That time I got reincarnated into Attack on Titan with a level up system

4. E-rank Dungeon

I inserted the key into the lock of the underground city's entrance. The moment the key clicked into place, a soft hum filled the air, and the door before me shimmered, revealing a glowing passageway that seemed to pulse with energy.

"So, this is a gate," I muttered, stepping back to take it all in. "An E-rank one." My mind raced with comparisons to the video games I used to play. In those games, difficulty levels often ranged from E-rank being the easiest to higher ranks offering progressively tougher challenges. But this wasn't a game, and underestimating this dungeon could be a fatal mistake.

Summoning every ounce of courage, I took a deep breath and stepped through the passageway. The air around me shifted, cool and damp as I descended the staircase leading to the underground city.

The stairs wound down for what felt like an eternity, the walls narrowing around me, and the only sound was the faint echo of my footsteps. I couldn't help but feel a shiver of anticipation mixed with anxiety. Finally, after several minutes of descent, the passageway opened up into the vast expanse of the underground city.

But something was off—there wasn't a single soul in sight. The city was eerily silent, its usually bustling streets now empty. The dim, flickering lights cast long shadows across the cobblestone streets, but no movement disturbed the stillness.

I had heard stories of the underground city, a haven for criminals, outcasts, and those who preferred to live in the shadows of society. But this version of the city was devoid of life. It was as if everyone had simply vanished.

"Where is everyone?" I whispered to myself, my voice echoing slightly in the empty space. On one hand, I was relieved not to have to deal with the dangers of the city's usual inhabitants. But on the other, the emptiness was unnerving. Had the system created a copy of the underground city just for this dungeon? Or was I somehow in a different dimension, a parallel version of the AOT world?

My mind buzzed with questions, but I pushed them aside for now. There would be time for answers later—first, I had to navigate this place.

"Inventory," I said, and the familiar interface appeared before me. I quickly scanned through the items I had on hand. Besides the bread I had stored earlier, it seemed I had retained all the possessions I had with me from my previous world, right before the truck hit me.

There was my phone, though it was useless here without service. I sighed, but at least I had something familiar with me.

And then single plastic bottle of water caught my eye—thankfully, I wouldn't have to worry about dehydration while exploring this dungeon.

I also noticed a solar-powered battery bank with a charging cable. I couldn't remember when I had packed that, but considering the offline games on my phone, it might come in handy for entertainment after this was over.

My backpack was also present, filled with textbooks and a few novels I had been reading. They seemed out of place here, but the familiarity was oddly comforting.

However, it was the last item in the inventory that really caught my attention: a standard sword.

"I definitely didn't have this in my previous life," I mused, pulling the sword out from the inventory. It was plain but well-crafted, the blade gleaming faintly in the dim light. The weight felt right in my hand, balanced and reassuring.

"Is this from the system?" I wondered aloud. Regardless of where it came from, I was glad to have it. Facing whatever lay ahead empty-handed would have been reckless.

"Close Inventory," I commanded, and the interface blinked out of existence. With the sword in hand, I started to walk forward, deeper into the underground city.