"In that case it would be unwise to try saving them. ...is there a way you can check if we've got a Limbo -"

"If conjuration therefrom works normally, but it is notable that people trying to conjure the complete works of Limbo and specifying no further than that have only ever got our Limbo..."

"Which only has people from your world, I assume they've checked that -"

"Oh yeah it would've been noticed if there were extras."

"Conjuration works fine from our world, and the one you fought the war in?"

"Name something which is definitely not magic which probably exists only in your world and not mine. But yeah, works in Arda all right."

"Transfiguration essay next to my bed?"

...essay? Essay.

"So odds are we don't have a Limbo or anything akin to it."

"Could just not be called that and we could've missed it."

"- but then you could get posthumous works, right -"

"Name somebody dead who'd definitely write were it at all possible."

"Our grandmother - on my father's side -"

Posthumous works thereof -? "Nothing. Which means only that you don't have an afterlife where people can produce nonmagical writing to which your grandmother went, not anything stronger than that, but it's suggestive."

Nod. "Okay. We should draw up a list of experiments - of which the most urgent are whether our magic can harm you, since if it can't we have a lot more freedom to do everything else -"

"Except for the part where some of it's intractable to actually test."

"It's mostly not intractable so much as 'debatably a good idea'."

"You were guessing fifty-fifty on one of those curses that can't be cast without malicious intent."

"Yeah, I can think of ways to check that but they are all very debatably a good idea."

"Do any of them not involve finding someone with malicious intent and inviting them to mind-control me."

"Yes, some of them involve altering my beliefs temporarily. Or same with a daeva who would be less bothered by it and less difficult to contain if it worked."

"I'm not actually sure how I'd bet on bindings versus mind control curse."

"And Limboites have the invulnerability without powers but we have no way to go and chat with them." 

"I can send them letters but not a wizard."

"There might not be a safe way to check it. Which - is a problem, because it would not surprise me at all if it were attempted."