Returning to Childhood

The old man introduced himself as Setanta, the leader of the village.

After hearing the gist of what had happened-how Rem had pulled him out of an oil pool, and how everything around him seemed utterly unfamiliar to him, making him nothing like a local-the old man gave a slight nod, acknowledging the basic facts.

"Natsuki Subaru, was it? A strange name, strange clothes, and that hair color... How did you get here? And where are your parents?"

"...Mom and Dad are probably still at home waiting for me. But from the looks of things, I won't be able to get back for a while. I don't know how I got here, either. I just went out to buy a few things, and then, in the blink of an eye, I was in that forest. That's really what happened. I'm not lying."

The old man studied the faint confusion and unease on Subaru's face.

"You don't seem to be lying. Where is your home? If it's within Lugunica, getting you back should be a little easier."

"Lugu...nica? I've never heard of that country." Subaru gave a wry smile. "My home is in a small country in the east, I guess."

"The east?" Setanta frowned. "To the east of Lugunica lies the Great Waterfall. By your account, you came from the other side of it. Boy, are you making fun of me?"

"The Great Waterfall... Lugunica... Um, if it's not too much trouble, could you explain what those words mean first?"

Then he couldn't resist adding, "Also, why do you all keep treating me like a kid? It's been bothering me for a while now."

"Your appearance is certainly suspicious, but it would be too cruel for me to drive a ten-year-old child into the forest to fend for himself. If not for the taboo, I might even be able to make an exception and take you in."

"...I'm seventeen!"

"I see. Perhaps our countries calculate age differently." Setanta nodded without betraying any emotion. "Go outside for now. I need to think carefully about what to do with you."

"I feel like a mortal waiting to be judged." Subaru stood up with a miserable look. "Do you have to be so wary? People in this other world are pretty stingy with their compassion-"

Despite saying that, he was actually relieved. Talking face-to-face with an old man who was obviously so serious was exceptionally draining.

Subaru stood up, rolled his stiff shoulders, and headed for the door. Just then, he happened to glance at the window.

Glass.

It was smooth and transparent. Apparently, the craftsmanship of glass products in this other world was already quite advanced. But what stopped him in his tracks wasn't the craftsmanship of the window. It was the figure reflected in it.

"...Who's that?"

Subaru tilted his head, and the boy in the reflection tilted his head too. He raised a hand, and the reflection did the same.

"Wait, that's not right-?! Does getting transported to another world come with this kind of special reaction too?! How did I not notice at all before?!"

"Quiet down and get out. Still, a noisy child is easier to tolerate than a mean-spirited one."

"Old man! Do you have a mirror here?!"

"The toilet is over there. If you make a mess, clean it up before you leave. I won't go so far as to wipe a child's backside for him."

"Who can't wipe their own butt?! That's the kind of thing only a three-year-old can't do!"

Even as Subaru shouted back, he was already rushing into the little cubicle the old man had pointed out.

Then-at last, he got a completely clear look at himself.

In the mirror was a little shota.

He looked about ten years old. Subaru instinctively felt he should add a little to that estimate, because he still remembered the baby face he'd been born with.

But no matter how much he adjusted for that, there was no way a seventeen-year-old could look like this. His skin was fair and smooth, and the lines of his cheeks were several degrees softer than he remembered.

If there was one flaw, it was probably his eyes. They still retained some of their original sharpness, creating a curious contrast against his youthful face.

"Hmm... Aside from the eyes, I'm actually pretty cute. No wonder people always mistook me for a girl when I was little..."

Subaru touched his face in front of the mirror, then looked down at his clothes-his cheap tracksuit.

It fit his current body perfectly. No wonder he hadn't noticed all this time. Without a mirror, clothes that fit this well were the perfect disguise.

He stared at the little shota in the mirror, so familiar and yet so strange, and forced a smile to make the best of a bad situation.

"The goddess who sent me to another world was awfully considerate, even altering my clothes for me. But if she was going to be that considerate, why didn't she just show herself and say hello?"

"Please come with Rem. Rem will take you to your temporary lodgings. Also, please don't act too suspiciously, because Rem has been assigned to keep an eye on you."

"...I think I just heard something pretty serious. Watching me, I can totally understand. I'm an outsider of unknown origin, after all. But is it okay to just tell me that?"

After accepting the fact that he had turned into a child of around ten, Subaru had been allowed to stay in the village for the time being. Rather than being "allowed," though, it was more of an "observation period."

"It's fine. Humans are weak. They can't even do anything against weak mabeasts. Rem is the runt of the Oni, the weakest Oni. Although you have that irritating smell on you, even Rem doesn't think you're much of a threat."

"The weakest... If I ever saw a kid casually send a crocodile several meters long flying, I'd probably think a god had possessed them. Oh, speaking of mabeasts, there's something else I wanted to ask."

"What is it?"

"This village calls itself a secluded settlement, but it doesn't seem particularly opposed to outsiders. Didn't you say even merchants can come in and do business? That means you didn't move to a place like this to escape some disaster or hide from anything, right?"

"Of course not. Why would you think that?"

"If you weren't forced to hide here, why did you choose to settle somewhere crawling with mabeasts?!"

Subaru finally spilled the question he'd been holding in for so long. "The village is surrounded by those things! Isn't that way too dangerous?!"

"From a human's perspective, living here is indeed very dangerous. But for the Oni, this area is the best place to live and raise a family. The more mabeasts there are in a place, the denser the mana in the air."

"...Mana?"

Obvious exasperation appeared on Rem's face. She stared at Subaru for several seconds, trying to determine from his expression whether he was playing dumb on purpose.

"If Rem couldn't see your expression, Rem would really think you were making fun of her. Mana is the energy that exists in the air and in everyone's body, and is used to cast magic. Do you understand?"

Seeing that Subaru still looked completely lost, Rem sighed softly and explained it in detail.

Simply put, mana was magical energy. It was as classic a piece of other-world worldbuilding as there was, except it didn't just exist inside people's bodies; it also filled the air of this world.

The core of the Oni's fighting style was the horn on their heads. Its true function was to forcibly absorb mana from the surrounding air and convert it into their own power.

Ram had been able to tear more than a dozen mabeasts apart with that one attack because she had used her horn to absorb an enormous amount of atmospheric mana.

Mabeasts, meanwhile, loved environments rich in mana precisely because they fed on it too. The more densely populated an area was with mabeasts, the higher the concentration of mana in the air, and the higher the concentration of mana, the more mabeasts it attracted in turn.

In other words, this forest, where humans were in mortal danger at every moment, was a holy land perfectly suited to the Oni for fighting and training.

"...So that's how it works. Doesn't that mean a helpless human like me living here is like a rabbit moving into the middle of a wolf's den?"

"Don't worry. There's a barrier around the village, so mabeasts can't get in. Just don't go outside the barrier on your own. Though even if you wanted to run off, Rem would be keeping an eye on you."