"Earth spent a while with two of the most powerful nations both openly having systems set up so that if one fired on the other, the other would fire back and wipe them out even if the first strike killed them all. It was called 'mutually assured destruction'."

"That sounds like the sort of idea my father would come up with. But not act on. Because he'd find the incentives elegant and then remember he's not actually a mass murderer. I suppose now he technically is. But he still wouldn't do that."

"Good. They backed off it eventually but it was hard."

"And with no backups, too."

"Humans in general believe they are operating without a net. Limbo's not common knowledge, nor that some daeva are ex-humans."

"I wonder if there are differences in temperament or just circumstances."

"I'm gonna guess some of both."

"You said you were murdered."

"Yep. I was teaching a class and he walked right in with a gun and nipped me in the head."

"...

Is that common."

"No - well, it's commoner than 'completely unheard of', but no. He was really mad at me."

A bitter smile.

"Why's that?"

"Oh, he was relying on the extreme obscurity of daeva to maintain certain kinds of economic scarcity he wanted to profit off of and it turns out I wasn't quite anonymous enough when I blew the secret open."

"Your world had material scarcity. And you ended it by teaching people to summon daeva."

"It still has a little material scarcity. Demons having our terrible reputation and all."

"You should really lead with that, I'd have trusted you with everything critical immediately."

"I'm in the habit of not telling people. Murderer didn't, I only know why he shot me because he cryptically informed the police that I had ruined his livelihood."

"It's more revealing of your priorities and reasoning than general declared friendliness, much as I appreciate general declared friendliness. It must have saved millions of lives."

"I did an estimate once! It is very rough but the estimate is in fact billions at this point!"

"Congratulations! And now you get the chance to do it again, if we are smart enough to think our way out of this bloody catastrophe."

"That's the dream."

"And either way you can go home and teach your people light-leaping. Or will they be idiots and not let you talk so you can't even explain light-leaping is on the table."

"They will be idiots, but some demons sometimes get to talk so I just have to publicize it in Hell."

"I am imagining some summoner a few years from now is unconcerned with being talked out of their soul and summons someone, only for the demon to start dancing in joy and saying 'we can finally tell you! we figured out light-leaping!'"

"Entirely plausible! Or, more likely, our correspondents in Fairyland get to tell somebody 'hey, summon a demon and get them to make you a light-leaper'."