Fabre in Sacheon's Tang

The first thing that caught my eye was the ominous message about vengeance.

But for Sister Seol and Hwa-eun, something else stood out.

There were martial arts inscriptions and written texts etched into the stone walls.

"This...!"

"It's the Five Poisons Returning to the Origin Art (O-dok-gwi-won-shin-gong) technique manual, So-ryong!"

"Why is this here...?"

"This is the martial art you've been practicing?"

Hwa-eun was right. The inscriptions were unmistakably the martial art I had been learning—complete with training instructions and guiding principles.

At first, I was excited, thinking this could help refine my techniques.

But as I read further—

I stumbled upon something insane.

"Once you have reached the Eleventh Stage of Five Poisons Mastery, you must behead the five venomous creatures you have bonded with, drink their blood, and boil their bodies with ginseng, angelica root, and poria mushroom for three days before consuming the elixir. Only then will you fully master the Five Poisons Returning to the Origin Art."

'These people were completely insane.'

Since this technique was based on Beast Heart Arts, it naturally required a strong bond between the practitioner and their venomous creatures.

But now, at the peak of their training, they were expected to murder their own bonded creatures, drink their blood, and boil them down into medicine?

No wonder these lunatics were wiped out.

"Hwa-eun, lend me your lantern."

"My lantern? Why?"

I took the lantern from her hands, pulled out the oil wick, and burned the twisted passage immediately.

I made sure it was completely unreadable—reduced to nothing but blackened soot.

Flames flickered, consuming the depraved inscription, leaving behind only charred rock.

Sure, I had eaten snakes and scorpions for survival in Hainan.

But those were wild creatures, not companions I had bonded with.

These people were raising venomous creatures only to slaughter them in a deranged ritual, as if they were brewing some dark sorcery.

‘Telling me to kill my daughters, drink their blood, and eat them boiled like some demonic cult? Absolutely not.’

I had no regrets about destroying that part of the manual.

The moment I stepped back, Hwa-eun and Sister Seol both patted me on the shoulder.

"Good job, So-ryong."

"Yeah, that's my little brother."

And only now did they seem to notice the blood-red message I had seen earlier.

Hwa-eun narrowed her eyes.

"This confirms it—there were definitely survivors from the Five Poison Clan."

"I was thinking the same. Hwa-eun, this message... it's written in blood, isn’t it?"

This was clear evidence.

Whoever had been trapped on the other side of this tunnel had vowed revenge on those who abandoned them.

"We need to be careful from here on."

"Yeah. Also... judging by this message, it looks like the exit can only be opened from the other side."

"That makes sense..."

After thoroughly inspecting the area, Hwa-eun sighed.

"I was hoping to study the mechanism, but it looks like it's impossible to activate it from this side. The real mechanism must be hidden somewhere on the opposite end."

She looked genuinely disappointed.

Clearly, she had wanted to figure out how the hidden door worked, but there was nothing left to examine.

The Five Poison Clan must have deliberately concealed the control mechanisms.

"In that case, we have no choice but to keep moving forward," Sister Seol said. "This passage looks abandoned, but we should still stay alert."

"Agreed, let's go."

With that, we pressed on.

But we didn’t get far before we were forced to stop.

In front of us—

A ten-meter-deep vertical chasm blocked our path.

So that was why the martial arts manual had been written on the wall.

This space was effectively a sealed chamber—

Impossible to climb up from the other side, making it the perfect trap for anyone who entered.

Using Yo-hwa and Cho, we carefully descended into the chasm.

But just as we landed, Hwa-eun suddenly grabbed my arm.

"So-ryong, something about this cave feels off."

"You're right... this tunnel is strange."

I took a closer look.

The moment we reached the bottom, I realized what she meant.

The natural rock formations we had seen earlier were gone.

Instead, the tunnel stretching ahead had a perfectly round shape—

About three meters in diameter, forming a smooth corridor.

It looked too artificial to be a natural cave.

Yet, it wasn’t entirely man-made either.

"This isn't normal..."

Hwa-eun and Sister Seol both ran their hands along the walls.

Instead of rough rock or soil, the cave walls felt smooth and hardened.

Not like something that had been carved out—

But something that had been melted through.

"It's almost like... the stone was liquefied."

Their voices carried unease as they examined the cave walls.

A strange wave-like pattern rippled across the surface—

As if the rock had once flowed before solidifying again.

And something about it felt familiar.

‘Where have I seen this before...?’

I knelt down and touched the ground.

The surface felt solid, yet strangely soft beneath my fingers.

Taking out a throwing knife, I carefully scraped the floor—

And sure enough, the stone was just soft enough to be marked.

Then it hit me—

A memory from my previous life.

A place I had once visited as a tourist.

‘Wait a minute. This looks exactly like—’

The Cu Chi Tunnels.

The underground network used by Viet Cong soldiers in the Vietnam War.

I had once toured those very tunnels, and the soil there was exactly the same.

‘The guide said Vietnam had limestone-rich clay—soft enough to dig through, but hardening like concrete once dried...’

That was why the Cu Chi Tunnels didn’t need wooden supports—

And this place felt just like it.

Which made sense, considering...

"We're near the Yunnan-Vietnam border."

Hwa-eun's eyes widened.

"Wait... so this was dug by humans?"

Sister Seol looked skeptical.

"But... how would they even dig this deep?"

I smirked.

"Remember, martial artists are basically superhuman construction workers. With their strength, they probably didn’t need thousands of people. A few dozen highly skilled warriors could’ve done this."

If the Viet Cong had dug 250 kilometers of tunnels with sheer manpower—

Then a dozen martial artists could easily dig something like this.

Hwa-eun crossed her arms.

"If this really is a man-made tunnel, that means... it could be much longer than we think."

Sister Seol scoffed.

"Come on. How long could it possibly be?"

I simply smiled.

"Let’s find out."

Hours later—

The three of us trudged through the endless tunnel, exhausted.

Our initial excitement had long since faded.

[Seol, I think our ancestors were insane.]

[Agreed. This is not normal.]

At this rate—

We were seriously about to hit 200 kilometers.

***