Did the Great Slime (+3) already wipe out all of the Slimes as it passed by? It was so silent that his noisy fight earlier with the Great Slime felt like a fever dream.

And it’s too clean here. Ah, was all the filth melted by the acid?

A Slime’s acid would become more potent after it evolves into a Great Slime. It would melt solids and evaporate liquids; it was only natural for the sewers to become this clean after a Slime spewing such horrific acid had crawled through them. That, however, begged the question of why the passageway was completely intact.

I know it’s far-fetched, but for the sewer system to accommodate the Slimes so well… It’s almost as if the Slimes are meant to be here.

He wondered what the Empire had looked like while it was prosperous, and he couldn’t get the thought out of his head. He might never find the answer to his question… A wistful smile would’ve tugged at his lips if he had lips. He went back to exploring the sewers.

"...Hmm?"

There was an indent on the left passageway, which, upon closer inspection, was a square that would comfortably fit the palm of his hand. He found traces of hidden mana at its center. It felt extremely old.

Is this perhaps...

This looks like those fingerprint scanners in movies. Lee Shin-Woo didn’t ponder for long before placing his hand on the square. To his surprise, the square began to glow and protrude out of the wall. Beyond any doubt, it was...