The beast pen reeked terribly. The Professor covered his mask with an additional layer of cloth as he carefully examined the corpse before him.
It was a camel carcass, its flesh almost entirely devoured, leaving only completely dehydrated bones and dried hide.
Pierced in the neck by a stinger containing paralysis toxin, then stripped clean of flesh by the swarm after death, the information revealed by this corpse matched exactly what the beast keeper had described.
The Professor stood up and looked at the beast keeper. "How often do similar attacks occur? Is there any pattern? Does the swarm always consume every bit of flesh?"
Through these questions, the Professor attempted to deduce the scale of the swarm.
The beast keeper grimaced. "It wasn't so frequent a few months ago, maybe once every week or two. Later on, we'd lose several sheep or camels every week."
The Professor nodded. This wasn't surprising. Vespoids had a short growth cycle, and it was natural for a rapidly expanding swarm to require increasingly more food.
"That's quite a significant loss. Didn't you consider trying to prevent the Vespoids from attacking your livestock?" Erik asked from nearby.
"Of course we thought about it! Though Vespoids are scary, a few people with pitchforks could still handle them. But it's easy to get hurt, isn't it? A shepherd got stabbed in the chest two months ago and almost didn't make it. After that, we didn't dare fight those Vespoids head-on. Later, everyone noticed that when the Vespoids ate their fill from the livestock, they rarely attacked townsfolk. The Elder said to let them eat, better that than people getting hurt. Said we just had to endure until the hunters arrived."
At this point, a smile appeared on the beast keeper's face. "After you all came, those two young hunters have been hunting Vespoids everywhere, so efficient! Now we hardly see any Vespoids around, and the herds are safe. We really owe you our thanks!"
The Professor nodded politely and exchanged a few pleasantries, though inwardly he sighed.
While the gratitude was appreciated, this wasn't yielding any clues.
"Speaking of which, do Vespoids eat anything besides livestock?" Erik asked curiously.
"They do! Sometimes they fly quite far to hunt. You know, there used to be many Cephalos and Delex gathering around here, but they've disappeared over the past few months. Probably got eaten by the Vespoids?"
"Vespoids hunting Cephalos?! That can't be..." Erik muttered.
Cephalos and Delex disappearing? The Professor mentally noted this. "By the way, after those Vespoids kill livestock and eat their fill, where do they fly off to?"
The beast keeper hugged his whip and thought for a moment. "Up?"
The Professor: "..."
Seeming to realize he'd said something useless, the beast keeper quickly added, "They usually come from above. After eating, they look for holes or cracks to crawl into. No idea where they go after that."
"Crawling into rock fissures?" The Professor's glasses gleamed. "Do you know where those fissures are?"
The beast keeper scratched his head. "South, mostly. There are many cracks there. Last time I heard, someone saw a few Vespoids crawling into the furnace waste discharge vent."
—--
By evening, the four investigators gathered at their lodging after splitting up to survey, exchanging the information they'd collected.
Isis was the first to raise her hand. "The pond in the southern part of the cave is warmer! And for some reason, it has a metallic smell!"
Altaïr stared at her blankly. "I can understand detecting high water temperature, but how did you notice the metallic taste?"
"I tasted it."
After two seconds of silence, Altaïr managed to say, "Don't randomly taste things next time. You might get sick."
"South, you say? And temperature?" The Professor seemed particularly interested in these two points Isis mentioned. "Looking at the map, there are indeed more caves on the southern side of the bedrock. As for the temperature, could it be related to the Solar Furnace?"
"I know about this." Altaïr chimed in, recounting everything he witnessed at the Solar Furnace earlier that day. "I specifically asked the Supervisor about the waste disposal cave. He said the only entrance is the waste outlet at the bottom of the Solar Furnace, and the only exit is the discharge port that expels waste from the bedrock. Normally, no one goes down there, which is why there's no information about that cave on the map."
The Professor let out a soft "hmph" upon hearing this. "Coincidentally, I've also heard rumors about Vespoids entering through the furnace's waste discharge port. Combined with the fact that it's an uncharted cave, no wonder we couldn't find it despite searching everywhere."
Smack!
Erik suddenly clapped his hands, startling everyone gathered around the table.
Oblivious to his companions' annoyed glances, Erik exclaimed excitedly, "I knew it! The Vespoid nest must be connected to high temperatures! While not directly relying on the Solar Furnace's heat, the slag and scrap metal dumped into the cave provide sustained warmth. In an enclosed environment, that heat can last remarkably long, even the cold desert nights can't affect it! Perhaps it's precisely that intense heat that caused one of the Vespoids to mutate into a Vespoid Queen!"
"Hmm..."
After pondering for a moment, the Professor suddenly turned to Altaïr. "You mentioned earlier that the Vespoid flew straight into the crucible, correct? And this didn't just happen once or twice, it occurs periodically?"
"Yes, at least according to the Supervisor."
"Considering the Vespoid Queen's size and the scale of the swarm, that cave must be quite spacious," the Professor mused aloud. "The waste slag from smelting alone probably isn't enough to significantly raise the temperature in such a large space. So... could they be directing Vespoids to disrupt the smelting process, forcing large quantities of molten metal to be discarded, thereby heating up the waste cave?"
Altaïr looked at the Professor in astonishment. "Are you suggesting the Vespoid Queen is consciously sending her subordinates to their deaths to 'manufacture' scrap metal and modify their living environment? Can a Vespoid Queen really be that intelligent?"
The Professor shook his head. "It would be far-fetched to say it understands the causal relationships involved. But if we simplify it? When the Solar Furnace activates, the temperature rises, the Queen would sense this. She then sends Vespoids to the mountaintop. Drawn by light and heat, the Vespoids instinctively plunge into the crucible, causing smelting failures. The discarded metal flows into the waste cave, providing precious warmth for the swarm. The Queen doesn't need to know what the Solar Furnace is, nor understand the smelting process. She only needs to associate rising temperatures with dispatching her minions, followed by the arrival of scorching metal. That's sufficient."
"It's the same principle as a baby knowing that crying will bring food to its mouth."
"I have a question!" Isis suddenly raised her hand. "Didn't they say the scrap metal and slag dumped into the waste disposal cavern would slide directly out through the discharge chute? Then how could they possibly use the scrap metal and slag to provide heat?"
The Professor exhaled. "It must be that the Vespoid Queen and her swarm have used some method to block the discharge of metal waste. Since the waste is directly dumped into the sand sea, no one would pay attention to this issue. Wait, didn't that beast handler mention earlier that the Cephalos and Delex that used to wander near the bedrock have disappeared?"
"He did say that," Erik nodded in confirmation.
"Well now, this is getting interesting," the Professor chuckled softly. "Altaïr also mentioned earlier that the Supervisor said some Monsters would be attracted to the discharged slag nearby, that should refer to the Delex and Cephalos. There must be some misunderstanding here. Delex and Cephalos don't have the habit of consuming metal minerals, but many desert insects do, such as the Great Hornfly. The discarded slag attracts insects, the insects attract Delex, and the Delex attract Cephalos. Now that the Vespoid are blocking the slag discharge, the insects no longer come, so the Delex and Cephalos have naturally dispersed."
"So! The disappearance of Delex and Cephalos isn't because they were preyed upon by Vespoid, but because they lost their food source!" Erik exclaimed excitedly. "I knew it! It might be barely plausible for Delex, but there's no way Vespoid could prey on Cephalos!"
Isis clenched her fist firmly. "So this means we can now confirm that the Vespoid nest is definitely in that waste disposal cavern, right?"
"Everything we've discussed so far can only be considered speculation."
"..."
Seeing Isis rendered speechless by his words, the Professor smiled and said, "But when it comes to investigations, it's all about bold speculation followed by careful verification. Now that we have the speculation, it's time for the verification step. Isis, Altaïr, you have a few hours to rest, recover your strength, and prepare for battle. I'll go explain the situation to the Elder. To safely enter that hidden waste disposal cavern, we'll probably need to make some arrangements. We'll depart around midnight to unveil the mystery of the Desert Queen."