"Huh, so this is it... Just like Rei said, there's a hole leading underground."
Marina murmured as she looked at the hole Grimm had opened.
Since Marina had agreed at the Fruit Pavilion to at least look into the Wisp for the time being, Rei—having finished his fruit water and bread—purchased a gold coin's worth of fruit water and stored it in his Misty Ring.
He would have liked to buy some bread as well, but unfortunately, the bread was baked to order as a finishing touch—a somewhat unusual production method—so purchasing any to go was out of the question.
After that, they stopped by the clinic so Marina could explain the situation. Despite being deeply reluctant to let her go, the staff eventually accepted it, and the two made their way to the Treant Forest.
Since Marina was with him, grabbing onto Set's legs and flying would have normally been fine, but she was wearing a white party dress.
Considering what that would look like from the ground, riding while clinging to Set's legs was simply not an option.
Changing into an outfit that wouldn't be a problem if seen from below was another possibility, but when she asked to ride on Set alongside Rei for once, he couldn't very well refuse her.
...The fact that Set also enthusiastically agreed—making it clear that was what he wanted—was a big factor.
Naturally, when they left Gilm, the people waiting in line to enter the city gathered plenty of stares at the beautiful Dark Elf in a party dress. But Rei and Marina, long accustomed to being the center of attention, didn't seem to mind in the least.
Thus, Rei, Set, and Marina—two people and one creature—made their way from Gilm to the Treant Forest. They naturally encountered woodcutters and adventurers along the way, but vaguely deflected their questions and arrived at the heart of the forest.
"Yeah. Shall we head inside for now? If Set keeps watch outside, there shouldn't be any problems."
"You're right. ...Alright then, Set. We're counting on you."
"Gruu!"
At Marina's words, Set purred as if to say, "Leave it to me!"
With Set present, most people wouldn't be able to get inside.
Reassured by that, Rei and Marina proceeded through the underground passage Grimm had made.
"It's fairly long, isn't it."
"The space where the Wisp was is quite spacious. Thinking about that, this much length is probably necessary."
As for lighting in the underground passage, Marina was handling it with her Spirit Magic.
(Hm? Maybe instead of trying to do something with my Terrain Manipulation, Marina could use her Spirit Magic to hide the entrance to this passage?)
As he walked through the passage, Rei belatedly realized this.
With his Terrain Manipulation, since he couldn't assign any special properties to the terrain he manipulated, he couldn't stop someone from directly digging in if the worst came to worst.
But with Marina's Spirit Magic, she might be able to set up some kind of countermeasure—triggering a defensive response if anyone other than authorized personnel tried to dig into the ground.
That was what he concluded.
Under normal circumstances, even Spirit Magic wouldn't be able to pull off something like that, but for someone like Marina—a first-rate... no, a superlative Spirit Mage—it wouldn't be surprising at all.
In fact, Marina's home in Gilm was equipped with extremely robust Spirit Magic security.
Of course, that wasn't something that could be done instantly just by deciding to do it; it required various preparations and a certain amount of time.
(For now, I'll ask Marina to handle it later—Lord Daskar can wait. ...Lord Daskar should have naturally thought of the option of relying on Marina, so... why didn't he mention it? Did he not want to rely on her? If that were the case, he wouldn't have wanted her help investigating the Wisp either, right?)
As he walked, Rei puzzled over why Daskar hadn't suggested relying on Marina, but ultimately, nothing came to mind.
His final conclusion was simply that Daskar had been so exhausted from work that he couldn't think that far ahead.
He didn't know whether that was the truth, but it was convincing enough for Rei, and he put the matter to rest.
"I can see it."
Right at that moment, Marina murmured.
Light was indeed visible ahead.
What was producing that light was something Rei, having ventured beyond this point last night, naturally already knew.
"I hope the Wisp's light hasn't grown any dimmer."
According to what Rei had heard from Grimm, the Wisp's mana should have been considerably depleted.
Given that it had teleported Lizardmen yesterday in that state, there was a real possibility it had teleported something—or someone—again while Rei was away from the Treant Forest.
Rei half-hoped against hope that it might open a path to Earth... specifically to Japan, so he honestly didn't want the Wisp weakened from overusing its mana in its current state.
(Ideally, I'd be able to communicate with it like I can with Set... but that's impossible.)
Since he could communicate with Set to a certain extent, they could generally understand what Rei wanted from Set and what Set wanted from Rei.
But that was only possible because Set was a being created through Rei's Beast Magic. Communicating with the Wisp in the underground space beneath the Treant Forest—a place connected to nowhere, one that would never have been found without Grimm—was simply impossible.
He did wonder whether there might be some other method. If the Wisp had been an ordinary monster, he might have been able to tame it to some degree. But the Wisp here was, in a sense, an existence specialized to function as a system.
How was one supposed to communicate with something that possessed no semblance of ego?
At the very least, Rei couldn't think of a way.
"This is... incredible. I never imagined there was a space like this beneath the Treant Forest."
Marina murmured earnestly as she gazed at the underground space.
Rei had felt the same way when he came here last night, so he understood her reaction perfectly.
"Looks like Grimm isn't here. ...I thought he might already be investigating the Wisp."
Since Grimm had mentioned last night connecting this underground space to one of his research labs, Rei figured he might have already linked them and begun examining the Wisp. But apparently, that prediction was wrong.
"Marina, it goes without saying, but..."
Saying that, Rei directed his gaze toward the light source of the underground space—the Wisp.
The Wisp, clearly different in size from an ordinary one, would be instantly recognizable to anyone as abnormal just by looking at it.
"Yes. That Wisp, huh. ...I've never seen one this large before either."
From her words, Marina must have encountered Wisps before.
But the Wisp currently at the center of Marina's gaze was clearly different from an ordinary one.
That was exactly why Marina voiced her surprise as she stared at it.
"Right? Well, anyone who sees that thing would know it's not ordinary. ...So, how does it look? Think you can research it? If possible, I'd like to be able to control it to some extent."
"That's... honestly, I'm not sure. Even if I try, there's no guarantee I can pull something like that off. But... I'll give it my best shot."
Marina was probably pleased to be relied on by Rei.
She knew she was working outside her area of expertise, but still, she approached the Wisp, wondering if there was anything she could do in the current situation.
She had hesitated over what to do first, but she likely wanted to examine the Wisp thoroughly with her own eyes before anything else.
Since Rei didn't have anything in particular to do while looking at the Wisp, he simply watched Marina in silence.
(Mana... mana, huh. If I could transfer my mana to that Wisp, it would probably resolve its mana shortage. But if that caused it to teleport something or someone from some weird place again, that would be a problem. So even if mana transfer is possible, it'd have to wait until I can control it properly.)
If he carelessly transferred mana alone, there was a possibility it could end up teleporting an enormous mountain this time.
For that matter, he didn't even know yet whether mana transfer was possible.
After all, this Wisp was the only being with the ability to teleport things from another world.
If they recklessly experimented with transferring mana to the Wisp and it ended up dying, there would be nothing they could do.
"Rei? What's wrong, staring at the Wisp like that?"
Perhaps curious about Rei staring intently at the Wisp, Marina asked with a puzzled expression.
"Grimm said this Wisp has consumed a massive amount of mana, right? So I was thinking about whether I could transfer my mana to it. Of course, I wouldn't try anything like that right away—not until I figure out how to make the Wisp act according to our will."
The amount of mana Rei possessed was immense.
So immense that without the Ring of the New Moon—a Magic Item that disguised his mana—anyone who detected his mana through some means would panic at the sheer volume.
"Ah... right. I see. I understand what you're getting at, Rei. But we haven't even started research yet, so even if something like that is possible, it's still a long way off. ...I just hope this Wisp stays alive until then."
Marina's words were cause for concern for Rei as well.
After all, no one knew how long this Wisp could survive.
Being a monster capable of teleporting beings from other worlds, it could reach the end of its lifespan at any time, or die from overusing its abilities.
He couldn't imagine there were other Wisps with such a convenient... yet dangerous ability.
(If it were a High-ranking Species rather than a Rare Species, ordinary Wisps would eventually evolve into the same form as this one... but the fact that Grimm didn't know about it probably means it's a Rare Species.)
Looking at the Wisp, which showed no movement whatsoever despite Rei and Marina being right there, he spoke.
"I'm praying the research results come as quickly as possible."
"You're right. But if we're going to do full-scale research, that should be done by professional researchers, not me. What I'm doing is really just mimicking their work."
"Even so, I think it's pretty amazing that you're willing to try."
"My, Rei, you do know how to say the right things. If you're relying on me, I suppose I'll have to try a little harder."
Whether spurred on by Rei's words, Marina approached the Wisp floating in the air—overwhelmingly larger than an ordinary one.
"Hmm, I thought this when I saw it earlier, but looking at it again up close, its presence is clearly different from an ordinary Wisp."
"I thought the same thing. For one thing, from what I've read in the Monster Encyclopedia, Wisps aren't supposed to be this large."
"The Wisps I've encountered before were all smaller than a human head, no matter how big they got. The smallest ones were about the size of a hand."
"Right. Hmm, but then... do you know what to investigate or how?"
"A professional researcher would know how to approach something like this... but this is a bit difficult for me."
After pondering Rei's words for a moment, Marina suddenly thought of something and murmured softly.
Then, a slight breeze blew through the space.
Through this space where there was nothing other than the underground passage Grimm had made.
Of course, since it was connected to the outside, it wasn't strange for wind to blow.
But for wind to blow at such perfect timing, there was definitely something unnatural about it.
"No good. I asked the spirits to check whether there was anything unusual about this Wisp from their perspective, but they found nothing. It seems to be an ordinary... well, I hesitate to use that expression, but all in all, it appears to be a perfectly normal monster."
"You asked the Wind Spirits? ...I didn't think of that approach. Ah, but in that case, what's next? Is there another way to confirm something?"
"Fire and water are out, but should I try asking the Earth Spirits? Though, since the Wind Spirits didn't find anything unusual either, it'll probably be the same result."
Thus, Rei and Marina continued investigating the Wisp before them, consulting each other as they went.