"Well, I don't know if I could do it between worlds, but within one, distance isn't a factor. I just need a focus - something the target owned, or someone they met, or someplace they've been or ideally all of those. Why?"
"Your world doesn't have witches. No one will have any idea what's happening, will they?"
"Yeah. I'll take a deserving target. Really deserving, I mean, but in a world with no witches there probably are some - I mean, in my world, anyone who's publicly awful doesn't last long without an allied clan casting protections, but in yours..."
"Excellent," crows Bell. "And Sherlock, Tony, you guys have met Snow and probably any number of other unpleasant people we'd like to die of - what will it look like, Isabella Amariah?"
"A long-distance death curse? Easiest is probably to just amp up the non-death one that causes the flulike symptoms until they die of dehydration, or maybe suffocate from congestion, or cook themselves in fever," shrugs Isabella. "I can layer it as much as you want so it takes a satisfactory amount of time regardless of whatever medical care is involved. You do have to convince me that the person is bad news, though."
"We can provide something he has owned, somewhere he has been, and someone he has met," says Sherlock. "As for how bad he is, would you like the personal reasons or the political ones? He is both an old family friend guilty of a litany of betrayals and the president of our viciously unpleasant totalitarian government."
"If I'm going to kill this guy I need the whole story. If you just want him to be hospitalized for a couple of months either will do."
"Bell, perhaps this would be a good moment for your summary of the Hunger Games."
"And you want me to kill your... king? dictator? the guy who invented this sadistic excuse for entertainment except it's apparently been going on long enough that a human would already be dead?" asks Isabella.
"President," Sherlock reiterates. "He did not invent it, no, but he does take a significant personal interest."
"And when you win, he puts you up for auction to all his rich friends and threatens to kill your family if you don't fuck the winner," says Tony.
Isabella looks like she's considering asking Tony a question, possibly how do you know that, but instead she says, "If the Hunger Games part is all on TV I assume you'll be able to produce more evidence than your word, and if it corroborates, I will be happy to present you with a dead president deceased of a mysteriously infection-free flu. Over any time period you like. I'm not philosophically opposed to well-targeted revenge."
"All right then. And I hear that one of you can open a door to this place to send me home with reasonable reliability?" she asks. "I can wait around a bit for you to see about magic contagion, if it'll really be the same time when I go home again."
"It's not perfect about that, but it's close," Bell assures her. "So, have you taken over your world yet?"
"How did you know I'm going to do that? I haven't yet. I need something that I have not yet found, but I was in the middle of a spell to locate it when Kas found the door."
"Well, I don't think I'd be doing it any time soon if it weren't for the existence of alethiometers," says Isabella. "It'd certainly take me a few decades, maybe even centuries - witches have specialized in magic before and not wound up accumulating the kind of power I'd want before I'd be comfortable making an open bid for world domination, you know?"
"You're the first one of our template I've met," says Bell, "but I've been recognized in here before, and we frequently take over the world."