"Hi! I'm Timothy. I don't know if word has gotten around yet that there are worlds other than the one you're normally summoned to?"

"There've been rumors going around..."

"The rumors are accurate! Well, actually I guess I can't speak to that. But there are in fact other worlds. I'm from one. It has these things called Dementors. They can't be killed, and they make everyone in close proximity depressed. If you spend enough time right near them you start experiencing the worst moments of your life, over and over again. My world made a deal with them; they can feed on our prisoners, in exchange for not bothering anyone else."

"...Ew," says the fairy.

"Ayup. Want to dump them in deep space for us? It's a much better solution."

"Sure, but I need at least a token payment to leave the circle."

"We've got a demon on board with the project - needed a more humane prison once the things are gone - and he'll make you whatever you want within reason."

"Oh, excellent. I accept."

"Cool! I didn't get your name -"

"Treeleess."

"Pleasure to work with you. Demon's inside, I'd prefer if you grab your payment up front so if anything goes wrong I can dismiss you - there's no reason to expect it will, you can stay very far outside their range the whole time, but just to be safe -"

"Some things I want are large and it may be inconvenient to keep them close enough to bring back with me while performing tasks."

"Okay. I really don't expect anything to go wrong, so if you'd rather collect afterwards that's fine." Back inside.

"Alternately you could resummon me later with a token task, and I could take partial payment now."

" - sure, let's agree on small stuff now and then if for some reason we are prevented from renegotiating to give you more stuff afterwards, I'll summon you back for it."

And she gives Cam a list and arranges her stuff on her person.

And he says to Cam - "I am not expecting wizards to arrive to interfere - no chance they'd arrive in time to interfere with dementor removal, only might have a chance to react before we have everyone relocated if rounding up the prisoners is more convoluted than expected - but if they did, I don't love having the fairies hold them off and invisibility seems likely to impede them significantly. Can I have a binding for Ister that lets me use him to nonlethally incapacitate people if needed -"

"Are we assuming wizards react to drugs like everybody else, or that he's wrecking wands, or...?"

"I'm willing to bet wizards react to drugs the same as, or by recovering more quickly than, Muggles, and I'd prefer that to wrecking wands because wrecking wands will make everyone hate me."

"He could also tie people up or something, drug dosage can be fiddly and he isn't medically trained so he won't know what to look for if he can't go with a simple algorithm because the wizard metabolism keeps throwing him off..."

"I'd expect the sort of people sent to investigate an Azkaban breakout to have defenses against being suddenly tied up, which is a thing our magic can do. Standard drug dose and then wreck wands if that fails to work?"

"Okay." And Cam draws up an alternative circle.

And he completes it.

It's Ister! He smiles at Timothy.

"Hey! Want to do the Imperius again? I need a moon colony, it'd probably be a couple hours."