"Anyone with hundreds of years of experience taking summons is probably better at loopholes than I am at avoiding them. I might just stick with unedited, known safe summons from those books until I'm sure the daeva in question isn't a malevolent being of pure evil."
"That is a solid approach. I can also draw most of a circle for you without the possibility of incorrect transcription as long as you make the last mark."
"That sounds even safer, but limits summoning to whenever you're here. Would it work if you make a stack of papers with circles, or make a floor with most of a circle carved in it?"
"Papers work, carving won't more than once unless you pour water into it or something each time - and I can't make the paper secure against attempts by other people to use them. Nor for that matter a carving."
Well, this castle is riddled with secret compartments and passages; nobody'll notice one more hidden bookshelf."
"I suppose you could put a carving under a rug, but it will have to stay unrugged the entire time you have a changer in it for negotiations or pending dismissal."
Better to stick with the books and a few pre-made papers. Those I can hide indefinitely."
"Sure. I can do them mostly in invisible ink, it occurs to me - as long as you have the same thing in your pen you can finish them if I indicate where to draw in some visible material."
Let's go for it.
Anything else I need to know before summoning one? What kind of payment do changers usually ask for?"
"I can pay changers pretty easily. When I'm not around, of things you can procure here, they may also be willing to take pets - I assume there are dogs and cats around - and potted plants and reading material and interesting art objects."
He leads the way down to the nearest cellar. "This isn't the most comfortable part of the castle, but we don't need to worry about being seen or heard down here."
"No reason not to, as long as nothing looks too out of place. And there's leeway on that front; nobody wonders why someone hung a tapestry in a cellar and arrives at the conclusion that it was magic."
"Maybe I'd better be here for a little longer before I start trying to make decorating decisions based on what will or will not look out of place, though."
Anyway, shall we try for a changer?"
And lo, there is a sheet of paper, almost unmarked except for a rectangle of four dots in black near an edge. Cam hands him a pen. "The gap I left in the line is inscribed in the space of those dots."
"Er, hello." he says to the winged person in the circle.
"Remember, don't agree to anything I haven't vetted, the task is also a possible point of failure," Cam tells Hank. "Possibly nothing," he adds to the changer, "this is his first summon, although we may want to note your name for future use."
"Eyndiel," she says.
The hard part is secrecy; daeva aren't common knowledge and should stay that way. Can you turn yourself into a bird or something for the occasion?"
"Yep," says Cam.
"You have a demon who objects to making houseplants?" she asks, raising an eyebrow.
"Nope, your summoner here described it a little over-constrained. Houseplants are doable. If you want a demon kitten there's no obvious reason you can't have a demon kitten, usual caveats about demon kittens apply."
"Anyway, I don't want to be a bird, but I could take off my wings and tone down the colors for the occasion," says Eyndiel.
"The color-coded locations I mentioned are spread across the country. You'd probably be conspicuous for covering that much distance, if nothing else. Come to think of it, how long would it take you to turn things to air? And do you need to be close?"
"It's his first summon, be nice," says Cam. "Her range can be summarized loosely as line of sight within about fifty yards, close for detail work, farther for a few simple things. She's also slower than a demon for comparable amounts of matter influenced, but if we did give her a scooter she could clear trees and stuff in front of her at a sedate scootering pace as she traveled."
Hm, anyone who sees a scooter would just assume it's the next thing to come out of Camelot. It's not so far beyond a train as to be implausible.
What kind of pace counts as sedate?
Oh, and Eyndiel, you're in the year 536."
"Er," says Eyndiel, "come again?"
Are you up for cross-country transformation? It could take, let's say ten hours to complete a line, or whatever fraction of that you're willing to do. A houseplant seems like kind of inadequate payment for that."