She makes a token effort not to laugh; it predictably fails. "I mean, it would be sort of unfair. But I suppose this is the sort of evil plan I don't feel obliged to thwart at all costs." Her face goes somewhat more serious. "But it's not like there aren't daeva who really are planning terrible things."

"I guess we have more practice time but you could institute an age limit! It's not like human athletes can't get angel buffs no testing can reasonably catch... Anyway, yes, some demons are mean people who think it's fun to take a scared desperate human and offer them what they need in exchange for their soul."

"I see. What does losing your soul do, anyway? Not really a thing I was planning to empirically test."

"The reported effects vary widely. As you may imagine I have limited opportunities to talk to humans, you are actually the only summoner I've ever had who's let me talk."

" - gosh, ever?"

"Ever! I have terrible luck. Once I got summoned by a linguistics department studying demon languages and they didn't let me talk! They just had me point to the correct translations of things so they could verify that the demon they were allowing to talk wasn't fucking with them."

"Wow, that does sound frustrating. My condolences."

"Thank you."

Aww.

"Uh, so anyway, I probably don't know enough to keep asking useful questions for an entire hour, let alone two. If you had your heart set on giving your lecture you can totally do that."

"I don't know that I'd go as far as 'heart set' but I would be happy to. Is here good? At some point I'm going to want wall space to safely display circle examples."

"Oh, yeah, here works." She motions to an empty wall.

Cam doesn't put a circle up on the wall immediately; instead he makes a little computer peripheral that projects onto the wall and starts a slide show going. "What do you already know about daeva, first of all," he says, before moving beyond the title card.

Oh boy, probably nothing. "Uh, there are three kinds. Angels change matter into different matter, fairies move things around up to the speed of light, and demons make new stuff out of whole cloth. They all live in their own dimensions, but can be pulled to this one by a summoner. They're indestructible and therefore can't be killed, so if someone botches a summon and a hostile daeva goes rogue, you have to either get the summoner to dismiss them, or else kill the summoner if dismissal is for some reason impossible. You can't dismiss a daeva if they've done a task that you haven't paid for. All of them are really dangerous, which is why it's important to bind them properly, so there are limits on the sorts of things they can do. Uhh, people have probably been summoning them for a long time but it was only turned into a proper field of study around a century and a half ago. Um. Oh, they can't have children, which is why angels and fairies are willing to do lots of stuff for the chance to adopt human children. Martian power grid runs on adoptees. Possibly demons would too, if the masses were aware that there existed non-evil demons or if non-evil demons were more willing to take summonses. There appears to be dispute about the evilness quotient of demons in general, though the consensus position is that probably they are super evil." 

"Fairies only approach, not match, the speed of light," Cam corrects. "Otherwise that is all correct."

She notes this down in a notebook. "OK! I know slightly more than nothing." 

"It's a decent foundation! Okay, so this is the bare minimum of circle -" He advances the slide. "As you can see it is a circle reading 'I summon a fairy', you can't summon a daeva without specifying species but I'm sure you can complete the analogy to the other minimum circles. This will get you a totally unbound, loose fairy, whichever one picks up the summon. Random summonses are not distinct from each other in any way, except by timing - to the limited gradation of 'just a few seconds ago' versus 'longer than that'. Oh, and I guess if one is wearing legible clothing that will filter out circles with gags."

Notes notes notes. "So do random summonses just, like, go out to everyone of the relevant species, and it's first-come-first-served? Are you just constantly getting little notifications about all of the summonses anyone is doing anywhere?"

"Yes, but they're easy to ignore if you don't want to pay attention to them. Specific summonses are harder to ignore, but still not that bad -" He advances to the next slide; this circle says I summon the fairy Titania. "Titania is a real fairy who refuses to change her name or show up on demand! She has a bunch of circles like this but with some binding, out all the time, and she just ignores them. But -" Slide. Photo of the Ganymede circle array: hundreds and hundreds of them. "If there's enough of them, it's very hard not to take one. Still technically a voluntary action, but it's like scratching an itch, say. That's how the Ganymede Circling Police makes arrests when they want to catch a daeva and jail them."

"Gosh." Doesn't really have any follow-up questions to that slide, although she is now vaguely wondering exactly how long Titania has existed.

Slide. Circle with a binding. "This kind of circle was in vogue before summoning was a seriously studied field. The binding isn't very safe, but it'll do against an uncreative daeva - especially one who doesn't know very much science because it's 1462 and you can't play tricks with chemistry you don't understand - we have separate science from you guys, but they're not uncorrelated. Fairies are less affected by the march of progress, angels and demons much moreso. Here's this binding in non-circular form for easy reading..." Slide.

Notes notes notes. "I imagine secretly evil Cam has close to zero trouble circumventing this one, though."

"Secretly evil Cam with real Cam's knowledge of physics, bindings, etcetera, can, given this circle and even a perfectly negotiated task..." He advances the slideshow. There are a lot of options. "The ones marked in red are the ones where the summoner can die, the ones marked in blue are the ones where secretly evil Cam can put them in a coma and run moderately amok. Not very amok, this binding isn't nothing, but a little amok."

Thoughtful nodding and more note-taking. 

"So some savvier summoners, close to Revelation-time, were working on ones more like this," slide, this one has a lot more words in the circle, "which hedges out a lot of those contingencies, and there are even things that make negotiation itself better - no letting daeva misrepresent their skills, for instance, so you don't wind up giving an advance payment for something they aren't competent to follow through on, that's an important one - and things have gotten more and more complex and sophisticated," slide, slide, "till you wind up with very legalistic Safe Summoning Authority preprints," slide, "which are properly the gold standard for typical amateur daeva employers summoning randoms, but you might want to homebrew your own binding if you are summoning a non-random daeva or have a specialist need. For instance, here is the circle used for the typical Martian power grid fairy..." He slides along. "You'll notice this binding is about a third as long as what you used to summon me. This is, approximately, because they let Martian power fairies adopt children - they're screened on a personal basis and they aren't assumed to be about to snap. This binding will prevent a startled or emotional fairy from doing something in the heat of the moment that wouldn't permanently injure anyone back in Fairyland. It'll prevent them from evading authorities if there's some reason they're under suspicion. It'll stop them breaking arcologies, since that would be enough of a disaster that you don't want to even theoretically allow it just to give your long-term resident more flexibility, and it'll stop them from coercing their summoner by any but the most hilariously indirect means. But if a Martian power grid fairy wants to knock down their neighbor's house, take a joyride to Jupiter and back, accelerate their child to sixty miles an hour either recreationally or because there's an emergency, dig a giant hole in the surface of Mars? This binding allows that, because you don't need to cripple a nice person that far."

Notes notes - she should ask whether she's gonna get to keep the slideshow afterwards, but she doesn't super want to interrupt right now, and also the note-taking is good for remembering things even if she never looks at the notes again. (Though she will. Probably several times.) "So what all does the binding you set up prevent you from doing? I double checked it all but I don't know that I actually understood it all."