"Do you find it objectionable or just silly like the owls?"

"Silly but in a more juvenile way."

"I have no idea why it's called that beyond 'the founders named it'."

"They had weird taste in names, then."

"It was around a thousand years ago, maybe tastes in names changed between then and now like between now and 2179."

"Hog. Warts."

"You call yourself a demon and the place you're from Hell!"

"It's called that in English because of some mythological overlap! In demon languages it's called other stuff better translated as 'maker' and 'emptiness'!"

"Well, Hogwarts is Hogwarts and no one has time travel good enough to go ask the founders why."

"Yeah, I noticed the limited state of the art on time travel."

"Promising as a field of research but - probably never going to be able to reach back years, not without significant risk of disaster."

"Disaster, oh no." Sigh.

"...do you have preferences about what I tell people who I have running errands -"

"I would consider it unreasonable to ask anyone to keep the obvious thing secret."

"If I need to get permission from the board of governors to allocate this wing of Hogwarts to time travel magic and so on, and I probably do, some people will be impressed with you."

"...the upshot being?"

"Even if you'd consider it inappropriate to have preferences about what people know, you might still consider yourself entitled to have preferences about whether people come try coaxing you into killing their enemies for them or just striking up enough acquaintance that the threat is implicitly present."

"I would not like to be coaxed into killing people, I find I have no taste for it at all."

"I noticed. So I might neglect to mention things to people who are likely to be stupid, if that's all right."

"Thanks."

"And until we know whether mind-controlling magic works on you."

"Yeah. What's the safe testing-it-out range of spells look like?"

"Cheering charm? Though part of the problem here is that even if you're immune to most things, the scariest stuff is also the stuff it's rarest to be able to counter - even if you shrug off everything we try I wouldn't give it better than 50-50 that the Imperius doesn't affect you - was that in the notes -"

"I mean, if it's an extension of my indestructibility it might work the other way around, I am just as vulnerable to a pinprick as you are but I just stay only yea vulnerable even if the pin is applied with more force, but point taken - if it was in what I got I haven't found it yet."

"There're three spells called the Unforgivables, because attempted use against a human or the other species we are lately acknowledging as people is an automatic life sentence in Azkaban. One does mind control, one does torture, one is instantly lethal. Why they're a bigger deal, by law, than other ways of achieving the same effect - love potions aren't even illegal - is mostly historical reasons, but it's also claimed they're impossible to cast without malicious intent - you couldn't use the Killing Curse to help someone in pain pass quickly - 

- it is not an area with any published research, so I am not especially equipped to guess if that's right."

"Is your wand inherently magical?" Cam wonders.

"Probably, why -"

"Demon powers are useful for finding things out, I can conjure by things like time and location to a certain extent without knowing what I expect to get, it might let me see somebody unexpected with a wand on them coming if I could make them, but if I can't it won't work."

"You're welcome to try - also, if you can make them then no one'd mind too much if you broke them in a fit of paranoia, while if you can't then that'll be very unpopular, warranted as paranoia probably is."

Cam is now holding what looks like a duplicate of Timothy's wand. "It is still possible it won't work, like this, depending on the way in which magic wands are that."

"But you can use it for checking, that's good. I can check if it works -" he extends a hand for it -

Cam hands it over.

He makes a sharp precise gesture, then a different one - "Nope. Looks like you can make inert wands."

"Well, still works forensically and won't upset whoever sells them."

"Yeah. ...this also probably isn't in the books I recommended you, but wizards can do some stuff wandless, not spells but you wouldn't want to assume a wizard without a wand is effectively a Muggle."

"What kinda stuff?"

"Some people are Animagi - can turn into animals - very skilled people can still Apparate - there're cultures that don't use wands and do it all by gesture or with some other focus but that's near-impossible to pick up if you don't start with it -"

"Noted."

"We can take as long as we want, subjectively, to bring any of this to the attention of any people I don't trust completely."

And someone comes racing around the corner, raises an eye at the door, and then raises an eye at his brother. 

"Hey! Minor, this is Cam; Cam, this is one of my little brothers."

"We're in the same Arithmancy class," he says, squinting at the bar again, "so not that little."

Timothy lets the door close. 

"Hi," says Cam.

"Hi - can you actually fly with those, I thought humans didn't have the right skeletal structure for that - oooh -" and he races over to peer at the window - 

"...Yes, I can fly with these."

"How do you do it? Where is this place?"

"I flap. It is called Milliways."

"I mean how do you do the spell for the wings, not how do you fly once you've got them. What're the stars - is there a vantage point where I'd get this view - why are so many of them exploding, stars explode but in any given night sky there really shouldn't be several of them doing it -"

"Didn't use a spell. I have no explanation for the stars."

"...okay, potion, whatever, if it's proprietary I'll pay you, or Timothy can give you a continent -"

"I don't have many of those left to give out."

"I'm not in the market for a continent. If you want wings you need to be done growing and certain you care to keep them first."

"Okay - Timothy, what -"

"Cam is from the year 2179."

"That's the most important thing that has ever happened."

"I think you could make a case for the discovery of fire."

"Not if you guys were remotely efficient - what can you do, what do I need to learn -"

"There's a confounding factor here where my world also has a different magic system."

"Huh. How? Is your magic system the one that does time travel -"

"No, this location is a separate thing."

" - okay -"

"I wrote Father. Things get significantly nicer for Muggles in the future, we want to roll things out as quickly as possible without enabling certain institutions which are supposed to die very shortly. Did you have hypotheses on why electric devices don't work at Hogwarts, it turns out to be important -"

"Told you so. Likeliest explanation is that the lightning ward dissipates inorganic concentrations of electric charge, we can lobby to have it fixed if you stop hoarding your political capital -"

"There are no resources I am holding back from this, promise."

He bounces into his brother's arms. "Whatdoyoudo with electricity - is there something I should read -"

"There is nothing entitled A Wizard From 1802's Guide To Electricity but I gave your brother some books, you can have copies too if you like." Books.

"You can conjure books? Do they not have copyright charms -" he snatches them -

"Different magic system. No such thing as copyright charms," says Cam. "I don't actually know if a copyright charm is the right kind of thing to obstruct me."

He flops down and starts reading. 

"...anyway. I can write a petition to get electricity working in Hogwarts but that's probably not the first thing we should be doing."

"Are you imagining getting started with or without me on hand, different implications there."

"What are you comfortable with?"

"I mean, it's much faster to do most things with a demon around, I'm just contemplating logistics, don't know how long you want to wait."

"Conveniently if I keep the door closed there aren't even people dying while we make up our minds. We might as well test whatever's useful first, possibly with the exception of keeping the door open long enough to fetch my father because he'll think of things I won't."

"Yeah, that seems worth it."

"Minor, can you go get an owl -"

"You go get an owl."

He makes another paper airplane instead, stands and holds the door and watches it fly off.

"Owls," mutters Cam.

"If you've got a fancy futuristic way of reaching my father I am sure he'd be delighted to receive a message from that instead."

"If you happen to know exactly how far away he or a place he'll look are, I can drop something there, but there would need to already be a thing. Can't pilot a drone if electricity doesn't work."

"I know where the house is, but probably not exactly enough - if you could make, like, a really good map -"

"The map would have to have already been mapped; can you name one of sufficient quality?"

"You can't do just a small version of the whole island - anyway, no, I don't know a sufficiently good map for that -"

"I can, but less magic parts. And we don't have room for one big enough to see a house."

"Owls it is, then."

Snort.

"What are you writing him do you even know all the things he'll need to know -"

"I'm sure I don't. I was planning to just tell him to come here."

"Could attach some doodad, if going through Hogwarts won't permanently break it, I don't know how plausible you can make the urgency."

"If we tell Dad come here right away he'll Apparate to the gates and then fly from there, that's not the problem - Timothy you could try to talk an Elf into taking a message -"

" -oooh, that's worth a shot -"

"These are the magical slaves?"

"Yes. - if you object we don't have to, but they won't mind -"

"I'm curious, actually, and I assume they won't stop being magical slaves if I don't look at them."

"I wish." Door open - "Hey, Nippy?" he says to the empty air.

Nippy materializes. "Mr. Timothy is wanting Nippy?"

"I need a really big favor, actually. We need my father right away to consult on something about Hogwarts security. Is there any way you can go to my house and get him, or call one of our family elves?"

Nippy furrows his brow. "Nippy can go and tell the family elves if it is for Hogwarts security, Mr. Timothy." Fervent nodding. "What is their names?"

"Niblet, Whimsy, Tipsy, Whoopsie and Daisy. Thank you very much."