What If the Strongest Villain from the Original Story Became the Protagonist's Ally?

After walking through the depths of the dungeon for a while, I eventually emerged into an open area.

There, multiple gray-robed suspicious figures were present.

“…? Who are you?”

An elderly man who seemed to have a particularly high rank among the gray robes—or at least gave off that atmosphere—noticed me. He was the only one dressed differently. That would certainly draw attention.

I gave the old man a proper response to his words.

“I’m an intruder. Didn’t you hear the report from earlier?”

This was a cave-type dungeon. I thought the sound would have echoed fairly well… but apparently it didn’t reach all the way to the very back.

Then the positioning along the way was completely meaningless… They just placed small fry like in a game.

“An intruder, you say? This is a dungeon. What business do you have here?”

“You’re quite calm. Aren’t you interested in what happened to your comrades along the way?”

“They probably died, right? Otherwise you wouldn’t have made it this far.”

“Heh… you’re surprisingly level-headed.”

Despite having an obvious dangerous person in front of him, the gray-robed old man showed no particular signs of agitation. While holding bottles filled with liquid in both hands, he gazed at a restrained monster.

Now that I thought about it… what was that thing?

It looked like a monster, but its appearance was subtly different from the monsters I knew.

“Well, whatever. Is that monster your pet? It’s quite cute.”

“Hohohoho. That’s right, that’s right. You understand, despite being an intruder.”

The old man laughed cheerfully at having his monster praised.

Like hell it was. That thing was incredibly disgusting.

“This fellow is Experimental Subject Number Eight, born from my experiments! Compared to previous experimental subjects, the base condition is excellent! It’s no exaggeration to say the synthesis experiment has almost completely succeeded.”

“Synthesis experiment?”

I’d heard that term before. In the original story, if I remembered correctly…

“Are you interested? I don’t mind telling someone who understands like you. Researchers want to talk about their achievements, after all.”

“I’d love to hear about it.”

To get as much information as possible from the old man, I deliberately refrained from attacking or anything else.

The other gray robes surrounding us also remained motionless until their leader gave instructions. They just stared at me, frozen in place.

“Then let me lecture you. First, what is a synthesis experiment?”

The old man began his explanation.

“A synthesis experiment is, as the name suggests, an experiment synthesizing monsters together! Of course, once this technology achieves reliable results, we plan to synthesize humans and monsters next.”

“Monster synthesis experiments… huh. That’s the kind of thing a crazy scientist would think of.”

“Human technological advancement progresses thanks to those crazy scientists. You should be grateful.”

“So you’re self-aware…”

This old man was really disgusting. Seriously, synthesis experiments with monsters were showing up at this timing?

In the original story, this setting was supposed to appear in the middle to late stages… but we were still in the early stages. Hell, it wasn’t even the time when the original story was supposed to begin.

“Ahem. Let me get back to the topic. For this synthesis experiment, I tried transplanting cells from multiple monsters into this fellow. Monsters, unlike normal creatures, possess power equivalent to curses.”

“Curses?”

“Haven’t you ever wondered? Why are monsters so strong?”

“That cause… or rather, the source of their power is curses?”

“Indeed. That’s what I hypothesized. Well, it’s just a convenient name—anything would do. The problem is that the curses within monsters spread by invading other cells.”

“Don’t tell me… you’re using that to conduct synthesis experiments?”

“Correct! You’re quite clever.”

Breaking down this man’s explanation in my own terms: monster cells have special effects. They invade all kinds of cells and grant special power—curses.

So what happens when you combine monster cells even between monsters? The strongest cells invade the other cells and become even stronger.

Therefore, if you synthesize monsters, you might be able to artificially create strong individuals. Including the explanation from the original story, it was roughly like this.

To put it more simply: monster cells are too intense. They corrode other cells and grant the host special power. If you increase those cells, you can make monsters stronger! That was the idea.

Eventually they would test it on humans, with the plan of creating intelligent monsters.

Incidentally, human cells were weak compared to monsters. They would definitely be invaded.

As a result, quite tragic incidents occurred in the original story… but more than that, I needed to stop the madman in front of me right now.

“I see… then there’s only one thing I should do.”

“What’s that? Will you join us?”

“Not at all. I’m capturing you here. I won’t let you escape.”

This guy would ruin many people’s lives. So I’d capture him here. Or—kill him.

I drew my sword from its sheath and released killing intent. Then the gray robes surrounding us also readied their weapons.

Finally, the old man said—

“Good grief… so you were a fool after all. To think you can’t understand my research…”

—and proceeded to remove the shackles from the monster behind him.

“In that case, this is perfect. I’ll designate you as a training partner for my experimental subject!”