(POV will be Wilhelm until stated otherwise, or it's incredibly obviously not Wilhelm, and I forgot to mention it. Also, I did actually create a different measurement system; I am not pulling measurements out of my ass.)
I hit the ground sharply; it doesn't hurt, but it does let me know that I'm out.
Out of that... abyss.
My breath comes shakily.
I never knew just how much I took this air for granted.
Swiftly placing Heidi on the ground next to me, I place a finger to her neck. Her heart rate has spiked.
Looking up at the dungeon gate, I shakily raise a hand and cast barrier magic several times over the entrance.
I'm not going to let any poor soul who passes by enter that abyss, unless they're strong enough to get through these.
And, when this dungeon breaks, these should stall them.
From what I gathered from that encounter, the dwellers of this abyss use barrages of weak attacks to overwhelm defenses. So, I modify the walls to be weaker against massive attacks, but regenerate rapidly against small attacks.
I can only hope that I'm right.
I would have spent days here, forging a wall that would take A-rank adventurers actual effort to get through, but I must get Heidi to a priest.
With swiftness but carefulness, I pick up Heidi and dash off towards the closest major city.
Within a few minutes, I can already see the city. Walls of stone, several stretches tall and several spans thick. Every few marks, a rune of some sort is etched into the stone. Houses, stores, and restaurants line the streets. Children frolic without a care as their parents watch fondly. Fellow adventurers line the walls and patrol the streets, most E or D-rank.
I leap from a small hill, using it as a ramp to launch myself over the walls.
The runes flare briefly before recognizing me and deactivating.
I land with a sharp bang, cracking the street beneath my feet before launching myself once again down the street.
I barrel through a market district, carefully avoiding citizens as I maneuver.
After several dashes and launches, I come skidding to a stop in front of the church.
Even my status as a B-rank adventurer doesn't let me barge in.
I look down at the child in my arms. She's still breathing.
I sigh in relief as I walk up the stairs. I've made it.
I knock on the massive wooden doors, the sound echoing.
A few moments later, one of the doors creaks open. An old man poking his head out.
"Ah! Wilhelm, it's been so very long since you've come to visit. Come in, come in."
The old man turns to walk back inside.
"Priest Ludwig, I need your help. It is urgent, terribly urgent."
Ludwig pauses and turns back, slight shock on his face.
"For you to call me by my title, it must be truly urgent. What is it?"
I silently present Heidi to him.
Ludwig takes one look at Heidi, not even a hint of recognition in his eyes, but they fill with urgency nonetheless.
With a flick of his wrist, the church doors open fully, allowing easy access.
"Follow."
I silently follow him through to the back of the church, passing holy images, texts, and half-written sermons.
Reaching a small medical area, Ludwig silently gestures at a bed.
Seeing this, I place Heidi on the bed, and Ludwig immediately begins to use detection magic on her.
"By the voice of El... I haven't seen mana exhaustion this bad in hundreds of rotations."
Lifting one of his hands, Ludwig briefly scans me as well.
"You've got it pretty bad, too. What happened?"
I'm silent for several moments, my mind still racing, trying to make sense of what I've witnessed.
I see Ludwig turn to me in my peripheral vision. "Wilhelm?"
"I witnessed an abyss, Ludwig. I entered an E-rank dungeon to protect this little one on her first dungeon dive." I gesture at Heidi. "I know you don't care much for politics, so I'll tell you who this is. This is Heidi, the daughter of her grace Hanna."
Ludwig doesn't respond, simply listening while examining Heidi.
"When I entered, I couldn't breathe. I inhaled and got air. Nothing more, nothing less. There wasn't any mana, not even a speck or faint residue. And it was loud, bright, and disorienting all at the same time. Dozens, maybe hundreds of sounds I can't describe impacted me all at once, lights of different colors blinded me. My mind was foggy, refusing to work properly."
I take a deep breath, trying to stabilize my breathing.
"There were golems with odd weapons and lesser mimics in white robes. For reasons I can't understand, they didn't attack me instantly. Instead, the lesser mimics backed away while the golems defended them. They only attacked once I used magic to defend Heidi."
In a calm, almost soothing voice, Ludwig responds. "Go on."
"I don't know how to. There were monoliths of steel that stretched into the clouds and things flying across the sky at great speed. Without wings or magic."
After a few moments, I speak again. "Now that my mind isn't as hazy, I remember the faint buzz of lightning. Do they use untraceable lightning magic?"
"Well, I'll let you ponder that while I treat this child. Go and figure out how to report too Miss Hanna that you've injured her daughter."
I just sigh. "That's what I'm trying."
"Then try somewhere else, I need focus."
And so, I walk out of the church and silently sit on the stairs.
"...ok. What do I know for certain? Well, there was no mana for one. There were lesser mimics and golems. Wait, no, there was no mana. Golems require mana to function. Was it armor then? What sort of armor is it then? What monsters would wear that kind of armor...? Mimics? They can scavenge equipment after all. But I've never seen that type of equipment before..."
I sit there, lost in thought for several moments.
"What if... those weren't mimics...? Mimics aren't typically that small unless they're newborns, but newborns can't shapeshift yet. Unless they're a new species of mimic, those couldn't have been mimics. Also, mimics need to see something to transform into it. Those cannot be mimics. So, they're a new species of monster."
"Why'd they resemble us so closely then? A new type of goblin? Goblins do resemble us somewhat. But goblins attack on sight. Plus, they don't use armor. An evolved form of hobgoblin? They're roughly the same size. But hobgoblins are even more aggressive; the behavior doesn't match."
"Alright, let's focus on species later. What types do they have? Soldiers, obviously. But what of the white ones? They reacted like... civilians? Why would a dungeon have civilians? In the hostile ecosystem of dungeons, civilians don't exist. The closest thing would be non-combatants who help combat in other ways. Is that what they are? But monsters don't react with fear like that when warriors are right there."
I silently lay down on the steps.
"Even ignoring the monsters themselves, what of the monoliths of steel? What purpose do those serve? Dwelling? The only thing I know of that makes dwellings that large compared to their size are ants. Are they a hivemind? Were the ones in white workers? No, that doesn't make sense; hiveminds use magic to project orders to multiple monsters across distance. There is no natural mana over there."
"All of that is ignoring the flying objects. I'm not even going to try with that. Wait, speaking of the impossible, how did they break my barriers? They don't have magic, and bows can't do that level of damage, or hit that fast without thousands of archers. The steel monoliths would have prevented that many archers from shooting at once."
I slowly sit up and stand. "I'll figure this out on the way."
And so, I begin my journey to explaining to a duchess that her daughter has been severely harmed under my watch.