Well, and boys have emotions and yet are never puella magi, I don't really know what makes emotions fuel-grade.

If adult Elves can do it then I can recommend lots of people. It's probably even worth all the complications.

Well, we can check when we're ready if you can make a wish, but you're only half-Elf, so I don't know if we should expect you to work like the others.

Probably not. Our world also has Men, they might be more like humans.

What do you know about them?

Um, they die? Even if nothing happens to them, they just get old and die. And they have free will, they can't do oaths. They can have children by accident. They're shorter than us.

...sounds pretty humanlike so far, but if that's all you know hard to be sure.

Yeah, I haven't met any. Lots of them worship the Enemy.

I'd like to say worshiping obviously evil entities doesn't sound humanlike...

He might refrain from attacking communities that worship him or something, I'm not sure. Lots of them are vassals of the Noldor and fight the Enemy, too.

Definitely can't rule out that they're my species. Importing fluffs is still a risk, but I think if they get what they want they'll basically be amoral economic agents. They harvest emotions the way they do because it's efficient, not because they enjoy causing suffering or anything, they don't enjoy stuff.

So if we can give them a better way to harvest emotions - 

- though the Enemy might make them a better offer.

They want to stop entropy. They're close to escape velocity on that, or they wouldn't let a witch get big enough to eat the whole world. I don't know if they have a next goal after that but it is definitely a risk.

I don't know if awful suffering is an emotion or if the Enemy'd be willing to switch to making his prisoners alternately ecstatic and miserable but he would probably make them the offer.

I think it's 'despair' more than 'suffering' per se, they're drawing something out of the contrast between 'yay I just got a wish' and 'everything is horrible forever'.

Bet the Enemy could sell them despair. 

I'm reasonably confident the wish part is functional. It's a lot of investment of energy - the exact thing they're trying to harvest - and they have to pay it up front even though a girl who dies in the line of duty will never witch. I doubt very much they involve wishes because they care about consent per se except as part of the emotional state they're looking for.

Okay. Well, that's something. I think it's still better than leaving the fate of my world up to its own chances, they aren't looking very good.

If nothing else the fluffs only prey on a small fraction of the population and leave everybody else alone except insofar as everybody else is potential witch food.

And Mother might be able to keep them out of Doriath and nowhere else has Elven children.

What's the significance of Elven children in particular?

If it's restricted to adolescents, no Elves will be offered it.

...and?

I bet Dwarves can't, the immunity to mind-affecting magic. So it'd be Men.

This is entirely plausible but I can't figure out why you think it matters.