? Heheh. But parasites, though... that's kind of gross."
"Is something wrong?"
"I mean, parasites are just a pain in the neck. No one wants them around."
That was true. They were pests, especially in a village that relied on fishing for its survival.
"But look at it this way," I said. "I gathered this specific pile of organs because I saw how this Bloody Slime reacted. I didn't even know there were parasites in there until I used Appraisal. To put it another way... if we use a slime that eats parasites, we can instantly tell if a fish is infested. Don't you think that’s a pretty incredible possibility?"
Niki’s eyes went wide. I could hear gasps from the adults who were eavesdropping nearby.
"Oh, I get it! If we can tell which fish don't have worms, it'll be way safer to eat!"
"Fish without worms... if we knew that for sure, we could even eat them raw..."
"Don't you even think about it! I’m the one who has to look after you when you ruin your stomach!"
"I’m not a moron; I wouldn't eat it raw this time of year. But in the summer..."
The buzzing among the adults grew louder as they listened to Niki's excitement.
"Niki, do people around here actually eat raw fish?" I asked.
"There’s a season when the worms aren't as common. It’s a way of eating that only fishermen can really get away with. My dad loves it, but he ends up sick every year anyway. Even when there are fewer worms, it's never a guarantee."
"I see."
It reminded me of the people who insisted on eating blowfish back when it was banned by law during the Edo period. Since these parasites weren't usually fatal, perhaps they were just more casual about the risk.
Setting that aside, the real prize was the Bloody Slime’s evolution. What would happen if it evolved by eating parasites? A Parasite Slime? Would it live inside a host? Wait... a Bloody Slime’s body is made of blood. If that blood enters a human body, would it act like a blood transfusion?
Now that I thought about it, when a Bloody Slime sucked blood, it entered the victim's body through the wound. But it didn't cause the prey’s blood to clot, did it? It seemed to flow in and out smoothly. I had heard that mixing incompatible blood types caused solidification... for that matter, what was a Bloody Slime’s blood type anyway—
"—Brother! Big Brother!"
"Whoops, sorry Niki. I was lost in thought."
"It was written all over your face. Anyway, we figured out the parasite slime, so let's keep going!"
"You're right. Let's do it!"
We still had a massive amount of trash to go through. To me, however, it looked like nothing less than a mountain of treasure.
And it didn't take long for me to realize that I was absolutely right.