"Objections from people other than you."

Cam has no objections. He offers McGonagall a pair of shades.

"Thank you." She transfigures the shades to match her prescription and swaps out her spectacles.

McGonagall in mirror shades looks extremely weird, but nobody is going to point this out. They set off, McGonagall contriving to both take the lead and not let Lockhart out of her sight.

Cam brings up the rear and conjures around corners.

There's nothing around the corners except, on two occasions, cats.

"I don't understand your abilities," remarks McGonagall. "You're not an ordinary wizard, or a muggle, or any sort of magical creature known to wizardkind. Where did you come from, what can you do, what are your limitations?"

"My species is in English called demons. From Hell. I can make arbitrary nonmagical material objects."

"And this 'hell' contains what, exactly?" she asks suspiciously.

"It started out containing literally nothing and now it has whatever we put there. It's a perfectly nice place, if a little too often radioactive for humans to be comfortable."

"And you have no designs on human souls?" she asks, with the gaze of a woman who can hear ten students say their cat ate their homework and pick out the two whose cats really did.

"None at all."

"Good." The "you better not" remains unspoken. "And exactly how arbitrary is arbitrary objects, besides not being able to make enchanted items?"

"No antimatter, nothing including vacuum unless I start it in a vacuum, nothing that begins in motion but there's ways around that, I have a volume per time rate limit and a range limit but they're big, I have to know what I'm making to pretty high granularity if I'm inventing it or be able to identify it by conjurable parameters if I'm copying it, I can do format conversion but not translation, and if I make animals they come out real dumb."

"Those are fascinatingly different from the limits on conjuration as we know it. Except for the part about animals; conjured or transfigured animals are in most cases extremely dim."

"An interesting commonality, that. Couldn't tell you if it means anything."

"Neither could I. There are theories as to the cause, on our end, but nothing definitive. More immediately, how did you come to Hogwarts?"

"Demons can be summoned. I didn't know there was something unusual about this summon till after I got here."

"I didn't know muggles knew how to summon demons. They do keep coming up with new things, don't they."

"This isn't the universe I'm usually summoned to."

She looks at the trio. "How do you three manage these things?"

Shrug.

Shrug!

"The book said it was a scrying spell!"

"It's very irresponsible of the author, may warrant looking into once the immediate mess is handled."

"Yes. The author may or may not have known what they were doing. I haven't heard of any spells summoning people from other realities before."

"Maybe it's some kind of fluke but it bears looking into."