Returnee from Another World - Chapter 4: Body Modification through Alchemy

Chapter 4: Body Modification through Alchemy

For the roughly three years it took to find the petals of the thousand-year grass, I wasn’t solely focused on that search.

The contents of the book Arugabana contained so much astonishing knowledge about alchemy—even for someone like me, who’d become quite versed in it—that it was brimming with new discoveries.

Among them was bio-alchemy involving living organisms, and the slime I used this time was one such creation.

*

A secret art to captivate the opposite sex.

This technique makes a target mentally and physically dependent on another, unable to break free.

It uses pleasure to create that dependency.

In that world, there existed slimes—a staple monster of fantasy settings.

They weren’t particularly dangerous. Omnivorous and capable of eating anything, most lacked strong digestive enzymes, except for a few highly acidic types. For humans, they weren’t much of a threat.

But slimes had an interesting trait.

Their attributes and behaviors were determined by the food they consumed. Once set, they’d prefer that food exclusively, barely touching anything else.

Of course, in the wild, their preferred food could run out entirely.

Slimes could move, albeit slowly, so they’d wander in search of their food.

But if they still couldn’t find it, as a last resort, they’d attempt to parasitize another creature.

In an environment where they couldn’t survive without food, they’d try to merge with another organism to persist. Naturally, the host wouldn’t easily allow such an intrusion, so it rarely succeeded.

If assimilation did occur, the slime could sense the location of its preferred food and secrete a special mucus to communicate this to the host.

That’s the extent of what I learned about slimes’ ecology—their secondary symbiosis.

And this is where alchemy comes in.

During the process of a slime’s nucleus splitting and multiplying, the offspring nucleus strongly inherits the parent’s attributes.

That said, the attributes aren’t fully fixed, as the offspring’s diet immediately after splitting can alter them slightly.

However, a completely attributeless slime doesn’t exist. Even right after splitting, they inherit some of the parent’s attributes.

But for bio-alchemy, I needed a near-attributeless slime—or as close to it as possible.

To achieve this, I placed a freshly split offspring nucleus into a culture medium filled with mana potion.

Mana potion is derived from mana, which is inherently attributeless.

Strictly speaking, it’s not completely attributeless due to water and other impurities, but it’s close enough.

Then, while raising the slime in this medium, I fed it the parent nucleus’s preferred food. This diluted the attributes.

The offspring’s attributes became weaker than the parent’s. This process was repeated over multiple generations.

Each splitting cycle took three to six months. It took over two years to create a near-attributeless slime.

Once the first stage was complete, I moved to the next step.

Now, I had to imbue the attributeless slime with a new attribute.

I removed the slime from the mana potion culture and placed it in a breeding tank, feeding it my semen, occasionally mixed with saliva, sweat, or urine. After about two months, the attribute stabilized, and the slime’s attribute—or rather, its primary food—became my semen.

The third stage involved altering the slime’s behavior.

The material used was incubus bodily fluid.

The fluid secreted by an incubus is far more potent than any drug in this world.

Since my sexual target was female, I used incubus fluid. If the target were male, I’d have used succubus fluid.

Of course, neither incubus nor succubus fluids affected me, so I couldn’t verify their effects.

According to Arugabana, the euphoria, bliss, and sexual pleasure from these fluids could transform even the most virtuous maiden into a depraved creature instantly. Such substances were rare, even in that world, and finding them was no easy task.

In the end, I tracked down a noble in a far northern country who had summoned and enslaved a single incubus. The noble himself was a demon, naturally.

I infiltrated his mansion, swiftly beheaded the enslaved incubus, and dismembered its body. My dimensional storage can hold almost anything, even living creatures, but for some reason, it won’t accept anything I can’t lift with one hand.

After tossing the dismembered incubus into the dimensional storage, I interrogated the noble, offering his life in exchange for the method to summon demons.

The amount I obtained was enough for one batch of material, but if I could summon them myself, I wouldn’t have to go through such trouble again. I wanted to secure a reliable source for the future.

However, I gave up quickly when I learned the summoning required a thousand human sacrifices.

To get back on track, I fed the incubus bodily fluid to the slime alongside its regular food.

The slime’s attribute didn’t change, as it was already fixed. But, fascinatingly, after a while, the slime began secreting mucus with the same effects as the incubus fluid whenever it ate. This was the behavioral change.

As mentioned earlier, even after assimilation, the slime secretes this mucus in small amounts when it senses its preferred food nearby—probably like drooling in excitement.

This was the true nature of the slime I used on Ayano.

It would take two or three days for it to fully assimilate and take hold. Once that happened, Ayano would be unable to leave me.

Imagining that moment, I couldn’t help but feel a stirring in my groin.

Come to think of it, I’d been so engrossed in my research that I hadn’t been with a woman in a long time.

But I had no intention of touching her now.

I wanted to savor the process of Ayano becoming dependent on me, falling completely. That’s what I desired—it was also my way of getting back at her for drifting away from me.

*

“My body feels heavy.”

The next morning, when I went to the living room, Ayano was still there.

Even in a coma, the pollen’s effects should wear off naturally, and she should recover.

It probably takes about five or six hours to wake up. I’m not sure exactly when she woke, but it seems Ayano didn’t return home.

Still in the sweats, she was half-reclining on the sofa, fiddling with her phone.

“You probably caught a cold.”

“Hm… Maybe. I feel kinda feverish. Got any cold medicine?”

“There should be some in the cabinet by the kitchen. Help yourself. More importantly, go home and rest. I’m heading to school.”

It’s probably the assimilation. There shouldn’t be any pain, but some discomfort is unavoidable.

She’ll likely feel something off in her body for two or three days.

“No way, I’m staying here.”

“Huh? Why? You skipping school?”

“Yeah, I’m skipping. I feel awful, and I don’t want to go home.”

“You can’t keep this up forever. No matter how bad your behavior is, if you’re gone for days, your mom will file a missing person report.”

Her aura showed the blue of 【Relief】【Calm】 and the gray of 【Sadness】【Pain】. There was also a hint of the white of 【Acceptance】【Trust】.

Did yesterday’s interaction change how she sees me?

Honestly, I have no idea what part of it made her trust me. Or perhaps, at this point in time, she already trusted me to some extent?

“I don’t want to go back.”

“Tch, do whatever you want. But I’m telling your mom you’re staying here.”

“Hmph! Do what you want!”

With that, Ayano pulled the blanket over her head. Turning her back to me in a sulky huff, she settled into the sofa as if to sleep. Once she’s like this, there’s no point in saying anything. I’m starting to get it—this is probably Ayano’s way of shutting people out.

“I’ll leave the door unlocked. If you’re hungry, rummage through the fridge.”

I was ready for school.

After telling Ayano that, I left the house.

I was admittedly concerned about her, but my first high school day in sixteen years awaited. For the rest of my life, I’d have to at least pretend to be a normal person on the surface.

My mind was entirely preoccupied with that thought.