"Uh, okay, that has some pretty awful implications and forms a terrible incentive structure."

"Oh, wow."

"That's not even the worst part. Sometimes magical girls actively let witches grow and feed on people so their grief seeds can store enough despair. And there's a thing called a 'familiar' which is a shoot-off from a witch, it's less dangerous but still kills people except it doesn't drop a grief seed when it dies so some magical girls just leave them be."

"Grief seed? That the magic you need to survive?"

"Yeah, little evil-looking crystal things I can transfer despair to."

She shivers. "That is really horrible."

"Yup. Pretty terrible deal, I should probably have spent a good while longer questioning the Kyubey."

"The who now?"

"Little furry magical thing that grants wishes and turns girls into magical girls in exchange."

"Wishes?"

"Well, one wish per magical girl, but yeah, you ask for one and then become magical."

"How big a wish could you ask for, though?"

"That depends on this magical fuzzy 'potential' magical girls have. Most girls don't run into their limits, but the more potential, the bigger the wish they can ask for."

"Oh. What kind of wish could a girl with average potential get?"

"I don't know how much potential is average potential, and I didn't really ask."

"What was your wish?"

"...that's kind of a personal question, I think."

"Oh. Um. I'm sorry, I sometimes ask very prying questions, I'm so sorry about that," she says, and makes herself very small.

"It's alright."

"Anyway, I think I really dislike your kind of magic and I'm wondering if I can make you immortal in a not-lich way with venom."

"I'm not entirely sure how they'd interact. Any ideas on how to test it?"

"None that don't involve having to go to her world, which I'm thinking I might do anyway."

"But weren't you going to go to mine? How are we planning to do these, now?"

"Yes, that is a problem. Your world sounds like it needs immortal superpowered vampires less than hers, but."