The balloon Otani-san hit with his Fireball vanished, leaving behind nothing but a tiny smear of charred, melted rubber. The Fireball seemed to have carried incredible heat, as the ground where the target had stood was now scorched a dark, brownish-black. I wondered if a direct hit from that would be enough to take down a monster from around the 10th floor in a single blow.
During the introductions, he had been modest about his background as an explorer, but it seemed his proficiency with magic skills was quite high. Then again, magic at level zero proficiency—the state right after acquiring a skill—would lack the power necessary for an official inspection, so his competence was to be expected.
"That was the first time I've ever seen magic in person... it's nothing short of incredible. To think you can conjure a ball of fire like that with just a single word..."
Yuta-san stared dazed at the impact site, his voice a mixture of fear and envy.
"Oh? Was that really your first time seeing magic, Yuta-san?"
"Ah, yes. By the time the dungeons were opened to the public, I was already working at my current firm. Ever since the opening, the dungeon boom has kept us so busy that I've only ever seen footage on TV specials."
"I see. It is true that ordinary people without an Armed Exploration Permit for Special Underground Structures rarely have the chance to witness magic skills firsthand. The Association's training facilities that allow skill use are generally off-limits to anyone without a permit."
"I’d heard rumors that explorers would pay exorbitant sums for magic skills, and seeing this, I think I understand why. Putting practicality aside... if you could suddenly use something that was a mere fairy tale until recently, it’s only natural to want it."
Kawakita-san nodded understandingly at Yuta-san's reaction, while Yuta-san directed a gaze of longing toward Otani-san.
Actually, we could use magic too, though I realized we had never shown Yuta-san. Of course, using it in an unauthorized location could get us arrested at worst, so it made sense that we had kept it under wraps.
"Good work, Otani-san. The ground is a bit scorched, but there don't seem to be any issues like subsidence."
"Fire Magic primarily burns the target, so it tends to have a low impact on the surrounding environment."
"Right. Then I'll be next."
"Understood. Wait a moment while I set the next target."
Yaguchi was up next. Otani-san headed out to set up another balloon. Once he returned, Yaguchi stepped forward and raised her right arm straight up.
"Wind Cutter!"
As she shouted the command and swung her arm down toward the target, an invisible blade of wind manifested, distorting the air as it streaked forward. The Wind Cutter flew at nearly twice the speed of the Fireball.
It sliced through the balloon and slammed into the ground with its momentum intact, carving a deep gash into the earth. It was impressively sharp. Like Otani-san, Yaguchi clearly had high proficiency with her skills.
"...That looks safe. The ground isn't so brittle that it'll be pierced through."
"The Great Cavern below is supposed to be several meters deep even at its shallowest point. Attacks without mass shouldn't cause any problems."
"True. I just hope the magic skills with physical mass don't cause any issues."
"Yeah, me too."
Yaguchi finished her attack and observed the mark on the ground while discussing the next step with Otani-san. Indeed, the fire and wind magic they had used so far carried little mass and were types of offensive magic that rarely affected the structural surroundings.
It seemed those first few spells were just to gauge the situation; the main event was about to begin.
Watching the exchange between the two inspectors, Yuta-san asked Kawakita-san about something that had piqued his interest.
"Judging by their conversation, were those previous spells just a preliminary test?"
"Yes. It follows our standard procedure for gauging environmental impact. We start with low-impact magic to conduct a preliminary Impact Survey, and only then move on to magic that might cause a greater reaction. It’s a safety protocol."
"Low impact... really?"
"Indeed. In this case, since there is an underground cave but few combustibles in the area, the cutting force of wind is considered low impact. That's why fire and wind—magic with little mass—were used first."
Yuta-san looked satisfied with Kawakita-san's explanation, though he still cast a worried glance toward the inspectors. I understood his concern, but it would probably be fine. The magic Otani-san and Yaguchi had used wasn't the type to generate massive explosive pressure. They were being cautious, so I didn't think the ceiling of the cavern would suddenly collapse. Though, I wasn't sure what would happen if someone kept spamming spells in the same spot.
While we talked, the preparations were completed. Now for the high-impact magic.
"Water Ball!"
At Otani-san's shout, a sphere of water the size of a volleyball formed at his palm and shot forward at roughly the same speed as his Fireball. Given its size, it was a mass of water that likely weighed tens of kilograms.
The Water Ball struck and destroyed the balloon before slamming into the ground. The sphere burst, drenching the impact site and lightly gouging the surface. A significant amount of water flowed into the crack Yaguchi had carved with her Wind Cutter, turning a wide area of the ground into a muddy mess.
"That seems fine too. Your turn, Yaguchi-san."
"Right. This works perfectly. Even without a balloon, the wet ground makes the target point very easy to see."
Yaguchi faced the target area, spreading her legs slightly like a pitcher and drawing her right hand back with the palm open.
"Stone Bullet... go!"
A pointed mass of stone the size of a 500ml bottle formed above her palm. Following the swing of her arm, she launched it at the darkened, wet ground. Its speed was somewhere between the Fireball and the Wind Cutter.
The moment the Stone Bullet struck, it let out a roar, violently blowing away the mud softened by the Water Ball and creating a small crater.
"Whoa..."
A gasp of shock escaped Yuta-san's lips.
Compared to the previous attacks, this one had caused a spectacular amount of visible damage. The deepest part of the tear-shaped crater was gouged out by about a meter.
"Even with the prep work, that really sent the dirt flying."
"There should still be plenty of distance to the cave ceiling, but... is it okay?"
"I think... it'll be fine. It looks like a lot, but most of what blew away was just the muddy topsoil. I don't think it's affected the cavern's integrity."
The three of us stared at the crater with slightly worried expressions, trying to estimate the impact on the cave below. Kawakita-san, Nohara-san, and Yuta-san seemed too fixated on the crater itself to think that far ahead.
After a few moments of observing the crater, Otani-san and Yaguchi beckoned us over.
"Everyone, please come take a look!"
Reacting to the call, Yuta-san and the others snapped out of their shock. With slightly sheepish looks, they signaled for us to follow them to the site. We nodded and walked over to where the inspectors were standing.
"Good work, Otani-san, Yaguchi-san. How was the live-firing test?" Yuta-san asked on behalf of the group, his voice tinged with worry. Looking at that deep hole, he was clearly anxious.
Otani-san gave a small smile and pointed into the crater.
"Look here. It looks like a large crater, but it's mostly just the muddied soil that was blown away. Even at its deepest point, it hasn't reached the bedrock, so I believe there are no practical issues. Of course, this is just a visual assessment; I'll provide the detailed measurement results later."
"I see. Thank you. When I saw that huge hole, I was worried the ceiling might cave in. I'm relieved to hear it's likely okay."
"I'm sorry for the scare. However, we won't know the final result until we've finished the rest of the survey. Sometimes things look fine but the measurements say otherwise..."
"Of course, I understand that."
With the assurance that it was probably fine, the tension left Yuta-san's body. If the live-firing test had failed, the plan for a skill-compliant training ground would have died right here. We still had to wait for the official results, but it felt like we'd cleared the biggest hurdle.
Once the magic test was over, Kawakita-san and the others used various instruments to measure the area around the crater. While the final analysis would come later, their expressions didn't look particularly grim as they finished.
After we all helped lightly level the disturbed ground, we finally headed to the last inspection site: the underground cave.
"I’ve heard rumors about a massive cavern down here... something truly spectacular."
"Spectacular, huh? I don't know if it'll move you, but it definitely makes you feel the power of nature. It's the kind of place that makes you realize just what nature is capable of creating."
Otani-san looked genuinely excited, a grin on his face as he anticipated the cavern. Men never really outgrow the sense of romance that comes with the phrase "underground cave." It seemed Otani-san was firmly in the pro-romance camp.
"That does sound intriguing. But is it really safe to descend into a cave that hasn't been developed?"
"It's dark and the footing is treacherous, but the risk of a sudden collapse is low. It was surveyed by specialists when it was first discovered."
"I see..."
At Yuta-san's response, Yaguchi's expression clouded with anxiety. She closed her eyes for a second, then opened them with a look of grim determination.
I wondered if Yaguchi had suffered some kind of trauma in a dungeon. To have two high-proficiency magic skills and yet quit being an explorer to work as a clerk for the Dungeon Association... No, it would be tactless to pry when she hadn't said anything.
"Um, Yaguchi-san? If you're not comfortable with underground caves, would you like to stay up here with me while the others go down?" Hiiragi-san suggested softly.
"...Thank you. But I'll be fine."
"I see..."
Yaguchi shook her head, her face pale but set. The three men from the Association watched her with unreadable expressions, quietly respecting her resolve.
"Yaguchi-san, if it gets to be too much, please just say so," Kawakita-san added. He seemed to know the circumstances, but her answer remained the same.
In a situation like this, there wasn't much an outsider could do. I just hoped she wouldn't force herself too hard.
In a somewhat heavy atmosphere, we arrived at the entrance to the underground cave.