"Any spell is intellectually interesting so intellectual interest doesn't count. It's admittedly pretty subjective but if you come of age a Legilimens and knowing the Unforgivables and I'm presuming here there are also things he hasn't admitted to in two hours of casual conversation - that meets common usage - uh ,and world conquest is considered a sort of Dark ambition though that's mostly just because the people who try it keep being evil -"

"The world is really badly run. If it were nicer I bet I'd only be a tiny bit tempted to rule it."

"How much nicer?"

"...really, really nice, admittedly."

Snort. "I'm not sure why world conquest is so popular among the evil."

"With wizards I think part of the problem is that if you're insufficiently paranoid you never get anywhere and if you're sufficiently paranoid you know lots and lots of really evil magic and might be tempted to make exceptions on the not using it."

"That'd be a fairly satisfying explanation if it were only wizards we were explaining."

"I haven't actually paid much attention to Muggle would-be rulers of the world, do they actually suck more than, like, the typical person?"

"Possibly only insofar as they acquire opportunity, I suppose."

"Most people are kind of terrible. - oh, your demon acquaintance laughed at me for suggesting a model size in cubits, the world I take it having picked different units of measure, and I didn't actually look whether it was our or Revelation's -"

"She was expecting meters - I would've warned you to go metric if you were American but I confess cubits did not occur to me, they are sufficiently obscure to qualify as a Bible reference even without further clues because one only hears about them for Ark reasons."

"I have never heard of a meter."

"One ten-millionth the distance between the equator and the North Pole. The French came up with it. We use that?"

"I still have no idea how far that is."

He makes an effort to gesture at approximately the right length without letting go of his book. "They came up with it a couple years ago, I remember reading something about it."

"Everybody uses that, the United States held out with feet and miles and whatnot till well after my death but eventually standardized, you guys switched earlier than that."

"Well. Timothy's going to take over the world so he can pick the units and he doesn't have to pick French ones."

"It'd be convenient to be able to trade with Revelation, though. And copy their stuff without converting units."

"The argument for metric is everything is powers of ten and there are convenient equivalencies like a cubic centimeter being a milliliter. The argument for Imperial - though it did not in my lifetime include cubits - is that it's better for measurements of human-scale things like the weather in places people live or human heights."

"You can pick, kiddo."

"That's no fair, if it actually matters I can't just be prejudiced."

"Yeah, exactly."

"Something wrong with France?"

"Well, it's kind of in the middle of a horribly bloody civil war, there's that. And also my grandfather's second wife is from there but it is unfair to blame the country for her, if you think about it they really got rid of her as fast as they could."

"So that matches, does it."

"The Elves have - I thought Elves don't die."

"Oh, let's see, do I have notes on the -" Rummage rummage. "They do if they keep yelling at the god of the dead for reembodying them."

"Ah."

"My mother didn't want to die."

"No one's saying she did, the Elf versions are obviously a lot of kinds of different -"

Look how unopinionated this demon is.

He goes back to his book.

"...the Elf version of Minor does outgrow the grudge, I hope?"

"Never actually discussed it with him, somehow."

"Right, I suppose you were all busy with far more important stuff."

"I had some downtime, mostly while flying to and fro, but Curufinwë was generally working on technical problems in a stationary sort of way."

"I really wanna meet him."

"Unfortunately even if I open the door for you traveling by lightleaper takes five days to get where he is."

"That's not that long. And I bet he could help us figure out the modernization stuff so we can get the Philosopher's Stone faster."

"Someone'd have to be holding the door, though."

"I'm sure at some point it'll be worth coming up with a rotation of door-holders and making the trip but when we have a more complete proposal in mind and know who to steal away, I think."

"I guess I don't wanna meet him while I still don't know anything and he'll think I'm stupid."

"We might end up wanting to kind of steal a bunch of people. Definitely worth waiting."

"...Do avoid mentioning to other demons that Quendi can be resurrected, it'd be a mess. But the same way that's doable, they could also be duplicated if they so desired."

"Be a - ohhhhhh. Yeah, noted, though at some point it'll be obvious there're two Earths. - I am not at all sure I was convincingly from 2179 -" and he recounts the conversation -

"...she will think you are weird and if she notices I wrote the song she may ask me about you but I don't expect her to be lastingly curious, let alone suspicious. Also I did not expect her to hit on you but I'm not sure a summoner's ever let her talk before so I didn't have great data on that."

"That is what she was doing? I was not sure if I was missing something important about pants - pants are confusing -"

"Nah that was pretty unambiguous. Not seriously, she would have been surprised if you'd run with it, but that is the structure of the thing she was doing."

"...okay."

"He's hopeless with girls."

"No one can have everything."

Oh look how few opinions Cam has.

And whose throne room is in the model? 

Revelation's, but that could be because of where she thought she was.

"Yeah - can you get ours if you're going for it?"

Cam makes an attempt - "This it?" It is.

"So that'd explain previous conjuring only pulling from the home dimension."

Nod.

"If there're really untold numbers of universes, and the magic's somehow contagious...we're not going to have enough demons."

"If dead summoners become daeva anywhere we might be fine."

"That's the next thing to check, I guess, go to London and find some dying people..."

"Discreet ones, unless we want all Hell knowing as soon as one dies all about the other Earth."

"That might be a little challenging, I have no idea how to assess the discretion of someone on their deathbed and no one I know is currently dying."

"We could try finding people who seem likely to be angels or fairies instead but I'm not confident in my guess of how that happens and it'd only slow it down anyway."

"If we've got a solution to death I'm not okay with keeping it secret anyway, so if the first one worked there'd be a thousand more the next day. Might have to abandon discretion."

"This also means there will be daeva on the same planet as wizards, even if it's somehow only for immortality and nobody uses them for anything else."

"Yeah, I realize. And you can't even roll it out just among Muggles because every wizarding government will investigate something that looks a lot like teaching Muggles magic."

"So the 'separate planets' security measure is a no, I suppose, which makes it a bit more urgent to test resistance to mind control or at least how it interacts with bindings."

"Yeah. Do you have a friend who'd be willing to be a test subject there?"

"Doesn't come up as a topic of conversation very often. I have guesses but only that."

"Why don't I check on humans whether I can test the Imperius under conditions that are not utterly horrible, and then we can ask for interested daeva test subjects."

"Okay."

He races through the hallways. People are dying, and now it's potentially within his control and so very very distracting. She'll probably be in the library -

"Miranda?"

There she is. "Hi!"

Every silencing spell he knows and he switches to Igbo. "I have just stumbled on an opportunity that is really important - might, among other things, end death - but we need a fair bit of information about the interaction of two different magic systems to be sure it's safe. Luckily the opportunity also involves the ability to travel outside the jurisdiction of the Ministry.

The opportunity doesn't at all depend on your answer to this, and I'll find things for you to do either way, but - do you want to learn how to throw off the Imperius and are you willing to participate in experiments into how much senblance of consent is compatible with casting it."

"- you don't think my being an Occlumens will throw off the results -?"

"I am optimistic it will make you unusually good at it and therefore the experiments unusually not horrible, I'm guessing I could tell the difference between 'cast it and you brushed me off' from 'that isn't evil enough intent to cast it in the first place'."

"I'll try it at least once."

Nod. "Come with me - you won't be gone long, we can stop time once we're there."

"Okay." She follows him as briskly as she is able, scribbling a note as she goes. It paper-airplanes away.

Then they will reach Minor sitting at the door of Milliways. 

"I said you should pick someone else."

"Yeah, but you had bad reasons. Close the door -"

It closes. 

"Okay. Sorry for the urgency. Now that death might be fixable I find the fact I'm not going around to get literally everyone who's dying - stressful. You can have as long as you want now."

"Why did you want him to pick someone else?" Miranda asks Minor. "Are there other Occlumenses who can throw off Veritaserum around?"

"It's the Imperius, throwing off Veritaserum's not anywhere near enough - did you know he even knew it -"

"No but I'm glad he told me he did instead of not that if he was going to know it anyway!"

He sits down. "This is Milliways. It is an interdimensional bar; the door connects up to different worlds, sometimes. Some of those worlds are ahead of us in history and technology. You can buy books from the year 2000 and the year 2150 and so on from the bar; she can also introduce herself. Like I said, you can take as long as you want to think about it now the door's closed. Or ask questions or whatever -"

"What does the Imperius Curse have to do with ending death?"

"I learned about a new form of magic, while I was here. It's called summoning; we should change the name of the Summoning Charm to minimize ambiguity. But anyway. There are three realms called daeva realms; they're known as Heaven, Hell, and Fairyland, though I'm going to fight really hard to get them known as something else in our world. Hell is populated by demons who also need a name change for Muggle relations reasons. They're people, indestructible, who can make arbitrary material objects. 

- by 2100 lots of very scary stuff has been invented or discovered, and the ability to make arbitrary material objects fairly trivially permits you to destroy the world.

Heaven is populated by angels, who can change any thing into any other thing, and Fairyland of course by fairies, who can move themselves or other things with a lot of speed and precision. None of these have any stamina limits or usage limits.

Daeva can be summoned; people on worlds that have discovered this summon them under strict constraints to trade them favors. And anyone who has summoned a daeva becomes one if they die."

"You could call me an 'apsel' if you don't like 'demon'," Cam says.

"...and you need to test the Imperius but not actually on a daeva..."

"Might be that I can't cast it for research purposes at all; conventional wisdom is that one can't. Might be that I can, if I am in fact intending to be some level of awful. - I'm pretty sure you can stop me, it took me an hour and a half the first time but you picked up Occlumency faster than I did.

Might be that the requisite sort of intent is bad enough I am not willing to try it on someone who I don't expect will be able to throw it off."

"Okay. If you can't cast it for research purposes what's the plan?"

"Uh, candidate plans include 'involve someone who is misinformed in a direction that'd enable them to do it', 'involve someone better at it than I am', and 'cast it on people without consent -' the threshold's a lot lower there, and I know one or two people who would agree afterwards it'd been the right thing to do and also still feel safe around me..."

"What's it like?"

"Pleasant. Vaguely dissociative."

"It'd probably make it a worse test if you outline what'll happen if I don't throw you off?"

"I'm going to start by trying while intending not to do much of anything, but I don't expect that to go through, and it's very possible it'll go through only at intent to do something you would not be okay with. You can place as many constraints as you'd like on what can happen but that makes it likelier it just doesn't go through."

"How about you can do whatever as long as you do it in front of Minor."

"We can try that."