“Well, this is it,” I said to myself, examining the barren room as I placed the satchel of belongings that had been gifted unto me on the floor. “My new laboratory and home.”

It had taken some time to press the point, but I had managed to convince Tycelius to provide me with a home on the outskirts of some village close to the castle town, alongside with a few books of my choice and a decent sum of gold. Now, one week after my initial introduction to this world, everything was about to begin.

If anything, I had to argue for them to reduce the compensation they were offering – their initial stance was to have me live as a member of the royal guard in service to the king, saying some bizarre notion that ‘anyone who comes from the world of a Hero has to be formidable indeed’, but I (hopefully kindly) declined that offer. I had no wish to tie myself down to royalty.

Besides, I wanted to prove myself. There was an entire world of science just practically waiting to be explored. I didn’t need to fight the Demon Lord. If I remembered the rumours correctly, Shinya and his party were currently out travelling the lands, putting down threats such as bandits and goblin encampments to raise his Level. All I needed to do now was sit back, relax, and thoroughly immerse myself in magical biological science, as otherworldly as it sounded.

The books I chose weren’t anything special. Heck, they’d bought it from one of the bookstores in the capital city of Everach. Their contents, though, were priceless to me. A few volumes detailed a bestiary of common beasts native to the lands of Everach, and just looking at them, I was beyond fascinated.

There were things like thunder lizards, Stegosaurus-like creatures with a singular horn on its head, that could flash a vibrant yellow and release a jolt of lightning. In the Windspear hills on the farthest corners of the kingdoms, Wind Wyverns that resembled pterodactyls with a draconic-looking head could release massive gusts of wind with each beat of their massive wings. Then there were the Elemental Drakes, that formed herds, each of which consisted of a single element scattered in hills, plains, mountains, and caves across the land. Drakes were the land-based variant of dragons, looking like someone crossed a Tyrannosaurus Rex with an actual dragon, and they could unleash potent elemental blasts with their breaths.

Among them, there were many oddities that struck me as being extremely strange. For example, there existed something they called Fire Eels, a fairly common type of aquatic animal that was valued for harvesting of its flesh. Apparently, it could be used by [Alchemists] to create Fire Oil, which when placed over a weapon, gave it a mild fire element property. Low-level adventurers frequently made use of it to boost their capabilities.

It made absolutely zero sense to me. Why would a fish, living underwater as it was, develop the ability that resulted in a fire-based phenomenon? How exactly would they have been selected for over long eons with the invisible hand of evolution acting on them? There had to be something missing there.

Even what I thought were mundane creatures turned out to have some magical properties. The common boar’s tusks could be ground and powdered with pestle and mortar, mixed with herbs, and with the right alchemical processing, made into a tincture that enhanced one’s strength. Alchemy in itself wasn’t of the sort I was used to in my readings of the history of chemistry: here, rather than the proto-chemistry that was alchemy, magic was directly used in the process of brewing potions, oils, and tinctures, infusing a mixture with what another book had referred to as ‘pure mana’.

Alas, only [Alchemists] could create potions in this way with their [Class] skills, and so I was flat out of luck. Ah, well, Biology was always my main interest, anyway.

I moved the furniture in the room slightly, designating one corner as my space for benchwork, another that would serve as an incubation chamber, and yet another to store all my precious books and future research notes. I had managed to wrangle some equipment from Tycelius, although he was bewildered by why a non-[Alchemist] would desire a set of basic alchemy reagents and equipment, ranging from flasks and dishes, to a distillation set-up and more than a few tubes.

Reverently, I placed an object that sparked a sense of wonder within me on the bench – it was almost like a Bunsen burner, except there was no gas inlet or outlet line. Instead, it was driven by the energy of a mana-stone, a form of crystallised ‘mana’ that suffused all life in this world, and could be retrieved from powerful beasts. An [Artificer] designed the exact magical formula that would convert the mana of the stone into a jet of flame, although I had no idea how that was even done. Was it a science, based around set rules and systems, or was it more whimsical, with the formula taking shape based on the [Artificer]’s desire?

I didn’t know. For now, I had to leave that particular curiosity aside.

I knew I had to start small in this world. I couldn’t go from regular old molecular biologist to Dragon physiology expert in one day. There was so much I needed to understand – just what was mana? How did it relate to life, and why was it unique to this world? How much of what I knew back on Earth was still relevant here?

The simpler the model, the greater the ease of understanding, although translation to other models may be less clear-cut. From there, knowledge had to be increased step by step, transferring inferences and refining theories along the way. The ideal experimental model had several characteristics: easy to maintain, possibility of breeding, a variety of reagents made available, and a decent representation of whatever it is the scientist wanted to study. It was why C. elegans and zebrafish so pervaded the biological sciences, especially in the field of developmental biology.

I wanted to start small, and so Drakes, Wyverns, and Thunder Lizards were out of the question. Even mice that I was used to back on Earth were not worth the trouble, since the breeding cycle took approximately a month anyway, and yet another two before they were fit to be used for experiments. I was raring to go; I couldn’t wait that long!

Therefore: I chose the simplest model of all. I turned my gaze on the poor creature that would now serve as my experimental model, a practical gold mine to any budding scientist.

Slurrrp!

…a Slime.

Yes, that was right – this world had Slimes. They looked uncannily similar to those of the Dragon Quest series or Maplestory, which was to say that they were just simple blobs. They were treated as harmless pests here, and people more often than not simply left them be. They weren’t intelligent, and didn’t cause any trouble. In fact, they helped clear up things like fallen leaves, absorbing them into their bodies.

They multiplied every few days, splitting into a second fresh slime. Occasionally, when their numbers got too high, people would take them, puncture their gelatinous membranes, and use the resultant liquid that spewed forth as a soup broth or to make a jelly.

I loomed over the Slime, cackling to myself, unheeding of what other people may think since there was no one around anyway. The Slime continued bouncing on the spot, not at all reacting to my presence. It was almost cute.

Alas, the pursuit of science demanded sacrifices. This Slime would be the start of my career as a [Biologist].

“Sorry, buddy,” I said, trying to steel my heart, as its head moved from side to side, wide little eye-like blobs looking at me with incomprehension. “Well… here goes.”

There was something I wanted to test. In my reading, they had said that Slimes could exist without having a food source, and indeed was the only reason why people tolerated their presence, since it wasn’t even a crop pest. As far as people knew, they simply swelled in size, split, and repeated the process over and over.

I, however, didn’t believe it was that simple. Careful not to pierce its membrane, I placed my finger against the Slime’s body.

[Bio-analysis].

I wasn’t performing something like attempting to discern how magic and biology interacted. That was out of the scope of my comprehension, and therefore my class skills. What I wanted to do was to examine the Slime as I would any other form of life back on Earth.

Information flooded my mind. As though peering down a microscope, I could see the cellular structure of the Slime’s surface. A continuous layer of cells encircled its form, with something reminiscent of tight junctions and gap junctions connecting them together. Within that layer, was a nutrient-rich broth that formed the majority of a Slime’s body.

In other words… it was almost similar to an open circulatory system, not unlike an insect’s. The liquid core provided what was needed to sustain cellular life on the exterior surface. Their equivalents of tight junctions held the cells together, preventing the pressure from within from simply rupturing the body, but a sufficient external force could still do that all the same.

My first hypothesis was proven correct, then. Time to test the second.

I gingerly took hold of it, placing it in a tank of salt-water. While waiting, I jotted down notes in my lab book.

“Slime’s body is fully contiguous, with networks reminiscent of zonulae occludentes and maculae communicantes joining them,” I muttered, penning my thoughts. “Can strength of junctions be modified? How would it affect ease of membrane rupture? Do all Slimes have the same properties, or are they on a continuous scale? Is breeding Slimes possible? How are they related to other forms of life? Do they fit at all into the phylogenetic tree?”

My thoughts flowed out freely, experiments already budding and taking hold in my mind. More samples required, I concluded. Viability of breeding dependent on possibility of Slime-fusion.

After several minutes, I glanced at the tank that the Slime had been placed in. Carefully, I placed my hand in it, scooping out the poor Slime.

Unbidden, I smiled.

The Slime had shrunk. The observation supported my second hypothesis.

Water moved from a hypotonic solution to a hypertonic solution, if separated by a partially permeable membrane capable of solute retention. In this case, just like how the intracellular, extracellular, and intravascular fluid spaces were separated by cell membranes in every other animal, giving rise to drastically different fluids in each of those spaces, so too did the Slime’s body separate its internal ‘broth’ from everything else in the outside world.

The reason why it increased in size was probably due to water entering its body. To do so, it would need to generate an internal environment of high solute concentration, which meant that it had to be capable of absorbing things inside as well. Was that driven mechanically, in the same way humans ingested food, or chemically, such as by active transport of salts across the cell membrane by specialised proteins?

Or, I thought with growing excitement, by magic? What made the Slimes eat fallen leaves, or other stray bits and bobs, as I had heard both in that book and from the bizarre look Tycelius gave me when I questioned him on the subject of mundane Slimes?

Unfortunately, this wasn’t yet the time to test that. One more test awaited this Slime.

I dunked the Slime into a tank of the purest water I could procure. Again, I waited.

Within a few moments, I heard a soft ‘pop’ emanate from the tank. Slime, you will be missed.

Carefully, I reached into the tank, retrieving what was left of its body – a soft, almost silken membrane, that had once been the exterior of its body.

There were two things I wanted to do with it. The first – as a partially-permeable mesh for my experiments. Already, I knew that the network was fine enough to selectively let only water through, allowing it to act as a cell strainer. I needed to collect more samples from other Slimes, or find alternatives that would let me selectively separate out different components of interest. Back in the lab, I was used to working with 100 micron, 70 micron, and 40 micron cell strainers, each of which had different properties. The Slime’s membrane was many times finer than that, and so I needed something coarser.

As for the second: I scooped a small ladle of water from the tank, placing it into several empty petri dishes. Then, I cut a small section of the fine membrane into each, adding additional supplements into each dish, documenting in my lab book just exactly what was added. Sugar, yeast extract, ammonia…

My thought process was simple. The Slime’s interior had to be a nutrient-rich environment to support it. It was why it could be used to make soup broths and jelly.

In other words… ready-made culture media and culture agar.

At the same time, the exterior membrane of the Slime was a continuous cellular layer. Would they continue growing and spreading if left in culture media? How would they grow – as a 2D monolayer, or would they somehow fold (as if by magic!) to grow a new Slime from within the two-dimensional base of the petri dish? And what if I provided a supportive matrix, not unlike the Matrigel or other collagenous supports I had frequently used back in the lab?

Yes… I would need to collect a lot more Slimes. With what I had in mind, I might even need to start a Slime farm. Given what I already knew about the Slime’s biology, it shouldn’t be too hard – find a solution isotonic with the Slime’s body, dunk it inside, and a fresh Slime should pop out soon enough. So long as the osmotic potential was balanced, the Slime wouldn’t burst.

My first project: Slime Tissue Culture was a go.

“What in the –“

At that precise moment, I felt a rush of something course through me, and I knew without a doubt that I had achieved Level 2. A smile slowly spread across my face.

This world – and its magic – was bizarre indeed.

More importantly, though…

I had a new skill. [Bio-Acceleration: Tissue Culture], it called itself. It didn’t do much beyond hastening samples currently being used in tissue culture. It saved a decent chunk of time, but was not of practical benefit outside of tissue culture. Most people would have scoffed at it, since it was useless in combat.

For me, though, who had slaved my life away in front of the tissue culture hood for far longer than I would care to admit, it was a godsend. From what I understood my intuition was telling me, expending mana on this skill would allow for samples in tissue culture to be accelerated, condensing two hours’ worth of growth or experimentation into one. With more use, and greater mana expenditure, that factor could be increased even further.

Looking at what I had on hand, that smile turned into a wide grin of almost maniacal quality.

This… this would do nicely.

-o-o-o-

Before I knew it, two weeks had passed, and I was already Level 4. Still no new skills, however.

Now, I stood in front of my tissue culture incubation zone, eyeing the wide selection of petri dishes I had on display. After a long period of experimentation, I had chanced upon something mildly interesting. Depending on the exact constitution of the culture media used, the sheet-like translucent membrane in contact with the layer of Slime agar coating the dish adopted slightly different physical qualities.

Absolute osmotic potential altered the pore size of the sheet. Normally, this wouldn’t have been known, even by the Slimes themselves had they any notion of intelligent thought in them, since having pores large enough to allow solutes through without keeping them retained would inevitably mean that water would escape from their bodies. That, in turn, would result in them dying.

Grown as a two-dimensional layer, though, that was no longer true. And therefore, I now had access to sheets of Slime-membrane, with pore sizes strict enough to filter out exactly what constituents I desired. I had large ones, that strained out cells from everything else, smaller ones that kept both intact cells and cellular debris, and even smaller ones that allowed for selective passage of things as small as bacteria and virions, close to what the original Slime’s membrane had been like.

Then there were other factors yet. I could alter the absolute thickness of the sheet through introducing increased glucose and nitrogenous metabolite contents. If that wasn’t enough, it turned out that when sheets were grown separately as thin layers, placing them on top of each other somehow fused them together, complete with the associated tight-junction-like connective proteins that might be expected.

Oddly enough, this only worked when I layered membranes obtained from the same initial Slime. If I attempted to place the membrane cultured from another Slime onto it, the two would stubbornly remain separate.

I had no idea how that could happen. The speed at which the binding took place was blindingly-fast, unable to be explained by transcription, translation, and transport of new proteins to the cell surface for formation of these cellular junctions. In the end, it all boiled down to magic.

And magic was precisely what I wanted to research. More specifically, how magic altered and interacted with biological life here on this world.

Slime farm was going strong. To keep experiments consistent, I kept them ‘breeding true’, taking care to note the Slime of origin because it seemed that different individual Slimes had subtly different physical properties, most notably in their pore size, thickness, tensile strength… and cuteness.

That was precisely what I was struggling with now, as a newly captured Slime that wandered its way into my home stared at me with wide eyes.

“Sorry little buddy,” I said. Its eyes shook, his entire tiny gelatinous body quivering, and I swore it made a low whine despite lacking a larynx in its body. “Come on now… don’t make this harder than it has to be…”

Little teardrops emerged from its eyes. I didn’t even know how the eyes worked – as far as I could tell, they were simply there, not at all connected to nerves or a brain like those of a human. Hell, from my [Bio-Analysis] of its structure, it didn’t even look at all like a photoreceptor.

How could it see? Why even have something that looked like eyes?!

I had asked myself that over and over again, for close to two weeks now. And at last, I found the answer.

To make me feel like a piece of shit for wanting to end this poor Slime’s life.

As if sensing my thoughts, it bounced a little closer from where it was on the table, eyes shining with hope.

Gah… how was it that I could handle hundreds, possibly thousands of mice over the course of my experiments, and this cute little Slime was making me second guess myself?

“It’s for the sake of science…” I told myself, steeling my heart. “Please understand…”

Then, it wailed. This time, I definitely wasn’t imagining that soft whine, alongside the practical deluge of tears that was slowly but surely causing the Slime’s body to shrink in size.

This had never happened to the previous thousands of other Slimes I had already harvested.

A thought occurred to me.

“You can’t like… understand me, can you?”

It tilted its head – well, his ‘head’ was his entire body – to the side, before bouncing on the spot once.

“What does that even mean?!”

Again, it bounced.

I sighed. “You’re not like… that guy from Tensei Shitara Suraimu Datta Ken, are you? Satoru Mikami? Rimiru, or whatever?”

Yes, I was isekai trash. Still, the Slime looked almost confused at that question, flipping its body a full 360 degrees, and my traitorous heart wavered.

So cute…

“Let’s try this,” I said. “Jump once for yes. Twice for no. Can you understand me?”

It jumped…

My mouth fell wide open with shock.

…and then it did so again. It stared at me cheekily, as though sending me a challenging look.

“I’m warning you,” I said in a low voice, grabbing it as it squealed. Its entire body wiggled in my hand, something no other Slime had done before. Shocked, I dropped it once more.

There was something different about this Slime. It wasn’t unintelligent and unresponsive to threats like other Slimes were.

This Slime, for better or worse… was intelligent. Excitement swelled within me. There was so much there I wanted to understand. How was it intelligent? Slimes had no nervous systems, no brain or other organ capable of processing complex thought. They were a simple layer of cells surrounding an inner reservoir of fluid capable of sustaining physiological life.

Was magic responsible?

If so, I needed to understand it. At present, though, I didn’t have the tools, theories, or skills required to even begin an investigation into this unique Slime. All I could tell was –

“[Bio-Analysis],” I said aloud, even though I didn’t actually need to in order to utilise the skill.

– yup. As far as I could tell, on the cellular level, this Slime was no different from any other.

“Damn my bleeding heart,” I said, sighing, reaching out to touch the Slime. “Fine then, buddy. You get to live.”

It squealed in delight, hopping off the table, rubbing its body against my leg, with an adorable squish sound one might expect from these gelatinous creatures.

“You need a name,” I declared after a few moments, once it was done with its little display of affection to its would-be abductor and killer. Was this some bizarre form of Stockholm Syndrome? Well, whatever. I racked my brains for several seconds, before finally speaking. “Hmm… how does Slime-bro sound for you?”

Yeah, I had no originality or creativity. Sue me.

It squealed, bouncing once on the spot, before its body lengthened vertically, almost like it was giving a Slime-salute. This really wasn’t a line of thought that was helpful for my long-term mental stability, and therefore I decided it was best to continue on with my actual job.

“Stay here,” I warned sternly, after I knelt down and scooped it up, placing it back on the table. “Unless you want to watch me vivisect and grow out the skin of your distant, distant cousins, I’ve got more experiments to tend to.”

It, however, leapt off the table once more, landing on my shoulder. I stiffened momentarily as its cool touch, but it nestled itself against my ear, its body jiggling lightly.

“You want to watch?” I asked incredulously.

Don’t get me wrong, I was flattered and amazed that someone took interest in my experiments, but… well, it’d be the equivalent of me watching a scientist blow up a human by immersing them in a tank of water, then collecting his skin, before placing it in petri dishes and attempting to grow and harvest them.

Not a very pleasant thought, eh?

Slime-bro bounced once, and gave a quiet trill that I interpreted as affirmation.

“Well, then…” I said, honestly unsure of what to make of him. Still, science was waiting to be done. “I guess I’ll explain my experiments, then. See, right now, I know that Slimes don’t fuse when in contact with each other, but somehow their skin does when separately grown in culture conditions.

“Simply placing a membrane against a living Slime doesn’t change its membrane either. Therefore, I’m attempting to see if the resultant fused membranes continue to propagate in tissue culture, and if so, whether or not there is a limit. Eventually, I’m hoping to see just what it is in living Slimes that rejects this phenomenon.”

I didn’t know whether or not to be worried, but Slime-bro made a sound that seemed almost like he was cackling in delight. Hopefully it was just my imagination.

Still… it was fun having company around. Perhaps Slime-bro would somehow be intelligent enough to become an assistant of sorts?

I chuckled. Yeah… like that would ever happen.

Wait… what did I just say? I stood there, completely still.

“Rejects this phenomenon,” I repeated to myself.

A dozen thoughts raced in my mind, slowly at first, before increasing in rapidity and lucidity.

Rejects.

I was an immunologist. Tissue rejection, while well-documented early on in the transplant field, had later been discovered to be due to incompatibility of major and minor histocompatibility antigens at various genetic loci between donor and host. There were a whole host of other factors, but in general terms, an autograft involving transfer of a graft onto the same individual wouldn’t be rejected by the immune system.

In that same vein, different Slimes rejected each other’s membranes.

Membranes grown from the same parent Slime did not reject one another. Those grown from different Slimes, however, did.

“Ah, hell,” I swore softly, as I realised something I should have about a week ago, when I first discovered that phenomenon. “How the hell hadn’t I seen that before?”

What do I do with this information? My mind was awhirl with ideas. Still… how? I could only grow membranes from a dead Slime. For whatever reason, once a Slime split into two, the two resultant progeny were seen as separate, and rejected each other. I needed to somehow culture membranes from a Slime without causing its death, if I wanted to modify a Slime’s membrane thickness.

Why, you may ask? An excellent question.

The answer: simply because I could.

Still… how? I couldn’t cut a piece of membrane away without killing the Slime, since its fluid would just leak out.

In the end, despite my deliberations, the only way to achieve that would be for the Slime to shed a piece of its membrane on its own. In other words… membrane invagination or blebbing, like what I knew regular, mundane, boring, non-magical cells did.

How would a Slime achieve that? It would need to be intelligent enough to –

Abruptly, I turned my head toward Slime-bro, who had been watching on with extreme curiosity all this while. He wasn’t smart enough to obey complex commands like that, but much like a pet, perhaps, just perhaps…

“Hey there, Slime-bro,” I said with a grin on my face. “How would you like to become a thick-Slimeboi?”

I saw that I had its complete attention, and I began cackling in delight.