"If we knew we would probably be closer to stopping it happening. Current best hypothesis is that some combination of the inherent nature of Hell and the negative emotions of its inhabitants coalesces into something aliveish and usually--not always, but usually--malignant."
"Well, why do things that aren't demons exist?"
"The universe has always existed, as far as we can tell; even God isn't older than it, but she's older than all the things in the universe. She...did some things I can't really explain very well until you know more physics than you currently do, to make there be stars and planets and stuff. But to make the angels, and the humans, she had to give up a lot of power over Earth. She can still do whatever she wants with Heaven, and it's a lot nicer there, but everyone who isn't an angel or a demon starts out on Earth. Or Fairyland, which is its own can of worms."
"Why did she have to give up power to make stuff? What's Fairyland like?"
"Angels and humans are people, which are way more complicated than anything else. It didn't take as much to make angels as humans, because when a new angel comes into existence God makes it directly. In order to create a chain of self-perpetuating soul production, God had to invest a lot of divinity into the species that eventually evolved into humans. Fairyland is a sort of alternate Earth, but not quite. It's...if Heaven and Hell are ninety degrees away from earth in opposite directions, Fairyland is ten degrees away in a third direction. Does that make any sense, or do I need to come up with a better way of explaining it?"
"Fairyland looks like Earth, but with different plants and animals, mostly, if that was what you were asking; I was trying to explain the metaphysical nature of it. And it has fairies, of course, which are like humans only different. They don't die of old age, they reproduce the same way as humans but slower, and they have some magic that humans don't."
"Does that mean fairies don't go to heaven, or that they have to wait to die some other way? Do humans have any magic? Can I learn magic while I'm waiting for my divine powers?"
"Humans don't have inherent magic but there is magic that anyone can learn to use. I know some of the theory but have never practiced it; there isn't much call in Heaven and I reiterate that I haven't spent as much time on Earth as I would like. I can teach you some but I think it would probably be best to find an actual practitioner to tutor you. Fairies can die, and if they do they can go to Heaven same as anyone else."
"I want to learn magic if I'm not going to get a lot of divine powers very fast. Especially if my divine powers are going to be silly like the wine thing."
"The magic's pretty finicky and takes a while to learn anything practical, but yeah, I hear ya. Oh, hey, speaking of, one of the other things besides teleporting that I can do occasionally but shouldn't do often is invisibility. I cannot believe it didn't occur to me to ask this until now, but do you want me to turn us both invisible for a bit so I can take you flying inconspicuously?"
So she scoops her up and turns them both invisible and goes outside and takes off.
And the little messiah she is carrying whoops with delight.
After a few hours, she regretfully murmurs, "I need to land soon so I don't overextend myself on the invisibility."
"Okay," says Mehitabel understandingly. "You can find me a magic teacher instead, that's okay."
"Yes. Although that will take a little while, and I do know some theory, so it'll be just me to start with." She lands, and as soon as they're inside she sheds the invisibility.
"Are there anything besides humans and fairies and demons and angels? Any people anything, I mean."
"There's lots of debatably-human stuff, like vampires and werewolves, that definitely used to be human whether or not you count them as currently human. And some things that are the descendants of humans who decided to magic themselves into another form and go commune with nature, like Yeti or swampdwellers. Actually fairies are the descendants of humans who did magic to themselves too, but they like to pretend they're not. I wouldn't advise doing that, though, even if you were just a bogstandard human; the survival rates are discouraging. If you were just an ordinary human and decided it particularly mattered to go on living on Earth instead of Heaven I'd recommend vampirism, personally; its bad reputation isn't totally undeserved but it doesn't actually do anything to your brain, it just gives a certain class of person an excuse to live down to the legend."
"If something does happen to me and I go to Heaven before I'm done doing everything can I come back?"
"I think it depends on what happens to you. Let's go with 'probably.'"
"What might stop me? Why don't people come back all the time, when people who are still alive miss them?"
"People don't come back all the time because God's powers on Earth are limited and it would be impossible to bring everyone back, and how would you choose who gets their loved ones back and who doesn't? I don't know of anything that would stop you, because you're a divine being--theoretically, sending you back to Earth shouldn't be any harder than transporting an angel to Earth whose physical form had been destroyed once. But I do know that messiahs are fundamentally different from angels on a number of levels--you are human as well as divine on a fundamental level; I can look it, but I'm not. It's theoretically possible that some demonic power or great spell that I don't know of could damage you to the point where it would take more power than God has going spare to send you back. I don't think there is, but I don't know, not for certain. ...Considering that it's never been done, and trust me they would have wanted to, I'm pretty sure you'd have to get tricked into it, if it were possible at all."
"I will try very hard not to be tricked," nods Mehitabel. "Is there math about how much power God has and I have and you have and how much it costs to do things? It seems like there should maybe be math of that."