"Demons have a reputation for talking people into trading their souls for whatever task, the gag is a binding developed to prevent that. With it, the daeva can only communicate in pre-specified phrases, typically 'yes, summoner' and 'no, summoner'."

"...are they really persuasive...?"

"I think it's more a case of desperate people willing to make any sort of deal and demons finding the prospect that they actually could claim a soul amusing."

"Oh, they can't do it? Some demons here can. And turning into a vampire evicts one's soul, that's why they're such sociopaths."

"I see. Souls have never satisfactorily been proven to exist in my world."

"They're not particularly obtrusive except by their absence."

"Are all sociopaths soulless? Can people who are born with the condition become vampires?"

"Enh, vampirism isn't exactly the same thing as sociopathy, it's just a shorthand? I think human sociopaths still have souls and can become vampires. My sources on this are handwritten old books by people who can't spell and actual vampires, so, grain of salt, but that's my impression."

"The vampire I met wasn't terribly inclined towards talking."

"They often aren't. Every now and then I get a chatty one."

"Have you ever asked what makes Sunnydale such an attractive place for them?"

"Answers range from 'it's the nightlife' to 'I dunno, I was following that guy you just staked' to 'heard it was a good place to start an apocalypse'."

"Why would anyone want to start an apocalypse?"

"Beats me, but surprisingly popular pastime."

"Is everyone who tries just incompetent or what, how is this world still around..."

"I don't really know. I mean, there's me, but there's only one of me and nothing actually stopping people from trying to start apocalypses in Tibet and nothing that would let me know about them in advance, and my power set is really stupid even when they're courteously local."

"You have a power set?"

"I don't just go around staking vampires on a baseline capacity. You know how much force it takes to get wood through a sternum?"

"Not viscerally. It is not really something that has come up in my life before."

"It's a lot of force. I can do that. But it turns out that super strength does not substitute for detective work, magic power, etcetera, so I'm trying to pick up a lot of slack here."

"Did you just wake up one day and realize you were really good at killing vampires?"

"No, I woke up one day and realized I could descend stairs without fearing for my life, and then later a god sort of thing appeared in my bedroom in the middle of the night and told me I had a mystic destiny, had I not been getting my prophetic dreams, I was supposed to get prophetic dreams? but no, I had not. Glitchy prophetic dreams. I also can't identify vampires with a spooky sixth sense. Everything else I'm supposed to have is in working order, though, it's not like the mystic destiny is under other circumstances well-crafted."

"I'm not sure what sort of explanation I was expecting but it was not that."

"It's kinda dumb!"

"Did the god-thing say anything specific about the mystic destiny, or are you just vaguely destined to be mystic?"