The size of the region over which the ruins spanned was enormous. It exceeded the size of the Town of Hajin and the Capital Town of Vargard in the Kandrian Empire. It was clearly extremely. Buildings had been chopped right down to their very foundations, leaving only the sturdy bases that once supported them.

Piles of rubble from bricks and slabs of stone piled up across the entire region, painting the desolate picture of the erosion of civilization.

Yet, not even time could hide how glorious this city would have been in during its prime. The network of roads indicated an incredibly brilliant vision of civil engineering for the entire metropolis. The foundations and bases of infrastructure revealed an extremely well-thought-out planning for infrastructure allocation.

Just these clues alone allowed one to infer that this was far from a primitive civilization that merely tried to survive.

No.

This was a civilization that thrived.

It was a painful reminder that nothing could last forever.

"How can this be…?" Kane gazed at the ruins with shock. "These aren't years old. Or even decades old. These are centuries old, if not longer! But how? Weren't we much more primitive back then or something? We barely survived outside of the Beast Domain that spanned much of the continent. How in the world did a human city flourish in the Beast Domain?!"

He grew excited. "We need to inform the Adventurer's Guild about this place!"

"They already know," Rui replied calmly. "They have taken to calling it the Lost City of Nagarojin."

Kane's eyes widened with surprise. "Lost City of Nagarojin?"

"Yeah," Rui nodded. "This is the name designated to this particular lost city."

"Wait wait wait," Kane raised his hands, gesturing Rui to stop. "Isn't this revolutionary?! Why are you so nonchalant about it?"

"It is revolutionary," Rui nodded. "But it is not new. It isn't even unique. There are other such ruins in the Beast Domain, although very scarce and rare. It is not possible for ruins from well beyond the age of Martial Art to survive this long."

"…What?" Kane whispered, turning back to the lost city. "I don't get it. How can that be? What does it even mean?!"

"The mystery of lost cities is one of the greatest mysteries we know," Rui replied. "Lots of data has been collected throughout the years on these strange ruins of civilization in the Beast Domain, and the very cream of the crop of experts and scholars of human civilization have collectively gone through it to try and piece together the very mystery that plagues you right now?"

"…And…?" Kane urged him.

Rui shrugged. "Nobody knows. Nobody understands how human civilization existed in the Beast Domain. It has utterly baffled archaeologists, anthropologists, historians, and other experts in relevant parallel fields."

"Oh, come on!" Kane complained. "You can't leave hanging like that!"

Rui smiled wryly, amused. "Well, there are hypotheses. Of course. However, none of them have managed to cross the threshold to be considered as fact beyond a reasonable doubt. It is one of the greatest points of conflict among historians specializing in early humanity."

STEP

The two of them reached and landed in the metropolis of ruins overrun by thick vegetation. Yet, no amount of vegetation could hide the touch of humanity in this particular region.

Rui's senses washed over the entire region, relieved at what he sensed.

"Well, this seems to be most an Apprentice-level danger zone," Rui heaved a sigh of relief. "Considering that the bases of these ruins and all this light vegetation are intact, I highly doubt there are any Master-level monsters in this particular region. We can take a break here, get some rest and recuperate."

"What hypotheses?" Kane urged, ignoring his words.

Rui smiled wryly. "First, we find a good place to get some rest."

The two of them tread through the ruins of the Lost City of Nagarojin, observing the various remains of the ruins.

Not much could be inferred due to how much had been eroded by time.

Patched of what used to once have been a road appeared to be constructed by burying slabs of stone into the mud beside each other to form a level path. Considering even a bit of it had managed to survive centuries in the Beast Domain, its endurance could be praised.

"Woah…" Kane murmured as he came across an open space in the ground with straight walls. Something that, once, was clearly manmade. "You think this was like an open bath or a swimming pool of ancient times?" This is from .

Rui shrugged, eying a particular spot. "I found us a good spot."

He gestured towards a particular ruin in the distance whose walls were better preserved than any other. Creepers had formed a net atop it, allowing it to serve as a natural shelter. The two young men decided to partake in its shelter for the time being, having traveled more than a day continuously.

"Alright, spit it out," Kane glared at Rui, who enjoyed his impatience.

"I told you," Rui replied, drinking some water. "Nobody knows. There are only hypotheses. One popular hypothesis is the Beast Nativity Hypothesis, which states that human civilization long ago had been integrated into the Beast Domain along with the fantastical fauna and flora of the Beast Domain. This particular hypothesis suggests that the Beast Domain once covered every end of the Panama Continent, and humans lived within it as just one out of many species of the Beast Domain."

"Woah," Kane murmured as his gaze returned to the lost city around him. "That would explain why there was a human city or multiple human cities in the Beast Domain. But that feels off, to be honest."

Rui nodded. "Occam's Razor certainly aids this particular hypothesis due to how simply it follows the evidence. However, there are many gaping questions that present themselves at the behest of this particular hypothesis. What happened? The earliest human records preserved in the Human Domain indicate that humanity was outside the Beast Domain on the very outskirts of the Panama Continent. So how and why did humanity go from inside all the way outside, abandoning the robust and sophisticated civilization that they built in the Beast Domain?"

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