The Multi-Legged Walker Prototype 1 (WP1) drove stakes from the tips of its six legs into the ground, anchoring itself securely. It then deftly manipulated its work arms, deploying a geological survey drill and sampling apparatus.

The three WP1 units were conducting geological surveys at the fortress construction site. For areas where underground structures were planned, deeper vertical shafts would need to be excavated for assessment. However, for temporary warehouses, basic airstrips, or road construction, the WP1’s lightweight drilling and boring equipment sufficed. Two units focused on drilling while the third assisted with sample collection. The retrieved samples were currently being stockpiled along the coastline, awaiting transport to the construction ship once the pier connection was complete.

The blackened, barren ground, devoid of vegetation, was dotted with these gleaming silver machines. Their busy movements and constantly working arms gave a somewhat comedic impression—from a distance, at least.

Up close, however, their sheer size—4 meters tall and over 10 meters wide and long—would likely evoke a primal fear. Their eerily smooth, almost organic movements heightened this effect. For now, the noise of the gas turbine engines powering them added an audible reminder of their mechanical nature, but once they were retrofitted with the quieter microwave power system, they would become even more unnerving.

“So, you said there’s something unusual?”

“Yes, ma’am,” Ringo responded.

Eve had been quietly watching the WP1 units at work, but the reminder prompted her to turn her attention back to the report.

“During the drilling surveys, we’ve identified layers of tunnel-like structures intersecting the strata. These tunnels range in diameter from a few centimeters to several dozen centimeters. These formations are not consistent with natural geological phenomena, so they are likely the result of biological activity.”

“...In solid volcanic rock?”

“Yes, ma’am.”

“Just to confirm, the rock isn’t unusually brittle, is it?”

“No, ma’am. It’s standard volcanic rock. While there are regions with pumice-like structures, it’s still solid rock.”

“...So, we’re dealing with another absurdly powerful creature?”

“Unknown, but it’s highly possible.”

Eve frowned, contemplating the situation. If Ringo found it noteworthy enough to report, it likely wasn’t something trivial. At the same time, the fact that Ringo framed it as a general report suggested it wasn’t an immediate threat. They could simply monitor the situation, but Eve had a nagging feeling that leaving it unchecked could lead to trouble.

“I don’t know… Something about this feels like we shouldn’t ignore it.”

“Agreed, ma’am. Some form of action is likely necessary, though we lack precedent for dealing with such phenomena.”

“Well, if even Ringo is unsure, I suppose that’s fair. It’s not exactly in your programming to deal with fantasy monsters.”

Ringo was an exceptionally capable AI, but its experience was rooted in the realm of science fiction. When confronted with phenomena that seemed more like fantasy, it was understandable for the AI to struggle. Even Eve, with her broader exposure to fantastical stories and games, couldn’t imagine a clear solution.

“Solid volcanic rock riddled with unnatural tunnels… What’s our next step?”

Eve voiced her thoughts aloud. Identifying the cause—most likely some sort of magical creature—seemed like the only viable option.

“What kinds of creatures could create such tunnels?”

“Based on known biology, subterranean animals include large mammals like moles or certain rodents, as well as smaller creatures like ants, insects, arthropods, or worms. Microorganisms are also capable of interacting with geological strata, though they are too small to account for these tunnels.”

“Hmm… So, on the surface, something like moles or rodents?”

“Yes, ma’am. However, mammals would require a supporting ecosystem of plants, fungi, insects, or other organisms for sustenance.”

“Oh, right. Food supply is essential.”

Food was indeed critical, but no biological traces had been identified in the initial samples.

“So far, we’ve found no evidence of an ecosystem within the volcanic layers. The initial sample surveys showed no biological traces.”

“I see… That rules out conventional organisms. So, what, a magical, non-scientific lifeform?”

“That would be beyond our understanding, ma’am. Without foundational knowledge, speculation is difficult.”

“That’s fair,” Eve muttered. You can’t get something from nothing. To address the unknown, they would need new information.

“Perhaps we should conduct some local inquiries in Telek Harbor. Since the volcanic layer extends across the Afurasia United Kingdom, there might be similar findings elsewhere.”

Ringo set about discreetly gathering information in Telek Harbor. After a few days, the results were in.

“Ma’am, we’ve gathered information about subterranean monsters.”

“...Monsters?”

“Yes, ma’am.”

Monsters. While Eve had encountered Rain Croix, this was the first time she’d heard a local term directly referring to such creatures.

“Alright, tell me.”

“The creature is called a ‘Ground Worm.’ Scientific classifications are undeveloped, so local descriptions are unreliable. Ground Worms live underground but occasionally surface, and they’re known for being extremely aggressive. Smaller ones are said to be finger-sized, while larger ones—according to legend—can grow taller than mountains. The best advice upon encountering one is to flee. If attacked from below, it’s suggested to… give up.”

“Worms… huh.”

The term conjured images of long, worm-like creatures. While nuances might differ between languages, Ringo’s translation was typically accurate.

“So these Ground Worms are digging through the volcanic layers?”

“Yes, ma’am. Based on reports, their habitats are localized rather than widespread. However, the current survey area likely overlaps with their territory.”

That was not the news she wanted to hear. Abandoning the area and finding a new site was an option, but with the pier already under construction, such a move would be costly.

“Can they be eliminated? Or, if not, can we coexist with them somehow?”

“That remains unclear. Most accounts are anecdotal. Interestingly, there are few sightings near Telek Harbor, Iron Town, or major roads. It seems we’ve drawn the short straw.”

“Don’t call it the ‘short straw,’ please.”

Whether by bad luck or geography, they had entered Ground Worm territory. Further investigation was inevitable.

“There are conflicting reports about their durability. Some say they’ve been cut down with swords, while others claim swords bounced off. This suggests significant variation in toughness between individuals.”

If Ringo concluded that, it was likely correct. At least this implied they weren’t all as absurdly tough as Rain Croix.

“Still, we can’t afford to be unprepared. Identify sampling points, deploy WP1 units, and start surveys. Maybe we should design a specialized investigation model.”

“Yes, ma’am. For mapping the hollow distributions, we’ll equip the units with sonic detection systems. However, this might provoke the Ground Worms or other creatures.”

“Hmm. We’ll have to factor in losses. Deploy teams in pairs, and include Alpha-Class ships as mother vessels for support.”

“Yes, ma’am. I’ll begin construction immediately.”