"Is that the nearest entrance to the rest of the city? And can't you teleport me back there like you did earlier?"

"It is, yes.

I can teleport you back, but you'll most likely need the directions for the return trip. Where should I drop you off?"

"Directions for the return trip?"

"For whenever you come by here next. Since I wouldn't necessarily know when or where to teleport you from."

"Ah, quite. I would also, er, prefer not to be eaten by whatever it was that was trying to eat me."

"They won't be back again, probably ever. If anyone else attacks you, tell them you're a human not a vestige and they'll know it's against the local rules. If that doesn't stop them, you have all the high ground and can threaten them with being forsworn. It'll stop them."

"Ooh, that's a good one, then. In that case I suppose I should just walk back? To get to know my way around?"

"You can walk if you'd rather, but it is a theme park where the theme is hunting humans for sport. It can be a bit unsettling. As for knowing the way around, it's Jacob's Bell except that all roads lead here."

"Oh. I'm confused, if all roads need here why would I need directions for the return trip?"

"For getting in to my domain in the first place. Once I'm not secret it'd be possible to just walk north until you're here, but for now the entrances are still hidden."

"Ah. Well, I know Jacob's Bell well enough to find the place I came from. And by the way, you said I was to use something of power on the brick wall—what other kinds of power sources are there, than blood?"

"The specific forms are too many to list. Others have disparate types of natural abilities, some practitioners store their strength or speed for future use, maybe there's a magic jewel infused with light from a unique source. Not all things that contain power are equally easy to harness.

The most important power sources among practitioners are the demesne, implement, and familiar."

"Right. So I see." She stretches. "I think I have a whole lot of reading and preparing to do, then."

"You did get all this dropped on you at once.

Should I teleport you anywhere in particular, or just out to the exit?"

"I did! Hopefully next time I catch you there'll be less in the way of life threats and more in the way of actual meaningful interaction. It's not always you meet a cute altruistic ambitious boy, I should make the best of this. Yes, unless you can teleport me to an unobserved location around home, just out to the exit's fine."

No comment on those adjectives. "Come back any time. Especially when there's less mortal peril involved; that's always better."

The penthouse appears to dematerialize, and Sadde is back on the Euclidean side of the entrance.

She walks home, with a spring in her step. She looks around attentively as she does—are there any people that she will now suddenly realise are not actually humans?

There are at first. A handful of what look like extremely ugly children at first glance and small humanoids at second. The largest of these ones is half her height, but several of them carry wickedly serrated rusty tools. They scatter and disappear from sight when they notice her looking.

How the heck did she never notice them? Serrated rusty tools? Seriously, her brain managed to hide that from her?

The objects looked as much like toys as the Others did like children. And it's entirely possible that this time yesterday she wouldn't have noticed them at all.

As she gets further south and deeper into the city, those don't reappear.

Naturally. She gets home, there's cold dinner in the kitchen, no one interacts with her, which is pretty good, so she eats some, brushes her teeth, takes a shower, and retreats to her room (i.e. the attic) to start reading Essentials.

It rarely goes into usable depth, but it's very broad. How the lying thing came about and why you must never do it. The precise traditions that affected the awakening ritual, so the new practitioner knows exactly what they're getting into. Some common types of Others and practitioners. (In both cases the classifications are humanly invented descriptions, not hard rules about how the magic works. It warns against relying too heavily the labels.) Instructions for the familiar, implement, and demesne rituals, along with what factors should be considered in the choices and a small handful of examples.

The book contains few things that she could theoretically do right now. It's more classifications and warnings than instructions.

Naturally. How about the demesne ritual, then, what does it say?

It's simpler than the implement or familiar rituals, and much simpler than the awakening one. Not a single magic circle involved.

Technically all that's required is speaking the claim, and then the local spirits take care of transmitting it to interested parties and enforcing stakes.

The actual text is equally simple. Most of it varies by practitioner; only a few lines are standardized. She could say it now, if she wanted to. I hereby make a claim. Let this be my statement. I claim this space and only this space. Let this be my challenge. 

By word count, the non-standardized part is most of the ritual. The practitioner states what their demesne is going to be: what it means to them, what they're doing and why they're doing it, what kinds of spirits they want to attract. Usually also a line about how it is to stay a place of sanctuary for their descendants after they die. And of course it ends in Let this be my challenge. If any would deny me this demesne, declare your right to challenge me and find me here. 

A demesne is supposed to be about claiming a place in the community as much as a place in the geography. It declares intent to stay, after all. The spirits react accordingly and concentrate on telling prominent practitioners and Others that there has been a claim. Those listeners get shown the voice of the claimant and where they are, and once they arrive they get first say in declaring a facet of the challenge or excluding something. The book suggests that getting on good terms with likely challengers is at least as important as preparation for defending against them, even if it's less exciting.

Once you've finished the challenges, either by winning or by paying the agreed-upon forfeits, My last challenge met, I claim this place. And then it's your demesne.

Hmm. Does it say why people usually do it room-sized, or how? Where are the physical boundaries of the demesne declared?