"What's the point of having somebody wield you when you can run around like this and do all the things you can do?"

"From their perspective? Having a Device makes a lot of spells way, way cheaper, and lets them cast from the Device's power instead of their own, and it's just generally way more convenient, and also they have more control over exactly what things I'm running around doing. From mine? Who the fuck knows."

"Huh. Sounds like a good deal you wound up here."

"Yeah."

"You didn't have one of those wielders? More than one? Is it a one-to-one-thing?"

"It's a one-to-one thing for me, definitely. There might be some mages out there who use more than one Device, there might even be Devices out there who can have more than one wielder somehow, but I haven't seen any."

"I'm asking whether you had one because I'm curious if there's a magical connection that might persist across worlds, not because I felt like intruding on your personal life."

"I didn't have one when I got summoned, no. But it's definitely the kind of connection that would persist across worlds, at least in the group of them I'm used to."

"I'm curious about that grouping, too, how does that work?"

"Search me. Before I came here, I knew what a world was, and I could get to any of them I knew about with magic, or use a random transport spell to find a new one, and they all had the same kind of magic and worked the same way. Now I'm here and the dimensional coordinates are hell and gone from anywhere I've ever been and there's no magic I'm used to and a bunch of kinds I've never heard of and all the space between your planets is full of air."

"...What else would it be full of, cats?"

"In every other world I've been to, except for dimensional pockets where the rules are different, planets are wrapped in air and the space in between is just empty. Vacuum. Interdimensional space has little pockets of matter in between all the... interdimensional space, and those are mostly full of air wherever there isn't anything else, but they're also not usually very big."

"What is a dimensional pocket, and what's interdimensional space?"

"Interdimensional space is... between worlds? Or everywhere that's not a world? I don't know the theory at all, I've just been in and out of it some, enough to get a sense of how the coordinates work. Dimensional pockets are stable pockets of matter in interdimensional space. It's sort of all one thing but it's also sort of not all one thing at all."

"Huh. And how do the coordinates work, then?"

"Differently than coordinates for places inside worlds. Inside a world, you have the dimensional coordinates of the world and then the physical coordinates of your location in the world. In interdimensional space, it's - measured almost a completely different way; physical location coordinates only apply inside dimensional pockets, and the locations of dimensional pockets in interdimensional space don't work the same way as the locations of worlds, and in different parts of interdimensional space, coordinates for dimensional pockets work a different way than other parts."

"That sounds complicated. Any established way to map it?"

"Probably lots, but I never learned any. I have a built-in coordinate sense. I don't do it by numbers, I do it by feel."

"Fair enough. That a Device thing or a you thing?"

"A me thing, I guess. It's not a Device fundamental - it's built in, but it could've not been built in. So probably there's other Devices who don't have it."

"...Hi?" says Brilliance, uncertainly. That is a weird look she is giving him. He is confused and mildly alarmed.

"Huh?"