"No idea how subtle arts will interact with this."

"Let me finish dangerous things and then we'll get to magic systems." Dangerous things! There are a lot of dangerous things! Iris sometimes interjects. 

What a fuck of a lot of dangerous things. "I'm sorry if I scared people by looking like a dangerous thing."

Shrug. "I prefer dangerous things that look it to dangerous things that don't, honestly."

"That is reasonable but I still don't like frightening people."

"If it seems strategic we can vouch for your friendliness. Magic?"

"Do tell."

"Three kinds. Subtle arts technically isn't magic - doesn't show up in magic detection - but I take it it's unique to here. You're born with the aptitude or you aren't, and some species don't have anyone with the aptitude. It permits reading minds or shielding minds against reading, altering memories or affect or associations, it's possible to use it to condition people to do or not to do things, or to make it impossible to form an intention. The latter of those take a long time and subtle artists doing it without consent get identified and shut down fairly quickly. They also sometimes have telekinesis. 

Arcane magic is the basis of wizardry and several other disciplines; you cast spells from scrolls until you learn them and then can cast them at will, though you only have so much mana - it increases with practice, and regenerates when you're resting - and until you've been practicing for a long time you don't have the mana for powerful spells. It's safe to cast spells you learn from someone, it's not safe to experiment with gestures or spell components and see if you can get more powerful. Anyone can learn a very simple spell in a couple of hours but if you're new to it you won't have much mana. You can also work arcane magic through music; I do that.

Divine magic is granted by a god, usually - there are secular druids but not an explanation for how they get their powers without one - and there's some overlap with arcane but it does things like healing and resurrection, the former of which is hard with arcane magic and the latter not possible as far as we know."

"I should not 'just pick up some wizardry while I'm here'," Cam says. "...it's funny you do magic music, Ardas - Flat Ardas, those being the ones that aren't Space Arda - have magic music and Elves sing a lot."

"Learning a cantrip is generally a safe thing to do, but I respect erring on the side of safety."

"I mean, if there's a cantrip that would be intrinsically useful to know for me, I might be able to stop there, but I definitely shouldn't learn some as a curiosity or on general pick-up-stray-magic-one-finds-lying-around principle."

Or so he can go teach everyone in other worlds. "If you find yourself inconvenienced you can mention it and I will let you know if there's a cantrip for that inconvenience."

"Hey, Cam, is 'bunch of people in the Imperium have disappeared' the sort of thing your evil god might pull?"

"Yes. Have a bunch of people in the Imperium disappeared."

"This is, like, not the most reliable source in the world, but let's say rumor has it that a bunch of people in the Imperium have disappeared."

"Any details on how they went?"

"Consensually, it looks like: someone offered to summon them to a nicer place, some people went through and confirmed the niceness of the place, more people went through. Some of them left letters telling their friends not to worry..."

"That's not really his standard modus operandi but it's not beyond, like, Sauron..."

"And if it's Sauron, they are probably not in a nice place one writes home about to convince their friends to come?"

"Oh, they might be, for now. A Sauron was the democratically elected ruler of a country, I don't think he even rigged it - the humans and werewolves in Elentári liked him fine till Loki stepped in and told them what was going on - but if it's Sauron they are not in circumstances conducive to longer-term flourishing."

"That's not enough to take to the emperor of the Imperium."

"No, but we could get travel papers and go investigate - it doesn't sound like the site they're disappearing from is dangerous -"

"Might be worth doing."

"I'll run it by my father. It's a week's travel from here unless it's urgent on that time scale, in which case we can spend half the budget on rings of teleport and have the Imperium annoyed with us for popping in."

"How long have people been disappearing for?"