I'm from another planet, and didn't get here by magic.

"...Which brings me to, what can you do besides grant wishes - be telepathic, be invisible to some people, anything else?"

Not very much within my energy budget. I certainly can't take you to another planet unless that is your wish. I can tell who could be a puella magi, and I can safely collect witch byproducts so that they don't hatch into more witches here.

"What's the limit on how much mind magic a puella magi who used her wish in an optimal way could do or get?"

It depends a lot on how her wish is shaped. Outright mind control is possible, but only when your soul is still in your body, so once you're a magical girl you'll be safe from that. And it's not something most magical girls could do at all, or at least not efficiently, if they wished for something else.

Bella shivers. "How long do I have until I'm too old to make a wish? And if the answer is different, how long until you give up on me coming up with something and go talk to someone else?"

You'll be too old when you turn eighteen. You might have a decline in available wish power before that, but not very quickly. It seems like you really want to make a wish, so I'll be nearby until you make it or you can't unless that changes.

You're welcome.

There's a couple more questions on the list. "Which laws of physics can be ignored by magic? And why is it only teenage girls?"

Most magic doesn't exactly ignore the laws of physics. It changes the things that physics are acting on. If you use telekinesis to pick up a rock, as soon as you stop using magic the rock will fall normally. It won't be very light forever, or float in place. If you transmute something into something else, then the laws of physics will work, they'll just work for whatever the new material is. Other things, like witches' barriers that they hide themselves in, or invisibility, ignore things like space contiguity and how light is supposed to behave, but usually wishes and puella magi magic use can go on without strictly ignoring any physics. Girls in their second stage of development have more usable emotions to brighten their soul gems. It's pretty confusing to me too, but that's how it always seems to work.

"Is it possible for someone else to eavesdrop when you talk to us telepathically?"

I'm the relay and I won't send thoughts to anyone else you didn't mean to send them to.

"And nobody can wish for eavesdropping powers? Or they haven't, at least?"

I can't tell you what anyone else has wished for, it reminds them.

"Well, then, we can't be very sure nobody's eavesdropping on your telepathy, can we."

Tailflick.

"Well, it sounds like it would at least take general mind-reading, doesn't it? And you're pretty sure Ghys doesn't have that."

"If I had a wish in mind already that was at all reasonable to tack 'and also hear everything Kyubey ever says to anyone' onto, I could see trying to get it as a rider," says Solvei. "I'm pretty sure Ghyslaine doesn't have that because, as we've implied before, she would've killed us already. And I'm likewise pretty sure she doesn't have general mind-reading. But someone else could, and that would be much less dangerous for us but still wouldn't be ideal."

"Yeah, if we run into other puella magi. But are we likely to do that before being magical girls? We're safe once we've made wishes - I guess Kyubey might not be."

"Yes, that's the question. Is Kyubey a secure message relay, or not?"

"And I guess what we have is 'yes generally, maybe not if somebody with a specific interest in espionage is nearby'. ...How many magical girls are there in the world?"

Almost three thousand.

"That sounds like a weirdly small number given how many people there are in the world. I guess I don't know how many of those are teenage girls exactly - but it's got to be a bunch - or how many have magical potential, or how much attrition there is from killing each other over resources... it does kinda suggest there isn't a thriving community of immortal magical allies going strong somewhere, or at least not a very big one."

Mostly magical girls compete with each other or stay in their own territories. Sometimes there are small teams, covering a larger area.