Pop up through the portal.

The sudden shift in gravity causes you to feel nauseous and dizzy for a moment. In an instant, you were falling down, and then jumping up. Thankfully, the old man helps you stay balanced as you find your footing adjacent to a portal of his own. This one has been drawn onto stone in a room covered in shelves which hold various bottles and books, but it's otherwise a rather small room. You look down to see your friends, but a moment later, it shifts back into blackness.

"Welcome to my house, Kyle," he says. "Make yourself at home."

"What did you want to talk to me about?" you ask.

"I understand that many terrible things have likely happened to you here in Absoterra, but I assure you that I'm not one of them. Relax and follow me," he says before strolling back towards the door, using his quarterstaff to aid him.

You follow him through into another room, and this one is much larger. The walls are wood, and the floor is as well, though there are numerous glass cases and other displays all over an expansive museum of wonders. Rather, they would be wonders to anyone else, but to you, these are all too familiar. In their normalcy, ironically enough, they are truly wondrous. These are not items of this world.

With Ealdorman as your tour guide, you're brought through to each display, which he proudly showcases. The first is a weathered Super Nintendo. Next is a shopping cart from Safeway. He shows you a revolver, as well as a switchblade knife. On top that, there are items that appear more fitting for the setting, as they are objects from ancient times, such as a helmet from somewhere in the middle ages, or a vase that looks far older. There are a bunch of books as well, from The Hobbit to all sorts of manga, such as a few volumes of Dragon Ball Z and Monster Musume. It's overwhelming. There are dozens of items here, and they're all unmistakably from Earth, and all from different periods of time. Most are scratched, worn, or nearly destroyed, but it causes your heart to race. It's surreal to see all this, and so suddenly. Your mind races with questions, so much so that you don't know where to start.

"How--" is all you mutter out as you look around in awe.

"I'm a collector," he says. "These various treasures I've either found, bought, or was given, over many years. It hasn't been easy, nor has it been cheap, but I'm the proud owner of the most grand collection of goods originally from Earth. Everything in this room is the most definitive proof of Isekai Theory so much so that I'd rather not call it a theory at all. And I mean everything."

"Are they that common?" you ask.

"I wouldn't say that. But over the ages, things and people have come through, either by the will of somebody on this side, or purely by random. I'd guess it's mostly the latter. I'm sure there are many nobles out there who treasure these items as well, so it's been hard to get this many, let me tell you."

"So you know. About me."

"You did admit it at the meeting, which I did overhear before entering. But I had my suspicions before that." From a nearby shelf, he pulls down a book. It's the English translation of the first volume of the Konosuba light novel. "A man, transported to another world. A truly amazing idea, isn't it?"

"A little overdone, but yeah."

He chuckles.

"Can you actually read these things?" you ask. "It can't be easy to translate. I've actually met someone else who had been trying."

After stowing the book away again, he continues to walk around the room with you. "Perhaps."

"You know, if you want me to trust you, it's not helpful to answer like that."

"You're not wrong! Then hold on. Follow me, to one more place. Then we can speak more."