"There's inexpensive magic that can ensure one's child inherits the potential."

"Some magic is 'expensive'?"

"More powerful magic generally takes more time and/or resources to perform, almost always takes more mana, and of course, the more powerful it is the fewer people can do it. Plus, of course, some things are secret. Something any witch can choose to learn and then do in ten minutes is going to be a lot more freely available than something only about a hundred people on the planet have both the power and the knowhow to pull off."

"How may witches are there?"

"Total? I'm not sure. Billions. On Earth? Hmmm...a couple million, maybe? Depends on how you define 'Earth,' really." 

"- space aliens, or, uh, magical witch colonies, or - what -"

"Magical witch colonies and alternate dimensions! --Mostly alternate dimensions. There's an absolutely lovely little city on the moon, though."

"And no one has noticed these millions of Earthly witches because..."

"Magic. When I said you wouldn't be able to see my shop if you didn't have witch potential, I meant it; there are lots of things like that. If I were a dryad and I walked out that door nobody outside would notice that my skin was green."

"If I'd been with somebody and I entered the shop what would happen?"

"Oh, you could have done that just fine. The Masquerade isn't that difficult to pull aside for individuals when somebody on the right side of it tries, and my shop is deliberately a little less hidden than most such things so as to ensure that even fairly weak potentials can find it."

"Did the shop - make me find it unusually noticeable."

"Yep!"

"Is there any more stuff like that involved in the awakening process or unavoidably in doing witch stuff after."

"Like it in what way, exactly."

"Doing stuff to my brain. Or I suppose other people's brains."

"Well...yes, of course. Everything does things to people's brains. I do recommend that you get into Psychotics if having things done to your brain bothers you, it's the elemental magic of the mind and learning any kind of elementalism strengthens your resistance to the element in question."

"Why is it called 'psychotics'?"

"Someone at some point decided that every kind of elementalism needed a unique name, as opposed to just something-bending or something-magic or what have you, and Psychotics is what happened to stick. I thought they should have gone with Psionics, myself, but you never can be sure what will happen."

"...'kay. How many branches are there?"

"Of elementalism? That anyone can learn, there's Firecalling, Windkeeping, Waterworking, Earthmoving, Naturalism--plant magic--Metallurgy, and Psychotics. There are also a handful of others that require special conditions to learn, like Lifeweaving and Arachnescence. Unless you're a sorceress, you can only learn one kind of elementalism you don't have an affinity for, although each kind will also accept a combination of two other affinities. Affinities are a race thing, the neutral--human, that is--affinities are body and soul."

"What... does soul magic do."

"Well, there isn't an elemental magic specifically for souls, that I know of, but having a soul affinity will make it easier to learn, say, runes, or necromancy, or divination. Among other things."

"...is there like a chart or something I should be looking at?"

"Hmmm. Let me see..." she disappears behind a stack of something, and the sound of ruffling papers emerges. 

Another woman with an equally absurd bust, wearing a maid outfit and a cowbell, emerges from a different direction, and silently offers May a plate of scones.