"...It certainly feels like we're back."
Those were the first words to leave Anastasia's mouth upon returning to Elgin through the passage Grimm had prepared.
This space beneath the Treant Forest where the Wisp dwelled was undeniably a place Anastasia had grown somewhat accustomed to.
Having returned, she approached the Wisp as if she had forgotten all about the other world.
Watching her, Rei moved away from the others and toward the wall before murmuring quietly.
"Grimm, are you here?"
'I am here. It seems you've returned safely—which is most welcome. It appears you've accomplished your purpose as well.'
The voice reached Rei's ears, but no one else seemed able to hear it. That something like this was possible was precisely because it was Grimm. Not showing himself directly was likely his way of being considerate toward Anastasia and the others.
For Grimm, Anastasia and Fana were people he had known for some time. He'd been sufficiently interested in the Wisp to investigate it himself when Anastasia and the others had left this underground space at night, so it was only natural he already knew about them.
And yet, he had kept his existence completely hidden from Anastasia. The sheer magnitude of that ability was something even Rei could appreciate.
'I am glad you returned safely.'
Grimm's words were far from what an Undead would say to a living person. If anything, it sounded more like a grandfather calling out to his grandchild.
For Grimm, Rei's existence was special in many ways. That said, if Grimm had been an ordinary Undead, he never would have been this friendly toward a living person. It was precisely because he was a special kind of Undead that he could do such a thing.
"Yeah, I somehow managed to settle things with Anastasia and the others. So, I have something I'd like to ask. Right now, the connection between this world and the other one is being maintained by your power, right?"
'Umu.'
Grimm replied, and the somewhat proud tone in his voice was surely not Rei's imagination.
"In that case, does that mean without you, the connection between these worlds can't be maintained?"
'That would be so.'
"...And what do you plan to do about the other world? Actually, I'd like to go back and explore it more."
'Hmm. It can be done if I try, but it is not a particularly welcome development for me.'
"Really? Don't you have an interest in the other world yourself?"
When Rei asked this, Grimm responded with silence.
In truth, just as Rei had said, Grimm likely was interested in the other world. The existence of Centaurs and Dragonias. And above all, Rei's activities in that other world had been confined solely to the plains.
According to what the Centaurs had told him, there were other beings beyond the plains—entities that had built a corresponding civilization and formed nations. Rei wanted to visit those places if possible.
Since it was another world, there was a possibility of unknown Magic Items even for Rei. And more than anything, he had come to know of the Dragonias Queen's existence.
Of course, even from Rei's perspective, the Queen was clearly abnormal—an entity that seemed to have come from another world just as his own group had. But the fact that she had appeared in that world meant there was no guarantee others of her kind didn't exist as well. And if there was another being that had come from somewhere else, defeating it might raise his Terrain Manipulation level again.
Considering the possibility of other unknown technologies, it would be impossible not to be curious about the world where the Centaurs lived.
'Hmm, that is to say... you want me to maintain this connection as it is?'
"Yeah. If you have an interest in the other world, it's not a bad deal for you either, right? Besides... I'm not telling you to maintain this connection yourself. With your abilities, couldn't you create a Magic Item that keeps this world and the other one connected?"
'...I see. A Magic Item that fixes the connection between worlds. Actually, I had considered that myself.'
Just as expected.
For someone as capable as Grimm, it wouldn't be strange for him to think of an alternative method rather than maintaining the inter-world connection himself—and the first thing that would come to mind would naturally be a Magic Item.
"And? Were you able to make one?"
'That is a difficult question. I did manage to make one, but its effect is highly unstable. Depending on circumstances, it would not be surprising for the connection to sever at any time, and once severed, reconnecting to the other world would be nearly impossible.'
"That's... quite troublesome."
Not knowing when it might become unstable, and if it did, Grimm would need to take measures immediately. Moreover, if the connection were severed, this world and the other could never be linked again. Rather than relying on such an unstable Magic Item, it would be far more reassuring for Grimm himself to maintain the connection.
"Can't you do something about that instability?"
'Let me see. There are various difficult theories involved, but to put it in terms easier for you to understand: to anchor this world and the other world together, something with a mutual relationship is needed. As for items from this world, the Magic Item I prepared is sufficient, but materials from the other world are lacking.'
"Materials from the other world? Would any kind work?"
'Of course, not just anything will do. It requires materials with an appropriate... let us call it an "existence rank."'
Materials.
Hearing that, Rei thought about what was stored inside his Misty Ring. A wide variety of Dragonias corpses. The overwhelmingly abundant ones were the red-scaled Dragonias that even Rei's Flame Magic couldn't kill, but Dragonias with other colored scales were also stored in respectable numbers.
(No, wait... don't Dragonias corpses become unusable by the next day?)
That was likely the greatest obstacle.
Additionally, Rei suspected that the Dragonias had come from yet another world entirely different from their own, so whether a Magic Item fixing the inter-world connection could be crafted from materials stripped from their corpses was questionable at best. Nevertheless, as long as the possibility existed, there was no harm in asking.
Making that judgment, Rei spoke toward Grimm—though regrettably, he couldn't see him.
"What if I had Dragonias corpses?"
'Those... would be unusable, would they not?'
"Of course, under normal circumstances, it's true they'd be useless. After all, they become unusable by the next day. But that's only if we're talking about an ordinary Alchemist. With your abilities, Grimm, if I gave you the corpses, couldn't you use them as materials right away?"
'How naive. They might be usable as materials at that point in time, but if the Dragonias materials became unusable after being incorporated into a Magic Item, what do you think would happen? That would be far more dangerous than simply using a normal Magic Item.'
What Rei was thinking, Grimm had naturally already considered. However, because Grimm knew the characteristics of Dragonias corpses, he had no intention of carrying out what Rei suggested.
But Rei directed his gaze toward the hole connecting to the other world.
"That's true. In this world, Dragonias corpses become unusable by the next day. But what about in the other world? There, wouldn't they be perfectly usable?"
At the very least, Rei hadn't heard from the Centaurs in the other world that Dragonias corpses became unusable by the next day.
(The grove near the settlement where the Spirit Egg was buried... well, that was special in many ways.)
The Dragonias killed in that grove had vanished by the following day. Considering that, it wasn't something inherent to the Dragonias themselves, but rather the fact that the Spirit Egg had been buried there.
'In the other world, you say... I see. Since I am maintaining the world's connection, I cannot move too far away. But conversely, that means I can move away to some extent. How fascinating.'
Grimm seemed to find Rei's words unexpected. Of course, it wasn't an outlandish suggestion—it was the kind of surprise that came from an egg of Columbus, a shift in perspective that seemed obvious in hindsight.
"Does it seem feasible?"
'Hmm, let me try. Regarding Dragonias corpses, how many do you have to spare?'
If the number was small, he would need to proceed carefully in order to conduct various experiments. Proceeding carefully naturally meant slower progress, which was not desirable for Rei.
Judging that there was no problem, Rei nodded.
"Just corpses? I have quite a lot. And not just ordinary Dragonias, but intelligent ones—what would be called High-ranking Species in this world."
'Oh.'
At the words "High-ranking Species," Grimm's voice carried genuine interest. Indeed, if they were creating a Magic Item to connect two worlds, one using High-ranking Species materials—which would yield higher performance—would unquestionably be better.
"That said, naturally, I don't have that many High-ranking Species corpses."
The way Rei said this carried a hint of guilt. Naturally so. Among the Dragonias High-ranking Species, he had obtained a fair number of corpses of the seven-colored Dragonias—the supreme existence at the very apex—but when it came to others, they were quite few for various reasons.
That was why he felt guilty about not being able to provide Grimm with a large number of High-ranking Species corpses for this matter.
On top of that, the Dragonias Queen's corpse had been burned to ash, leaving truly nothing behind. Strictly speaking, only the Core that had raised his Terrain Manipulation level remained, but even that was already gone.
If they were creating a Magic Item to connect the other world to this one, the Queen's materials would have produced the best result. But no such thing existed inside Rei's Misty Ring.
"If things were ideal, it would have been best to have the Queen's corpse—the Highest-ranking Species among the Dragonias—but I'm sorry."
'It is of no concern. I do not believe you would so easily overlook a being that could serve as Magic Item material. That means there was no choice but to do what you did, correct?'
"Yeah. She had powerful Regeneration Ability. No matter how much I attacked her normally, it was meaningless, so in the end, I needed to burn her thoroughly until she could no longer regenerate."
Using the Flame Emperor's Crimson Armor, Rei had exhausted his vast magical power to the point of depletion. No—magical power alone hadn't been enough. He had even used his life force to finally defeat her.
She wasn't particularly strong, but she was tenacious. For Rei, the Dragonias Queen had been a truly troublesome opponent.
'I see. In any case, I understand the situation. I will think about the Magic Item matter for now, so leave one Dragonias corpse here. Ah, a normal Dragonias will do, not a High-ranking Species. I need to leave the corpse in the other world and confirm whether it can truly be used as material.'
Rei nodded at Grimm's words. Then, unseen by the others, he retrieved a single red-scaled Dragonias corpse from his Misty Ring.
Immediately after, the corpse vanished to somewhere Rei couldn't see.
He had no idea what had happened, but it was easy to imagine that Grimm had done something.
"Then we'll be heading out soon."
'Umu. I shall do my best to create a Magic Item using the Dragonias corpse as well.'
Nodding at Grimm's words, Rei called out to Anastasia, who was still observing the Wisp, and the others before leaving the Underground Space.
Fana had been concerned about what they would do about Set, but for the moment, Rei managed to brush it off with a somewhat forced explanation about his master taking care of things. And when they emerged to the surface—
"Huh?"
The moment they reached the ground, a human-shaped creature about the size of a palm, with wings growing from its back—a Fairy—flew right past Rei's eyes, and the word slipped from his mouth before he could stop it.